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16 pages, 3882 KiB

Open AccessArticle

Mechanical and Thermal Properties of Polypropylene, Polyoxymethylene and Poly (Methyl Methacrylate) Modified with Adhesive Resins

by Jakub Czakaj, Daria Pakuła, Julia Głowacka, Bogna Sztorch and Robert E. Przekop

J. Compos. Sci. 2024, 8(10), 384; https://doi.org/10.3390/jcs8100384 - 24 Sep 2024

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Abstract

Polyoxymethylene (POM), polypropylene (PP), and poly(methyl methacrylate) (PMMA) have been blended with adhesive-grade ethylene vinyl acetate (EVA), propylene elastomer (VMX), isobutylene–isoprene rubber (IIR) and an acrylic block copolymer (MMA-nBA-MMA). The blends were prepared using a two-roll mill and injection molding. The mechanical properties [...] Read more.

Polyoxymethylene (POM), polypropylene (PP), and poly(methyl methacrylate) (PMMA) have been blended with adhesive-grade ethylene vinyl acetate (EVA), propylene elastomer (VMX), isobutylene–isoprene rubber (IIR) and an acrylic block copolymer (MMA-nBA-MMA). The blends were prepared using a two-roll mill and injection molding. The mechanical properties of the blends, such as tensile strength, tensile modulus, elongation at maximum load, and impact resistance, were investigated. The water contact angle, melt flow rate (MFR), and differential scanning calorimetry were ascertained to evaluate the blends. The blend samples exhibited the following properties: all POM/EVA blends showed reduced crystallinity compared to neat POM; the 80% PMMA/20% MMA-nBA-MMA blend showed improved impact resistance by 243% compared to the neat PMMA. An antiplasticization effect was observed for POM/EVA 1% blends and PMMA/EVA 1% blends, with MFR reduced by 1% and 3%, respectively. The MFR of the PP/IIR 1% blend increased by 5%, then decreased below the MFR near the polymer for the remaining IIR concentrations. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 12203 KiB

Open AccessArticle

Elaboration and Experimental Characterizations of Copper-Filled Polyamide Micro-Composites for Tribological Applications

by Mabrouka Akrout, Basma Ben Difallah, Mohamed Kharrat, Maher Dammak, António B. Pereira, Filipe J. Oliveira and Isabel Duarte

J. Compos. Sci. 2024, 8(10), 382; https://doi.org/10.3390/jcs8100382 - 24 Sep 2024

Viewed by 552

Abstract

Polyamide 66 (PA66) has been used for dynamic bearing applications due to its good wear and abrasion resistance, hardness, and rigidity. PA66/copper micro-composites were studied with respect to micro-mechanical, tribological, and structural properties. A mixing step followed by injection molding was used to [...] Read more.

Polyamide 66 (PA66) has been used for dynamic bearing applications due to its good wear and abrasion resistance, hardness, and rigidity. PA66/copper micro-composites were studied with respect to micro-mechanical, tribological, and structural properties. A mixing step followed by injection molding was used to develop the different composites: PA66+5 wt.% Cu, PA66+10 wt.% Cu, and PA66+15 wt.% Cu. The morphological aspects of the composites were studied using scanning electron microscopy and microtomography. Good dispersion and adhesion of Cu particles across the matrix were also seen. DSC analysis showed a slight improvement in the % of crystallinity and thermal characteristics of the composites, particularly with 5 wt.% filler. Additional crystallization enhanced the tensile performance of the composites, including the modulus, elongation at break, and tensile strength. Nanoindentation tests also indicated an increase in indentation hardness and elastic modulus as a function of the filler fraction. A pin-on-disk tribometer was used to study the friction and wear properties of neat PA66 and copper-filled PA66 composites. It was found that the composite with 5 weight percent copper had the best wear resistance. A progressive decrease in the friction coefficient was also seen. Copper filler increases hardness and may effectively reduce the temperature at contact interfaces during rotating cycles. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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10 pages, 2393 KiB

Open AccessArticle

The Effects of Different Blending Methods on the Thermal, Mechanical, and Optical Properties of PMMA/SiO₂ Composites

by Chi-Kai Lin, Jia-Wei Xie, Ping-Jui Tsai, Hao-Yu Wang, Zhi-Wei Lu, Tung-Yi Lin and Chih-Yu Kuo

J. Compos. Sci. 2024, 8(9), 369; https://doi.org/10.3390/jcs8090369 - 20 Sep 2024

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Abstract

In this study, PMMA/SiO₂ composites were fabricated with monodispersed SiO₂ and PMMA using four distinct methods—physical blending, in situ polymerization, random copolymerization, and block copolymerization—to investigate the composites’ thermal, mechanical, and optical properties. In the physical blending approach, SiO₂ nanoparticles [...] Read more.

In this study, PMMA/SiO₂ composites were fabricated with monodispersed SiO₂ and PMMA using four distinct methods—physical blending, in situ polymerization, random copolymerization, and block copolymerization—to investigate the composites’ thermal, mechanical, and optical properties. In the physical blending approach, SiO₂ nanoparticles were dispersed in a PMMA solution, while during in situ polymerization, silica nanoparticles were incorporated during the synthesis of PMMA/SiO₂ composites. 3-methacryloxypropyltrimethoxysilane (MPS) was modified on the SiO₂ surface to introduce the reactive double bonds. The MPS@SiO₂ was either random- or block-copolymerized with PMMA through RAFT polymerization. The PMMA/SiO₂ composites prepared via these different methods were characterized using FTIR, TGA, and DSC to determine their chemical structures, thermal degradation temperatures, and glass transition temperatures, respectively. Scanning electron microscopy (SEM) was employed to observe the microstructures and dispersion of the composites. This comprehensive analysis revealed that the PMMA/SiO₂ composites prepared via block copolymerization exhibited thermal stability at temperatures between 200 and 300 °C. Additionally, they demonstrated excellent transparency (86%) and scratch resistance (≥6H) while maintaining mechanical strength, suggesting their potential application in thermal insulation materials. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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15 pages, 3717 KiB

Open AccessArticle

Bio-Based Polyurethane Composites from Macauba Kernel Oil: Part 1, Matrix Synthesis from Glycerol-Based Polyol

by Rodolfo Andrade Breves, Daniel Ajiola, Roseany de Vasconcelos Vieira Lopes, Rafael L. Quirino, Baptiste Colin, Anelie Petrissans, Mathieu Petrissans and Maria José Araújo Sales

J. Compos. Sci. 2024, 8(9), 363; https://doi.org/10.3390/jcs8090363 - 17 Sep 2024

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Abstract

Polyurethanes are the result of a reaction between an isocyanate and a polyol. The large variety of possible reagents creates many possible polyurethanes to be made, such as soft foams, rigid foams, coatings, and adhesives. This polymer is one of the most produced [...] Read more.

Polyurethanes are the result of a reaction between an isocyanate and a polyol. The large variety of possible reagents creates many possible polyurethanes to be made, such as soft foams, rigid foams, coatings, and adhesives. This polymer is one of the most produced and consumed polymers in the world with an ever-increasing demand. Despite its usual petrochemical nature, research on bio-based polyurethanes flourishes due to the ease in creating bio-based polyols. This work covers the synthesis of a novel macauba kernel oil polyol by the epoxidation of the oil, followed by a ring-opening reaction of the epoxide with glycerol, used for the preparation of polyurethane foams using different NCO/OH ratios. The FTIR and H¹ results confirm the formation of the epoxide and polyol, and the polymers in all NCO/OH ratios were confirmed by FTIR, showing great similarities between the samples, especially PU 1.0 and PU 1.2. Despite the TGs showing close behaviors for the three samples, their DTGs showed great difference between the samples, with PU 1.0 presenting a regular PU DTG profile with three degradation peaks while the other two sample presented five degradation peaks, indicating a higher crosslinking density in them. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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14 pages, 2796 KiB

Open AccessArticle

Pseudocapacitive and Magnetic Properties of SrFe₁₂O₁₉–Polypyrrole Composites

by Michael MacDonald and Igor Zhitomirsky

J. Compos. Sci. 2024, 8(9), 351; https://doi.org/10.3390/jcs8090351 - 7 Sep 2024

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Abstract

This study is inspired by the importance of advanced composites, combining spontaneous magnetization with electrical charge storage properties. It is focused on the investigation of magnetically hard SrFe₁₂O₁₉ (SFO) material and its composites with polypyrrole (PPy). For the first time, [...] Read more.

This study is inspired by the importance of advanced composites, combining spontaneous magnetization with electrical charge storage properties. It is focused on the investigation of magnetically hard SrFe₁₂O₁₉ (SFO) material and its composites with polypyrrole (PPy). For the first time, an organic surfactant–charge transfer mediator and high-energy ball milling (HEBM) were applied to the preparation of high-active-mass SFO composite electrodes. An important finding was the ability to achieve enhanced capacitance of SFO and its composites in a negative range of electrode potentials in an electrolyte. The benefits of the sodium sulfate electrolyte and the charge storage mechanism are discussed. Another important finding was the synergy of the properties of SFO and PPy, which allowed the preparation of highly capacitive conductive composites. The effects of HEBM and the SFO content in the composites on the capacitive properties were studied. Magnetic measurements revealed the effect of HEBM on the magnetic properties and demonstrated good magnetic properties of the composites, which also exhibited advanced capacitive properties. The composites were utilized for the manufacturing of an asymmetric device, which exhibited high capacitive properties at an applied voltage of 1.5 V. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 3653 KiB

Open AccessArticle

Optimized Porous Carbon Particles from Sucrose and Their Polyethyleneimine Modifications for Enhanced CO₂ Capture

by Betul Ari, Erk Inger, Aydin K. Sunol and Nurettin Sahiner

J. Compos. Sci. 2024, 8(9), 338; https://doi.org/10.3390/jcs8090338 - 27 Aug 2024

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Abstract

Carbon dioxide (CO₂), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO₂ capture and storage technologies is of significant [...] Read more.

Carbon dioxide (CO₂), one of the primary greenhouse gases, plays a key role in global warming and is one of the culprits in the climate change crisis. Therefore, the use of appropriate CO₂ capture and storage technologies is of significant importance for the future of planet Earth due to atmospheric, climate, and environmental concerns. A cleaner and more sustainable approach to CO₂ capture and storage using porous materials, membranes, and amine-based sorbents could offer excellent possibilities. Here, sucrose-derived porous carbon particles (PCPs) were synthesized as adsorbents for CO₂ capture. Next, these PCPs were modified with branched- and linear-polyethyleneimine (B-PEI and L-PEI) as B-PEI-PCP and L-PEI-PCP, respectively. These PCPs and their PEI-modified forms were then used to prepare metal nanoparticles such as Co, Cu, and Ni in situ as M@PCP and M@L/B-PEI-PCP (M: Ni, Co, and Cu). The presence of PEI on the PCP surface enables new amine functional groups, known for high CO₂ capture ability. The presence of metal nanoparticles in the structure may be used as a catalyst to convert the captured CO₂ into useful products, e.g., fuels or other chemical compounds, at high temperatures. It was found that B-PEI-PCP has a larger surface area and higher CO₂ capture capacity with a surface area of 32.84 m²/g and a CO₂ capture capacity of 1.05 mmol CO₂/g adsorbent compared to L-PEI-PCP. Amongst metal-nanoparticle-embedded PEI-PCPs (M@PEI-PCPs, M: Ni, Co, Cu), Ni@L-PEI-PCP was found to have higher CO₂ capture capacity, 0.81 mmol CO₂/g adsorbent, and a surface area of 225 m²/g. These data are significant as they will steer future studies for the conversion of captured CO₂ into useful fuels/chemicals. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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12 pages, 2826 KiB

Open AccessArticle

Water Diffusion in Additively Manufactured Polymers: Effect of Voids

by Boyu Li, Konstantinos P. Baxevanakis and Vadim V. Silberschmidt

J. Compos. Sci. 2024, 8(8), 319; https://doi.org/10.3390/jcs8080319 - 12 Aug 2024

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Abstract

This study investigates the effect of void features in additively manufactured polymers on water diffusion, focusing on polyethylene terephthalate glycol (PETG) composites. The additive manufacturing (AM) of polymers, specifically, material extrusion AM (MEAM), results in manufacturing-induced voids, therefore affecting the water resistance of [...] Read more.

This study investigates the effect of void features in additively manufactured polymers on water diffusion, focusing on polyethylene terephthalate glycol (PETG) composites. The additive manufacturing (AM) of polymers, specifically, material extrusion AM (MEAM), results in manufacturing-induced voids, therefore affecting the water resistance of the printed parts. The research analyses the effects of size, shape, orientation and the hydrophilicity of voids on moisture diffusion in PETG composites employing numerical (finite-element) simulations. Two void types were examined: voids of Type I that retard the moisture propagation and voids of Type II that enhance it. Simulations demonstrate that a higher volume fraction of voids and their orientation with regard to the diffusion direction significantly hinder the moisture transport for Type I voids. Conversely, due to their high diffusivity, Type II voids serve as channels for rapid moisture transmission. Consequently, for such materials, the global diffusion rates mainly depend on the volume fraction of voids rather than their shape. These findings indicate the critical role of voids in the design of AM parts for environments exposed to moisture, such as marine and offshore applications. Understanding the void effects is critical for optimising the durability and performance of MEAM components underwater exposure. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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17 pages, 4465 KiB

Open AccessArticle

The Development of Sustainable Polyoxymethylene (POM)-Based Composites by the Introduction of Natural Fillers and Melt Blending with Poly(lactic acid)-PLA

by Anna Soćko and Jacek Andrzejewski

J. Compos. Sci. 2024, 8(8), 315; https://doi.org/10.3390/jcs8080315 - 10 Aug 2024

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Abstract

The conducted study was focused on the development of a new type of technical blend reinforced with natural fillers. The study was divided into two parts, where, in the first stage of the research, unmodified POM was reinforced with different types of natural [...] Read more.

The conducted study was focused on the development of a new type of technical blend reinforced with natural fillers. The study was divided into two parts, where, in the first stage of the research, unmodified POM was reinforced with different types of natural fillers: cellulose, wood flour, and husk particles. In order to select the type of filler intended for further modification, the mechanical characteristics were assessed. The 20% wood flour (WF) filler system was selected as the reinforcement. The second stage of research involved the use of a combination of polyoxymethylene POM and poly(lactic acid) PLA. The POM/PLA blend (ratio 50/50%) was modified with an elastomeric compound (EBA) and chain extender as the compatibilized reactive (CE). The microscopic analysis revealed that for the POM/PLA system, the filler–matrix interface is characterized by better wettability, which might suggest higher adhesion. The mechanical performance revealed that for POM/PLA-based composites, the properties were very close to the results for POM-WF composites; however, there is still a significant difference in thermal resistance in favor of POM-based materials. The increase in thermomechanical properties for POM/PLA composites occurs after heat treatment. The increasing crystallinity of the PLA phase allows for a significant increase in the heat deflection temperature (HDT), even above 125 °C. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 3013 KiB

Open AccessArticle

A Study on the Early Degradation of the Non-Additive Polypropylene–Polyethylene Composite Sampled between the Polymerization Reactor and the Deactivation-Degassing Tank

by Joaquín Alejandro Hernández Fernández, Rodrigo Ortega-Toro and Eduardo Antonio Espinosa Fuentes

J. Compos. Sci. 2024, 8(8), 311; https://doi.org/10.3390/jcs8080311 - 9 Aug 2024

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Abstract

The industrial production of polypropylene–polyethylene composites (C-PP-PE) involves the generation of waste that is not usable, resulting in a significant environmental impact globally. In this research, we identified different concentrations of aluminum (8–410 ppm), chlorine (13–205 ppm), and iron (4–100 ppm) residues originating [...] Read more.

The industrial production of polypropylene–polyethylene composites (C-PP-PE) involves the generation of waste that is not usable, resulting in a significant environmental impact globally. In this research, we identified different concentrations of aluminum (8–410 ppm), chlorine (13–205 ppm), and iron (4–100 ppm) residues originating from traces of the Ziegler–Natta catalyst and the triethylaluminum (TEAL) co-catalyst. These residues accelerate the generation of plastic waste and affect the thermo-kinetic performance of C-PP-PE, as well as the formation of volatile organic compounds that reduce the commercial viability of C-PP-PE. Several families of organic compounds were quantified by gas chromatography with mass spectrometry, and it is evident that these concentrations varied directly with the ppm of Al, Cl, and Fe present in C-PP-PE. This research used kinetic models of Coats–Redfern, Horowitz–Metzger, Flynn–Wall–Ozawa, and Kissinger–Akahira–Sunose. The activation energy values (Ea) were inversely correlated with Al, Cl, and Fe concentrations. In samples PP0 and W3, with low Al, Cl, and Fe concentrations, the values (Ea) were 286 and 224 kJ mol⁻¹, respectively, using the Horowitz method. Samples W1 and W5, with a high ppm of these elements, showed Ea values of 80.83 and 102.99 kJ mol⁻¹, respectively. This knowledge of the thermodynamic behavior and the elucidation of possible chemical reactions in the industrial production of C-PP-PE allowed us to search for a suitable remediation technique to give a new commercial life to C-PP-PE waste, thus supporting the management of plastic waste and improving the process—recycling to promote sustainability and industrial efficiency. One option was using the antioxidant additive Irgafos P-168 (IG-P168), which stabilized some of these C-PP-PE residues very well until thermal properties similar to those of pure C-PP-PE were obtained. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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18 pages, 3939 KiB

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Influence of Additives on Flame-Retardant, Thermal, and Mechanical Properties of a Sulfur–Triglyceride Polymer Composite

by Perla Y. Sauceda-Oloño, Bárbara G. S. Guinati, Ashlyn D. Smith and Rhett C. Smith

J. Compos. Sci. 2024, 8(8), 304; https://doi.org/10.3390/jcs8080304 - 5 Aug 2024

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Abstract

Plastics and composites for consumer goods often require flame retardants (FRs) to mitigate flammability risks. Finding FRs that are effective in new sustainable materials is important for bringing them to the market. This study evaluated various FRs in SunBG₉₀ (a composite made [...] Read more.

Plastics and composites for consumer goods often require flame retardants (FRs) to mitigate flammability risks. Finding FRs that are effective in new sustainable materials is important for bringing them to the market. This study evaluated various FRs in SunBG₉₀ (a composite made from triglycerides and sulfur)—a high sulfur-content material (HSM) promising for use in Li–S batteries, where flame resistance is critical. SunBG₉₀ was blended with FRs from several classes (inorganic, phosphorus-based, brominated, and nitrogen-containing) to assess compliance with UL94 Burning Test standards. Inorganic FRs showed poor flame retardancy and lower mechanical strength, while organic additives significantly improved fire resistance. The addition of 20 wt. % tetrabromobisphenol A enabled SunBG₉₀ to achieve the highest flame retardancy rating (94V-0), while also enhancing wear resistance (52 I_W, ASTM C1353) and bonding strength (26 psi, ASTM C482). Selected organic FRs also enhance compressive strength compared to the FR-free SunBG₉₀. This research highlights the potential of HSMs with traditional FRs to meet stringent fire safety standards while preserving or enhancing the mechanical integrity of HSM composites. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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17 pages, 8611 KiB

Open AccessArticle

Micrographite (μG) and Polypropylene (PP) Composites: Preparation and Influence of Filler Content on Property Modifications

by Rabindra Dharai, Harekrushna Sutar, Rabiranjan Murmu and Debashis Roy

J. Compos. Sci. 2024, 8(8), 298; https://doi.org/10.3390/jcs8080298 - 1 Aug 2024

Viewed by 1352

Abstract

It is difficult to select low-cost filler materials. Specifically, carbon-based filling materials are a matter of concern, and developing a carbon-filled polymer composite with enhanced properties is necessary. In this study, the authors developed a polymer composite using virgin polypropylene (PP) as a [...] Read more.

It is difficult to select low-cost filler materials. Specifically, carbon-based filling materials are a matter of concern, and developing a carbon-filled polymer composite with enhanced properties is necessary. In this study, the authors developed a polymer composite using virgin polypropylene (PP) as a matrix and affordable micrographite (µG) as a filler. The developed composite has many potential applications in the automotive, aerospace, and electronic industries. To prepare the test specimens, the composite was prepared using a twin-screw extruder containing 3, 6, 9, 12, or 15 wt.% µG powder (BET surface area ≈ 29 m²/g; particle size > 50 µm) followed by injection molding. Different mechanical properties like the tensile, flexural, and impact strengths were determined. The prepared composites were further characterized by means of XRD, TGA, DSC, FTIR, DMA, FESEM, and PLM tests. The results were analyzed and compared with those for PP. Improved tensile (up to ≈ 34 MPa) and flexural (up to ≈ 40 MPa) strength was observed with an increase in the µG content. However, the impact strength continuously decreased (maximum ≈ 32 J/m for PP) with fractures. These findings underscore that graphite plays a significant role in controlling the deformation behavior and ultimate strength of composites. An XRD analysis revealed that adding graphite restructured the crystalline arrangement of PP and altered the composite’s crystallographic properties. Nonetheless, no induction effect (β-phase formation) was observed. A moderate enhancement in the thermal stability was observed owing to a small increase in the melt (T_m), onset (T_onset), and residual (T_R) temperatures. A microstructural analysis showed that the micrographite powder strongly prevented spherulite growth and modified the graphite powder’s rate of dispersion and agglomeration in a polymer matrix. The results show that graphite could be a viable low-cost alternative carbon-based filler material in polypropylene matrices. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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17 pages, 7206 KiB

Open AccessArticle

Assessment of Long-Term Water Absorption on Thermal, Morphological, and Mechanical Properties of Polypropylene-Based Composites with Agro-Waste Fillers

by Tatiana Zhiltsova, Andreia Costa and Mónica S. A. Oliveira

J. Compos. Sci. 2024, 8(8), 288; https://doi.org/10.3390/jcs8080288 - 26 Jul 2024

Viewed by 518

Abstract

Agro-waste fibres for polymer composite reinforcement have gained increased interest in industry and academia as a more sustainable alternative to synthetic fibres. However, natural fibre composite (NFC) hygroscopicity is still an issue that needs to be solved. This work investigates how prolonged exposure [...] Read more.

Agro-waste fibres for polymer composite reinforcement have gained increased interest in industry and academia as a more sustainable alternative to synthetic fibres. However, natural fibre composite (NFC) hygroscopicity is still an issue that needs to be solved. This work investigates how prolonged exposure to water affects the properties of the polypropylene (PP)-based injection-moulded composites reinforced with different contents of rice husk (rh) and olive pit (op) fibres. Both rh and op composites became more hydrophilic with increased fibre charge due to the affinity of cellulose and hemicellulose OH groups. Meanwhile, lignin contributes to the protection of the composites from thermo-oxidative degradation caused by water immersion. The PPrh composites had a higher saturation water content of 1.47% (20 wt.% rh) and 2.38% (30 wt.% rh) in comparison to PPop composites with an absorption of 1.13% (20 wt.% op) and 1.59% (30 wt.% op). The tensile elastic modulus has slightly increased, at the cost of the increased saturated composites’ rigidity, in composites with 30% rh and op fibre content (up to 13%) while marginally decreasing (down to 8%) in PP30%op compared to unsaturated counterparts. A similar trend was observed for the flexural modulus, enhanced up to 18%. However, rh and op composites with 30% fibre content ruptured in bending, highlighting their fragility after hydrolytic ageing. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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15 pages, 4366 KiB

Open AccessArticle

Polymer Microspheres Carrying Schiff-Base Ligands for Metal Ion Adsorption Obtained via Pickering Emulsion Polymerization

by Andrei Honciuc, Oana-Iuliana Negru, Mirela Honciuc and Ana-Maria Solonaru

J. Compos. Sci. 2024, 8(7), 271; https://doi.org/10.3390/jcs8070271 - 13 Jul 2024

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Abstract

Several traditional methods for producing polymer microparticle adsorbents for metal ions exist, such as bulk polymerization followed by milling and crushing the material to micron-size particles, precipitation from organic solvents, and suspension polymerization utilizing surfactants. Alternative methods that are easily scalable and are [...] Read more.

Several traditional methods for producing polymer microparticle adsorbents for metal ions exist, such as bulk polymerization followed by milling and crushing the material to micron-size particles, precipitation from organic solvents, and suspension polymerization utilizing surfactants. Alternative methods that are easily scalable and are environmentally friendly are in high demand. This study employs Pickering Emulsion Polymerization Technology (PEmPTech) to synthesize nanostructured polymer microspheres that incorporate Schiff-base ligands, which can be utilized for metal ion adsorption, and specifically Cu(II) ions. Our innovative approach makes use of nanoparticle-stabilized, surfactant-free emulsions/suspensions, enabling the straightforward production of ligand-bearing microspheres while allowing for the precise modulation of the polymer matrix chemistry to maximize adsorption capacities. Through this method, we demonstrate notable enhancements in Cu(II) ion adsorption, which correlates with both the polarity of the monomers used and the concentration of Schiff-base ligands within the microspheres. Notably, our results offer insights into the structure–activity relationships essential for designing tailored adsorbents. This work provides a scalable method to produce high-performance adsorbents and also contributes to sustainable methodologies by excluding harmful surfactants and solvents. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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23 pages, 12190 KiB

Open AccessArticle

Effect of PVDF, HA, and AgNO₃ Annealing on β-Phase, Optical, and Mechanical Properties

by Ieva Markuniene, Arvydas Palevicius, Joris Vezys, Jakub Augustyniak, Dariusz Perkowski, Sigita Urbaite and Giedrius Janusas

J. Compos. Sci. 2024, 8(7), 240; https://doi.org/10.3390/jcs8070240 - 25 Jun 2024

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Abstract

Typically, polymer composites and ceramics are used to create biosensors. Materials with properties that are ideal for biosensors and chemical sensors include AgNO₃ (silver nitrate), PVDF (polyvinylidene fluoride), and HA (hydroxyapatite). Polyvinylidene fluoride (PVDF) polymer has been widely used in several applications [...] Read more.

Typically, polymer composites and ceramics are used to create biosensors. Materials with properties that are ideal for biosensors and chemical sensors include AgNO₃ (silver nitrate), PVDF (polyvinylidene fluoride), and HA (hydroxyapatite). Polyvinylidene fluoride (PVDF) polymer has been widely used in several applications because of its well-known superior ferroelectric characteristics and biocompatibility. The brittleness and low bending strength of hydroxyapatite limit its applicability. Several HA and polymer composite formulations have been developed to compensate for HA’s mechanical weakness. The final product contains a significant amount of HA, making HA/polymer composites highly biocompatible. When the right amount of silver is deposited, the maximum piezoelectric activity is generated, and silver nitrate has antimicrobial properties. The non-toxic solvent DMSO (dimethyl sulfoxide) and the solvent casting method were chosen for the preparation of the film. Surface roughness was chosen to measure the Str and Sdr properties of the thin film. For liquid preparation, the multifractal spectra analysis was chosen for each sample. SEM was used to examine the samples morphologically. EDX and mapping analyses were presented for chemistry distribution in the samples. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 11971 KiB

Open AccessArticle

Development and Evaluation of 3D-Printed PLA/PHA/PHB/HA Composite Scaffolds for Enhanced Tissue-Engineering Applications

by Motahareh Sadat Raziyan, Arvydas Palevicius, Dariusz Perkowski, Sigita Urbaite and Giedrius Janusas

J. Compos. Sci. 2024, 8(6), 226; https://doi.org/10.3390/jcs8060226 - 16 Jun 2024

Cited by 1 | Viewed by 1141

Abstract

Recently, tissue engineering has been revolutionised by the development of 3D-printed scaffolds, which allow one to construct a precise architecture with tailored properties. In this study, three different composite materials were synthesised using a combination of polylactic acid (PLA), polyhydroxyalkanoates (PHA), poly(3-hydroxybutyrate) (PHB) [...] Read more.

Recently, tissue engineering has been revolutionised by the development of 3D-printed scaffolds, which allow one to construct a precise architecture with tailored properties. In this study, three different composite materials were synthesised using a combination of polylactic acid (PLA), polyhydroxyalkanoates (PHA), poly(3-hydroxybutyrate) (PHB) and hydroxyapatite (HA) in varying weight percentages. Morphological properties were evaluated by scanning electron microscopy showing a uniform distribution of HA particles throughout the matrix, indicating good compatibility between the materials. Furthermore, the printed scaffolds were tested under pressure using a load cell to examine mechanical strength. Scanning electron microscopy (SEM) analysis showed favorable dispersion, biological compatibility together with enhanced bioactivity within the PHB/PHA/PLA/HA composite matrixes. Thus, this paper demonstrates the successful design and implementation of these composite structures for tissue-engineering applications and highlights the effective development of biocompatible scaffold designs with improved functionality. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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14 pages, 27807 KiB

Open AccessArticle

Development of High-Sensitivity Thermoplastic Polyurethane/Single-Walled Carbon Nanotube Strain Sensors through Solution Electrospinning Process Technique

by Athanasios Kotrotsos, Nikolaos Syrmpopoulos, Prokopios Gavathas, Sorina Moica and Vassilis Kostopoulos

J. Compos. Sci. 2024, 8(6), 213; https://doi.org/10.3390/jcs8060213 - 6 Jun 2024

Viewed by 1480

Abstract

In this study, nanofibers obtained through the electrospinning process are explored for strain-sensing applications. Thermoplastic polyurethane (TPU) flexible structures were fabricated using the solution electrospinning process (SEP) technique. Subsequently, these structures were nanomodified with single-walled carbon nanotubes (SWCNTs) through immersion into an ultrasonicated [...] Read more.

In this study, nanofibers obtained through the electrospinning process are explored for strain-sensing applications. Thermoplastic polyurethane (TPU) flexible structures were fabricated using the solution electrospinning process (SEP) technique. Subsequently, these structures were nanomodified with single-walled carbon nanotubes (SWCNTs) through immersion into an ultrasonicated suspension containing 0.3 wt% SWCNTs. The nanomodification aimed to impart an electrically conductive network to the structures. Micro-tensile tests and electrical resistance measurements were conducted to characterize the apparent mechanical and electrical properties, respectively. The fabricated structures demonstrated potential as wearable strain sensors for monitoring changes in strain across various applications. The samples exhibited excellent performance, high sensitivity, outstanding mechanical properties, and a broad stretching range. Scanning electron microscopy (SEM) observations provided qualitative insights into the activated conductive pathways during operation. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 6310 KiB

Open AccessArticle

Valorization of Cork and High-Density Polyethylene and Polypropylene Wastes in Cork–Plastic Composites: Their Morphology, Mechanical Performance, and Fire Properties

by Svetlana Petlitckaia, Virginie Tihay-Felicelli, Laurent Ferry, Sylvain Buonomo, Camille Luciani, Yann Quilichini, Paul-Antoine Santoni, Elisabeth Pereira and Toussaint Barboni

J. Compos. Sci. 2024, 8(6), 195; https://doi.org/10.3390/jcs8060195 - 22 May 2024

Viewed by 936

Abstract

The recycling of waste materials is a way of limiting over-consumption and optimizing the value of resources. Within the framework of a circular economy, this can be applied to post-consumer plastic wastes, but also to biobased by-products. Hence, this work deals with the [...] Read more.

The recycling of waste materials is a way of limiting over-consumption and optimizing the value of resources. Within the framework of a circular economy, this can be applied to post-consumer plastic wastes, but also to biobased by-products. Hence, this work deals with the design of composite materials by combining recycled high-density polyethylene (HDPE) and polypropylene (PP) coming from bottle caps and virgin cork of insufficient quality for cork stoppers. Different fractions (0, 5, 10, 15, and 20 wt%) of virgin cork were incorporated into recycled polymers (HDPE_r and PP_r). These composites were prepared without a coupling agent or fire retardant. The morphology and mechanical properties of the different conditionings were studied and compared. The thermal decomposition and the fire behavior of the composites were also investigated. Microscopy revealed the poor adhesion between the cork particles and polymer matrices. However, this limited interaction affected only the tensile strength of the PP_r composites, while that of the HDPE_r composites remained almost constant. The addition of cork was shown to reduce the time to ignition, but also to promote charring and reduce the heat released during the composite’s combustion. The feasibility of composites based on cork and HDPE_r/PP_r waste opens the way for their reuse. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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10 pages, 1999 KiB

Open AccessCommunication

Properties of Composites Based on Polylactide Filled with Cork Filler

by Mariusz Fabijański

J. Compos. Sci. 2024, 8(5), 185; https://doi.org/10.3390/jcs8050185 - 16 May 2024

Viewed by 1244

Abstract

Introducing fillers into polymeric materials is one of the methods of modifying the properties or reducing the costs of polymeric materials. Thanks to their use, it is possible to obtain new materials with interesting mechanical and chemical properties. Some features are often improved [...] Read more.

Introducing fillers into polymeric materials is one of the methods of modifying the properties or reducing the costs of polymeric materials. Thanks to their use, it is possible to obtain new materials with interesting mechanical and chemical properties. Some features are often improved among the new materials obtained, while others deteriorate. In this work, an attempt was made to obtain a polymer composite based on PLA filled with cork flour in amounts of 5%, 10%, 15%, 20% and 30% by weight. The processing and sample preparation process using injection molding technology was assessed and the basic mechanical properties were assessed. The research shows that it is possible to obtain PLA products with a cork filler without the mixing process on an extruder, but only by using an injection molding machine and appropriately selecting the parameters of the technological process. Tests of mechanical properties showed deterioration of parameters, but not to such an extent that the obtained composites were disqualified from use in products that are not subject to heavy mechanical loads. The undoubted advantage of the obtained materials is maintaining their so-called “green” character and thus the ability to biodegrade. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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16 pages, 2790 KiB

Open AccessArticle

Development of New Polyimide/Spirulina Hybrid Materials: Preparation and Characterization

by Magdalena Aflori, Diana Serbezeanu, Alina Mirela Ipate, Adina Maria Dobos and Daniela Rusu

J. Compos. Sci. 2024, 8(5), 178; https://doi.org/10.3390/jcs8050178 - 12 May 2024

Cited by 2 | Viewed by 1100

Abstract

This study presents the synthesis and characterization of polyimide (PI-2) films incorporated with spirulina powder for potential biomedical applications. The synthesis of PI-2 was achieved through a two-step polycondensation reaction using N-methyl-2-pyrrolidone (NMP) as the solvent. The incorporation of spirulina was systematically varied [...] Read more.

This study presents the synthesis and characterization of polyimide (PI-2) films incorporated with spirulina powder for potential biomedical applications. The synthesis of PI-2 was achieved through a two-step polycondensation reaction using N-methyl-2-pyrrolidone (NMP) as the solvent. The incorporation of spirulina was systematically varied to investigate its effects on the structural and surface properties of the hybrid materials. Scanning electron microscopy revealed a tightly bound interface between spirulina and the PI-2 matrix, indicating effective dispersion and strong interfacial adhesion. Profilometry and Raman spectroscopy confirmed the homogeneous integration of spirulina within the polymer matrix, with resulting variations in surface roughness and chemistry. Contact angle measurements demonstrated altered wettability characteristics, with increased hydrophilicity observed with spirulina incorporation. Furthermore, blood component interaction studies indicated the variations in adhesion behavior observed for red blood cells, platelets, and plasma proteins. Water uptake studies revealed enhanced absorption capacity in PI-2 films loaded with spirulina, highlighting their potential suitability for applications requiring controlled hydration. Overall, this comprehensive characterization elucidates the potential of PI-2/spirulina hybrid materials for diverse biomedical applications, offering tunable properties that can be tailored to specific requirements. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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11 pages, 2756 KiB

Open AccessArticle

A Mechanical Model for Stress Relaxation of Polylactic Acid/Thermoplastic Polyurethane Blends

by Yi-Sheng Jhao, Hao Ouyang, Chien-Chao Huang, Fuqian Yang and Sanboh Lee

J. Compos. Sci. 2024, 8(5), 169; https://doi.org/10.3390/jcs8050169 - 1 May 2024

Cited by 1 | Viewed by 1198

Abstract

Polylactic acid (PLA) is considered a promising biodegradable polymer alternative. Due to its high brittleness, composite materials made by melt blending thermoplastic polyurethane (TPU) with PLA can enhance the toughness of PLA. To understand the forced aging caused by stress relaxation in polymer [...] Read more.

Polylactic acid (PLA) is considered a promising biodegradable polymer alternative. Due to its high brittleness, composite materials made by melt blending thermoplastic polyurethane (TPU) with PLA can enhance the toughness of PLA. To understand the forced aging caused by stress relaxation in polymer materials, this study explains the stress relaxation experiments of PLA/TPU blends with different mass ratios under applied strain through mechanical model simulations. The Kelvin representation of the standard linear solid model (SLSM) is used to analyze the stress relaxation data of TPU/PLA blends, successfully explaining that the Young’s moduli (E₁ and E₂) of springs decrease with increasing temperature and TPU content. The viscosity coefficient of the PLA/TPU blends decreases with increasing temperature, and its reciprocal follows the Arrhenius law. For TPU/PLA blends with increased concentration of TPU, the activation energy for stress relaxation shows a linear decrease, confirmed by the glass transition point measured by DMA, indicating that it does not involve chemical reactions. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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21 pages, 9529 KiB

Open AccessArticle

Quantification of Irgafos P-168 and Degradative Profile in Samples of a Polypropylene/Polyethylene Composite Using Microwave, Ultrasound and Soxhlet Extraction Techniques

by Joaquín Hernández-Fernández, Jaime Pérez-Mendoza and Rodrigo Ortega-Toro

J. Compos. Sci. 2024, 8(4), 156; https://doi.org/10.3390/jcs8040156 - 21 Apr 2024

Cited by 1 | Viewed by 1706

Abstract

In polypropylene/polyethylene composite (C-PP/PE) production, stabilizing additives such as Irgafos P-168 are essential as antioxidant agents. In this study, an investigation was carried out that covers different solid–liquid extraction methods (Soxhlet, ultrasound, and microwaves); various variables were evaluated, such as temperature, extraction time, [...] Read more.

In polypropylene/polyethylene composite (C-PP/PE) production, stabilizing additives such as Irgafos P-168 are essential as antioxidant agents. In this study, an investigation was carried out that covers different solid–liquid extraction methods (Soxhlet, ultrasound, and microwaves); various variables were evaluated, such as temperature, extraction time, the choice of solvents, and the type of C-PP/PE used, and the gas chromatography coupled to mass spectrometry (GC-MS) technique was used to quantify the presence of Irgafos P-168 in the C-PP/PE samples. The results revealed that microwave extraction was the most effective in recovering Irgafos P-168. A recovery of 96.7% was achieved when using dichloromethane as a solvent, and 92.83% was achieved when using limonene as a solvent. The ultrasound technique recovered 91.74% using dichloromethane and 89.71% using limonene. The Soxhlet extraction method showed the lowest recovery percentages of 57.39% using dichloromethane as a solvent and 55.76% with limonene, especially when the C-PP/PE was in the form of pellets. The degradation products that obtained the highest degradation percentages were Bis (di-test-butyl phenyl) phosphate and Mono (di-test-butyl phenyl) phosphate using the microwave method with dichloromethane as a solvent and PP in film. Finally, the possible mechanisms for forming the degradation compounds of Irgafos P-168 were postulated. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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12 pages, 3034 KiB

Open AccessArticle

Tailoring Basalt Fibers and E-Glass Fibers as Reinforcements for Increased Impact Resistance

by Elango Natarajan, Santhosh Mozhuguan Sekar, Kalaimani Markandan, Chun Kit Ang and Gérald Franz

J. Compos. Sci. 2024, 8(4), 137; https://doi.org/10.3390/jcs8040137 - 9 Apr 2024

Cited by 1 | Viewed by 1609

Abstract

The usage of basalt fiber in the engineering industries has gained significant interest due to its characteristics such as alkali resistance and enhanced mechanical properties. Similarly, E-glass-fiber-reinforced composites have been widely used in the fabrication of electrically resistive industrial components such as switches, [...] Read more.

The usage of basalt fiber in the engineering industries has gained significant interest due to its characteristics such as alkali resistance and enhanced mechanical properties. Similarly, E-glass-fiber-reinforced composites have been widely used in the fabrication of electrically resistive industrial components such as switches, circuit panels, and covering cases. In the present study, the tensile, flexural, thermogravimetric, and low-velocity impact characteristics of various percentages of basalt/E-glass-fiber-reinforced polymer composites fabricated via vacuum-assisted resin transfer molding were investigated. The results show that a higher volume percentage of basalt (39%) significantly enhances the impact resistance up to 45% with a moderate improvement in flexural properties. The higher the vol % of E-glass (40%), the more the tensile and flexural properties are increased, i.e., 185 N/mm² and 227.87 N/mm², respectively. It is concluded that by choosing the optimum hybridization method, impact resistance and other mechanical properties can be improved significantly. The thermogravimetric analysis results show that PC313534 (35 vol % basalt and 34 vol % E-glass) possesses the lowest decomposition temperature of 381.10 °C. The results from the present study indicate that the polymer composite fabricated in the present study is suitable for applications where higher structural-load-resistive properties are required. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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18 pages, 9745 KiB

Open AccessArticle

The Polyurethane-Polystyrene Composite—Influence of the Blowing Agent Type on the Foaming Process, the Structure and the Properties

by Elżbieta Malewska, Aleksander Prociak, Natalia Świdzińska-Grela and Maria Kurańska

J. Compos. Sci. 2024, 8(4), 135; https://doi.org/10.3390/jcs8040135 - 5 Apr 2024

Viewed by 3517

Abstract

In this study, polyurethane-polystyrene composites (RPURF-EPS) were obtained with the co-expansion method. This method consists of utilizing the heat of the exothermic reaction of polyurethane (PUR) formation to expand polystyrene beads (PSBs). The materials were obtained using polyurethane systems based on the selected [...] Read more.

In this study, polyurethane-polystyrene composites (RPURF-EPS) were obtained with the co-expansion method. This method consists of utilizing the heat of the exothermic reaction of polyurethane (PUR) formation to expand polystyrene beads (PSBs). The materials were obtained using polyurethane systems based on the selected blowing agents, such as cyclopentane, a mixture of fluorocarbons and water. The analysis of the foaming process was carried out using a special device called FOAMAT. The characteristic start, rise, gelation and curing times were defined. The rise profile, the reaction temperature, the pressure and the dielectric polarization were measured. The influence of selected blowing agents on the cell structure and physical–mechanical properties of reference rigid polyurethane foam (RPURF) and RPURF-EPS, such as apparent density, compressive strength and thermal conductivity, were evaluated. Based on the research, the blowing agents that have the most beneficial influence on the properties and structure of the composites and that provide the most efficient expansion of PSBs in a light porous composite were found. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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14 pages, 8261 KiB

Open AccessArticle

Surface-Modified Wheat Straw for the Production of Cement-Free Geopolymer Composite: Effects of Wheat Variety and Pre-Treatment Method

by Regina Kalpokaitė-Dičkuvienė, Inna Pitak, Anastasiia Sholokhova, Rita Kriūkienė and Arūnas Baltušnikas

J. Compos. Sci. 2024, 8(4), 116; https://doi.org/10.3390/jcs8040116 - 22 Mar 2024

Cited by 2 | Viewed by 1437

Abstract

The development of new composite materials with specific properties and reduced environmental pollution can be achieved by the incorporation of agricultural residues, whose morphology is strongly affected by their variety and growing conditions. Herein, the functional properties of a cement-free geopolymer composite reinforced [...] Read more.

The development of new composite materials with specific properties and reduced environmental pollution can be achieved by the incorporation of agricultural residues, whose morphology is strongly affected by their variety and growing conditions. Herein, the functional properties of a cement-free geopolymer composite reinforced with straw from two wheat varieties (Ada and Malibu) were investigated through different straw pre-treatment methods and their surface modification with silane coupling agents. The characterization of the wheat surface and the geopolymer composites involved SEM-EDS, TGA, FTIR, and gas physisorption analysis methods supplemented with mechanical strength and moisture ingress measurements. Mild (23 °C) and severe (100 °C) physical pre-treatment methods with chemical soaking in 7.3 M isopropanol solution were applied on wheat straw. Tetraethoxysilane (TEOS) with octadecylamine was employed for chemical surface modification. The set of geopolymer compositions was prepared with untreated, pre-treated, and modified straws. The results revealed the hot pre-treatment method caused a higher degradation of siliceous layers of straw, especially in the Ada variety. The modification with TEOS resulted in irregular silane coating formation regardless of the wheat variety and pre-treatment method. Despite good interfacial bonding of the modified straw with the geopolymer matrix, the mechanical strength of the composites was reduced, although the resistance to water ingress slightly increased. Comparing both varieties, Ada wheat showed better performance than Malibu. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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18 pages, 4018 KiB

Open AccessArticle

Polymer Composites of Low-Density Polyethylene (LDPE) with Elongated Hematite (α-Fe₂O₃) Particles of Different Shapes

by Ljerka Kratofil Krehula, Ana Peršić, Nina Popov and Stjepko Krehula

J. Compos. Sci. 2024, 8(2), 73; https://doi.org/10.3390/jcs8020073 - 11 Feb 2024

Cited by 2 | Viewed by 1763

Abstract

Due to the intensive search for new types of advanced polymer materials for targeted applications, this work offers insight into the properties of low-density polyethylene/hematite composites. The specific feature of this study lies in the use of elongated hematite particles of different shapes. [...] Read more.

Due to the intensive search for new types of advanced polymer materials for targeted applications, this work offers insight into the properties of low-density polyethylene/hematite composites. The specific feature of this study lies in the use of elongated hematite particles of different shapes. Uniform ellipsoid-, peanut- and rod-shaped hematite particles were hydrothermally synthesized and incorporated into the polymer matrix of low-density polyethylene (LDPE). LDPE/hematite composites are prepared by melt mixing. Hematite particles are characterized by scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD). The pure LDPE polymer and LDPE/hematite composites were studied by FT-IR and UV-Vis-NIR spectroscopy and by thermogravimetric analysis (TGA). The determination of the mechanical and barrier properties was also carried out. The obtained results indicate the influence of the elongated particles on the improvement of LDPE properties. An increase in thermal stability and UV-absorption was observed as well as the improvement of mechanical and barrier properties. The improvement of the composites’ properties in comparison to the pure LDPE is especially visible in the composites prepared with low content of hematite (0.25%). LDPE/hematite composites have promising characteristics for application as packaging materials with enhanced mechanical, thermal and barrier properties as well as UV-protective materials. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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21 pages, 4649 KiB

Open AccessArticle

Kaolin–Polyvinyl Alcohol–Potato Starch Composite Films for Environmentally Friendly Packaging: Optimization and Characterization

by Noshabah Tabassum, Uzaira Rafique, Maria Qayyum, Abdallah A. A. Mohammed, Saira Asif and Awais Bokhari

J. Compos. Sci. 2024, 8(1), 29; https://doi.org/10.3390/jcs8010029 - 11 Jan 2024

Cited by 3 | Viewed by 2436

Abstract

This research paper introduces an innovative methodology to produce biodegradable composite films by combining kaolin, polyvinyl alcohol (PVA), and potato starch (PS) using a solvent casting technique. The novelty of this study resides in the identification and implementation of optimal synthesis conditions, which [...] Read more.

This research paper introduces an innovative methodology to produce biodegradable composite films by combining kaolin, polyvinyl alcohol (PVA), and potato starch (PS) using a solvent casting technique. The novelty of this study resides in the identification and implementation of optimal synthesis conditions, which were achieved by utilizing the Response Surface Methodology—Central Composite Design. The study defines starch, polyvinyl alcohol (PVA), and kaolin as independent variables and examines their influence on important mechanical qualities, water absorption capacity, moisture content, and degradability as primary outcomes. The study establishes the ideal parameters as 5.5 weight percent Kaolin, 2.5 g of starch, and 3.5 g of PVA. These settings yield notable outcomes, including a tensile strength of 26.5 MPa, an elongation at break of 96%, a water absorption capacity of 21%, a moisture content of 3%, and a remarkable degradability of 48%. The study emphasizes that the augmentation of kaolin content has a substantial impact on many properties, including degradability, tensile strength, and elongation at break. Simultaneously, it leads to a reduction in the water absorption capacity and moisture content. The study’s novelty is reinforced by conducting an additional examination on the ideal composite film, which includes investigations using FTIR, TGA, and SEM-EDX techniques. The consistency between the predicted and experimental results is noteworthy, as it provides further validation for the prediction accuracy of Design Expert software’s quadratic equations. These equations effectively capture the complex interactions that exist between process parameters and selected responses. This study presents novel opportunities for the extensive utilization of PVA/PS composite films, including kaolin in various packaging scenarios, thereby significantly advancing sustainable packaging alternatives. The statistical analysis provides strong evidence supporting the relevance of the models, hence increasing our level of trust in the software’s prediction skills. This conclusion is based on a 95% confidence level and p-values that are below a threshold of 0.05. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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18 pages, 5588 KiB

Open AccessArticle

Fabrication and Characterization of Hollow Polysiloxane Microsphere Polymer Matrix Composites with Improved Energy Absorption

by Sofia Gabriela Gomez, Andrea Irigoyen, Stephanie Gonzalez, Kevin Estala-Rodriguez, Evgeny Shafirovich, Md Sahid Hassan, Saqlain Zaman and Yirong Lin

J. Compos. Sci. 2023, 7(3), 98; https://doi.org/10.3390/jcs7030098 - 4 Mar 2023

Cited by 2 | Viewed by 1657

Abstract

Hollow polymer microspheres with superior elastic properties, high thermal stability, and energy absorbance capabilities are essential in many applications where shock and vibration need to be mitigated, such as in civil, medical, and defense industries. In this paper, the synthesis, fabrication, and characterization [...] Read more.

Hollow polymer microspheres with superior elastic properties, high thermal stability, and energy absorbance capabilities are essential in many applications where shock and vibration need to be mitigated, such as in civil, medical, and defense industries. In this paper, the synthesis, fabrication, and characterization of hollow thermoset microspheres for syntactic polymer foam were studied. The hollow polymer microspheres (HPMs) were made by developing core–shell composites and thermally removing the polystyrene core to yield a polysiloxane shell. The HPMs were embedded into a polydimethylsiloxane (PDMS) matrix to form a polymer syntactic foam. The mechanical energy absorption characteristic of polymer syntactic foams was measured by cyclic uniaxial compression testing following ASTM 575. The engineered compression response was demonstrated by fabricating and testing syntactic foams with different porosities, ranging from a 50 vol% to 70 vol% of HPMs. Through scanning electron microscopy (SEM), we observed that the HPM contributes to the energy absorption of the syntactic foam. Moreover, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) determined the necessity of a profound study to understand the effects of varying HPM synthesis parameters, as well as the syntactic foam fabrication methods. It was shown that the compressive modulus and toughness can be increased by 20% using a 70 vol% of porosity with synthesized HPM syntactic foams over bulk PDMS. We also found that the energy absorbed increased by 540% when using a 50 vol% of porosity with fabricated HPM-PDMS syntactic foams. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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Review

Jump to: Research

26 pages, 3403 KiB

Open AccessReview

Current Trends in the Use of Biomass in the Manufacture of Rigid Polyurethane Foams: A Review

by Dorota Dukarska and Radosław Mirski

J. Compos. Sci. 2024, 8(8), 286; https://doi.org/10.3390/jcs8080286 - 23 Jul 2024

Cited by 2 | Viewed by 1061

Abstract

This paper discusses methods of using biomass from the agriculture, forestry, food and aquaculture industries as potential raw materials for bio-polyols and as fillers in the production of rigid polyurethane (RPUR) foams. Various aspects of obtaining bio-polyols are discussed, as well as the [...] Read more.

This paper discusses methods of using biomass from the agriculture, forestry, food and aquaculture industries as potential raw materials for bio-polyols and as fillers in the production of rigid polyurethane (RPUR) foams. Various aspects of obtaining bio-polyols are discussed, as well as the impact of replacing petrochemical polyols with bio-polyols on the properties of foams. Special attention is paid to the conversion of vegetable oils and lignin. Another important aspect of the research is the use of biomass as foam fillers. Chemical and physical modifications are discussed, and important factors, such as the type and origin of biomass, particle size and amount, affecting the foaming process, microstructure and properties of RPUR foams are identified. The advantages and disadvantages of using biomass in foam production are described. It is found that bio-polyols can replace (at least partially) petrochemical polyols while maintaining the high insulation and strength of foams. In the case of the use of biomass as fillers, it is found that the shaping of their properties is largely dependent on the specific characteristics of the filler particles. This requires further research into process optimization but allows for the fine-tuning of RPUR foam properties to meet specific requirements. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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18 pages, 1222 KiB

Open AccessReview

A Critical Review of Cold-Formed Steel Built-Up Composite Columns with Geopolymer Concrete Infill

by Serene Sara Simon, Bidur Kafle and Riyadh Al-Ameri

J. Compos. Sci. 2024, 8(7), 238; https://doi.org/10.3390/jcs8070238 - 24 Jun 2024

Viewed by 1097

Abstract

Concrete-filled built-up cold-formed steel (CFS) columns offer enhanced load-carrying capacity, improved strength-to-weight ratios, and delayed buckling through providing internal resistance and stiffness due to the concrete infill. Integrating sustainable alternatives like self-compacting geopolymer concrete (SCGC) with low carbon emissions is increasingly favoured for [...] Read more.

Concrete-filled built-up cold-formed steel (CFS) columns offer enhanced load-carrying capacity, improved strength-to-weight ratios, and delayed buckling through providing internal resistance and stiffness due to the concrete infill. Integrating sustainable alternatives like self-compacting geopolymer concrete (SCGC) with low carbon emissions is increasingly favoured for addressing environmental concerns in construction. This review aims to explore the current knowledge regarding CFS built-up composite columns and the performance of SCGC within them. While research on geopolymer concrete-filled steel tubes (GPCFSTs) under various loads has demonstrated high strength and ductility, investigations into built-up sections remain limited. The literature suggests that geopolymer concrete’s superior compressive strength, fire resistance, and minimal shrinkage render it highly compatible with steel tubular columns, providing robust load-bearing capacity and gradual post-ultimate strength, attributed to the confinement effect of the outer steel tubes, thereby preventing brittle failure. Additionally, in built-up sections, connector penetration depth and spacing, particularly at the ends, enhances structural performance through composite action in CFS structures. Consequently, understanding the importance of using a sustainable and superior infill like SCGC, the cross-sectional efficiency of CFS sections, and optimal shear connections in built-up CFS columns is crucial. Moreover, there is a potential for developing environmentally sustainable built-up CFS composite columns using SCGC cured at ambient temperatures as infill. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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23 pages, 10540 KiB

Open AccessReview

Unveiling the Influential Factors and Heavy Industrial Applications of Graphene Hybrid Polymer Composites

by Zulfiqar Ali, Saba Yaqoob, Jinhong Yu and Alberto D’Amore

J. Compos. Sci. 2024, 8(5), 183; https://doi.org/10.3390/jcs8050183 - 13 May 2024

Cited by 1 | Viewed by 1382

Abstract

Graphene hybrid-filler polymer composites have emerged as prominent materials that revolutionize heavy industries. This review paper encapsulates an in-depth analysis of different influential factors, such as filler/graphene type, aspect ratios, dispersion methods, filler-matrix compatibility, fiber orientation, synergistic effects, different processing techniques, and post-curing [...] Read more.

Graphene hybrid-filler polymer composites have emerged as prominent materials that revolutionize heavy industries. This review paper encapsulates an in-depth analysis of different influential factors, such as filler/graphene type, aspect ratios, dispersion methods, filler-matrix compatibility, fiber orientation, synergistic effects, different processing techniques, and post-curing conditions, which affect the processing and properties of graphene hybrid polymer composites, as well as their resultant applications. Additionally, it discusses the substantial role of graphene reinforcement with other fillers, such as carbon nanotubes, silica, nano-clays, and metal oxides, to produce functionalized hybrid polymer composites with synergistically enhanced tailored properties, offering solutions for heavy industries, including aerospace, automotive, electronics, and energy harvesting. This review concludes with some suggestions and an outlook on the future of these composite materials by emphasizing the need for continued research to fully optimize their potential. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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36 pages, 7429 KiB

Open AccessReview

Structure, Properties, and Recent Developments in Polysaccharide- and Aliphatic Polyester-Based Packaging—A Review

by Wasana N. Marasinghe, K. G. L. R. Jayathunge, Rohan S. Dassanayake, Rumesh Liyanage, Pasan C. Bandara, Suranga M. Rajapaksha and Chamila Gunathilake

J. Compos. Sci. 2024, 8(3), 114; https://doi.org/10.3390/jcs8030114 - 21 Mar 2024

Cited by 2 | Viewed by 2216

Abstract

Food packaging plays an imperative role in the food processing sector by safeguarding foods from their point of harvesting until the moment of consumption. In recent years, biopolymers have attracted the attention of the scientific community as an alternative to conventional packaging materials. [...] Read more.

Food packaging plays an imperative role in the food processing sector by safeguarding foods from their point of harvesting until the moment of consumption. In recent years, biopolymers have attracted the attention of the scientific community as an alternative to conventional packaging materials. Among the available biopolymer sources, a lot of the focus has been on polysaccharides due to their superior barrier properties against gases, oils, and odors and their processing versatility. Moreover, there is also a growing interest in aliphatic polyester as a potential replacement for petrochemical-based synthetic plastics. Both polysaccharides and aliphatic polyesters have gained popularity in sustainable food packaging due to their unique characteristics, including their low cost, availability, biodegradability, gas and moisture barrier properties, film-forming capabilities, excellent heat resistance, and ability to be processed into films, trays, and coatings. This review highlights the structural features, properties, and recent advancements of several vital polysaccharides, namely, starch, chitosan, cellulose, alginate, pectin, carrageenan, and aliphatic polyesters, including polylactic acid (PLA) and polyhydroxybutyrate (PHB) for developing packaging materials, and their applications in the food industry. Conventional packaging and future perspectives of biopolymer-based food packaging are also comprehensively covered in this review. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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17 pages, 882 KiB

Open AccessReview

Polylactic Acid Polymer Matrix (Pla) Biocomposites with Plant Fibers for Manufacturing 3D Printing Filaments: A Review

by Victor Hugo M. Almeida, Raildo M. Jesus, Gregório M. Santana and Thaís B. Pereira

J. Compos. Sci. 2024, 8(2), 67; https://doi.org/10.3390/jcs8020067 - 9 Feb 2024

Cited by 6 | Viewed by 2518

Abstract

The escalating global demand for polymer products and the consequent disposal challenge necessitate technological and sustainable solutions. Recent advances in the development of materials used in 3D printing equipment are described in this review, with a focus on new biocomposite materials. The investigation [...] Read more.

The escalating global demand for polymer products and the consequent disposal challenge necessitate technological and sustainable solutions. Recent advances in the development of materials used in 3D printing equipment are described in this review, with a focus on new biocomposite materials. The investigation delves into biocomposites comprising PLA and its blends with other polymers, reinforced by plant fibers, with a particular focus on research conducted over the last five years. The information related to the raw materials’ physical, chemical, and processing properties necessary for creating biocomposite filament and printed parts were summarized. The best results in terms of tensile and flexural strength were presented and discussed, signposting future research avenues and desirable objectives. The findings elucidate that the inclusion of plant fibers led to a reduction in mechanical strength relative to pure PLA; however, when smaller particle sizes of plant fibers were added in volumes below 10%, it resulted in improved performance. Moreover, physical and/or chemical pretreatment of fibers, along with the isolation of cellulose fibrils, emerged as pivotal strategies for bolstering mechanical strengths. Noteworthy are the promising prospects presented by the incorporation of additives, while the refinement of printing parameters is key to improving the tensile and flexural strength of printed components. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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23 pages, 5605 KiB

Open AccessReview

Recent Advances in pH and Redox Responsive Polymer Nanocomposites for Cancer Therapy

by Shivalingayya Gaddimath, Shivanand Payamalle, Keshavananada Prabhu Channabasavana Hundi Puttaningaiah and Jaehyun Hur

J. Compos. Sci. 2024, 8(1), 28; https://doi.org/10.3390/jcs8010028 - 11 Jan 2024

Cited by 5 | Viewed by 2561

Abstract

Cancer therapy currently focuses on personalized targeted treatments. A promising approach uses stimuli-responsive biomaterials for site-specific drug release, such as pH- and redox-triggered polymer nanocomposites. These materials respond to the tumor microenvironment, enhance efficacy, and reduce off-target effects. Cancer cells with anomalous properties [...] Read more.

Cancer therapy currently focuses on personalized targeted treatments. A promising approach uses stimuli-responsive biomaterials for site-specific drug release, such as pH- and redox-triggered polymer nanocomposites. These materials respond to the tumor microenvironment, enhance efficacy, and reduce off-target effects. Cancer cells with anomalous properties such as acidic cytosolic pH and elevated redox potential are targeted by these biomaterials. An imbalance in ions and biological thiols in the cytoplasm contributes to tumor growth. Functionalized polymer nanocomposites with large surface areas and specific targeting outperform conventional small-molecule materials. To overcome problems such as low bioavailability, uncontrolled drug release, and poor cell penetration, multifunctional nanomaterials make it easier for drugs to enter certain cellular or subcellular systems. High therapeutic efficacy is achieved through surface functionalization, site-specific targeting, and the use of stimuli-responsive components. In particular, pH and redox dual-stimuli-based polymeric nanocomposites for cancer therapeutics have scarcely been reported. This article provides recent progress in pH- and redox-responsive polymer nanocomposites for site-specific drug delivery in cancer therapy. It explores the design principles, fabrication methods, mechanisms of action, and prospects of these dual-stimuli-responsive biomaterials. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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27 pages, 6818 KiB

Open AccessReview

Progress in Studies of Disentangled Polymers and Composites

by Andrzej Pawlak and Justyna Krajenta

J. Compos. Sci. 2023, 7(12), 521; https://doi.org/10.3390/jcs7120521 - 18 Dec 2023

Cited by 2 | Viewed by 2341

Abstract

Macromolecule entanglements are common in polymers. The first part of this review describes their influence on the properties of entangled polymers. Then, methods for reducing the entanglement density of macromolecule chains are discussed. It has been shown that research on partially disentangled polymers [...] Read more.

Macromolecule entanglements are common in polymers. The first part of this review describes their influence on the properties of entangled polymers. Then, methods for reducing the entanglement density of macromolecule chains are discussed. It has been shown that research on partially disentangled polymers has provided a lot of new information about the relationship between the entangled state and properties of polymers. This research concerns, among others, mechanical and thermal properties and the crystallization process. A special disentangled polymer case, ultra-high-molecular-weight polyethylene, is also discussed. The results of research on polymer composites in which macromolecules were disentangled via processing and composites were produced using already disentangled polymers are presented in particular detail. It has been indicated that such composites and blends of disentangled polymers are promising and will probably be intensively researched in the near future. Full article

(This article belongs to the Special Issue Progress in Polymer Composites, Volume III)

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