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17 pages, 3960 KiB

Open AccessArticle

Effect of Thiophene Insertion on X-Shaped Anthracene-Based Hole-Transporting Materials in Perovskite Solar Cells

by Dharuman Chandrasekaran, Wei-Hao Chiu, Kun-Mu Lee, Jian-Ming Liao, Hsien-Hsin Chou and Yung-Sheng Yen

Polymers 2022, 14(8), 1580; https://doi.org/10.3390/polym14081580 - 13 Apr 2022

Cited by 2 | Viewed by 2561

Abstract

In this work, two novel tetra-substituted X-shaped molecules X1 and X2 that were constructed with anthracene as the central core and arylamine as the donor groups have been synthesized. The HTMs X1 and X2 were synthesized in two steps from industrially accessible [...] Read more.

In this work, two novel tetra-substituted X-shaped molecules X1 and X2 that were constructed with anthracene as the central core and arylamine as the donor groups have been synthesized. The HTMs X1 and X2 were synthesized in two steps from industrially accessible and moderately reasonable beginning reagents. These new HTMs are described in terms of utilization of light absorption, energy level, thermal properties, hole mobility (µ_h), and film-forming property. The photovoltaic performances of these HTMs were effectively assessed in perovskite solar cells (PSCs). The devices based on these HTMs accomplished an overall efficiency of 16.10% for X1 and 10.25% for X2 under standard conditions (AM 1.5 G and 100 mW cm⁻²). This precise investigation provides another perspective on the use of HTMs in PSCs with various device configurations. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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13 pages, 2918 KiB

Open AccessArticle

Characteristic and Synthesis of High-Temperature Resistant Liquid Crystal Epoxy Resin Containing Boron Nitride Composite

by Li-Chuan Wu, Yi-Wen Huang, Yao-Ming Yeh and Chih-Hung Lin

Polymers 2022, 14(6), 1252; https://doi.org/10.3390/polym14061252 - 20 Mar 2022

Cited by 7 | Viewed by 2948

Abstract

Five liquid crystal epoxy resins and composites containing flat boron nitride (f-BN) and spherical boron nitride (s-BN) were successfully synthesized. The chemical structures, crystal diffraction, and thermal conductivity of the liquid crystal (LC) epoxy composites were measured using Nuclear Magnetic Resonance (NMR), Differential [...] Read more.

Five liquid crystal epoxy resins and composites containing flat boron nitride (f-BN) and spherical boron nitride (s-BN) were successfully synthesized. The chemical structures, crystal diffraction, and thermal conductivity of the liquid crystal (LC) epoxy composites were measured using Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC), X-ray, and Discovery Xenon Flash. In this study, the molecular arrangement of five LC epoxy resins and the thermal conductivity of their composites were carefully discussed. Several different amounts of flat boron nitride and spherical boron nitride were added to the five LC epoxy resins. The influence of nano-scale ceramic materials, f-BN, and s-BN, on the thermal conductivity of the LC epoxy resins, was studied. It is worth noting that the thermal conductivity of the spherical boron nitride composite demonstrated a better result than that of the flat boron nitride composite. In simpler terms, the thermal conductivity of the composites is closely related to the molecular arrangement of the LC resin and the amount of BN added. The results demonstrate that the SBPDAE/s-BN (60%) composite shows the highest thermal conductivity of 9.36 W/mK in the vertical direction. These data prove that the LC alignment of the matrix will greatly enhance the thermal conductivity of the composites. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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19 pages, 3361 KiB

Open AccessArticle

Investigation of Calcination of Sepia officinalis Cuttlefish Bone for Reinforcement of Polyvinyl Alcohol Added Nano-Size Montmorillonite

by Jia-Yi Thum, Lee Tin Sin, Soo-Tueen Bee, Jun-Ven Lim and Soo-Ling Bee

Polymers 2022, 14(6), 1089; https://doi.org/10.3390/polym14061089 - 9 Mar 2022

Cited by 4 | Viewed by 2979

Abstract

This study aims to investigate the effects on calcination of Sepia officinalis cuttlefish bone (cuttlebone) to enhance reinforcement of polyvinyl alcohol (PVOH) added with nano-size montmorillonite (MMT) blends as potential bio-compatible materials. The polyvinyl alcohol-cuttlebone-montmorillonite nanocomposites were prepared using the solution casting method. [...] Read more.

This study aims to investigate the effects on calcination of Sepia officinalis cuttlefish bone (cuttlebone) to enhance reinforcement of polyvinyl alcohol (PVOH) added with nano-size montmorillonite (MMT) blends as potential bio-compatible materials. The polyvinyl alcohol-cuttlebone-montmorillonite nanocomposites were prepared using the solution casting method. Calcined cuttlebone particles were added to the PVOH matrix at different amount of 2 and 5 parts per hundred resin (phr) along with MMT ranging from 1 to 3 phr. Results showed that the tensile strength of cuttlebone-added PVOH-MMT composites at fixed 1 phr MMT was observed to be marginally lower when the cuttlebone increased from 2 phr to 5 phr due to the poor distribution of agglomerated particles. Nevertheless, at higher loading level of MMT, it was found that the addition of cuttlebone at 5 phr exhibited a reinforcing effect in PVOH-MMT blends. This is consistent with the scanning electron microscopy observation, where dispersion of a higher amount of cuttlebone in PVOH-MMT blends was observed to be more homogeneous than a lower amount of cuttlebone. Moreover, based on the X-ray diffraction analysis, the addition of cuttlebone significantly enhanced the intercalation effect of MMT particles in the PVOH matrix. Furthermore, the observation from infrared spectroscopy shows the amount of hydroxyl group for all composites reduced gradually with the increasing amount of cuttlebone. The addition of cuttlebone showed a “red shift” effect, indicating the formation of hydrogen bonds induced by cuttlebone. Lastly, lower enthalpy of melting was detected in relation to higher loading level of cuttlebone embedded in PVOH-MMT blends through differential scanning calorimetry. In conclusion, the blending of cuttlebone in PVOH-MMT is favorable to obtain better properties of composites. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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21 pages, 6775 KiB

Open AccessArticle

Characterisation of Hemp Fibres Reinforced Composites Using Thermoplastic Polymers as Matrices

by Lucia Stelea, Ioan Filip, Gabriela Lisa, Mariana Ichim, Mioara Drobotă, Costică Sava and Augustin Mureșan

Polymers 2022, 14(3), 481; https://doi.org/10.3390/polym14030481 - 25 Jan 2022

Cited by 41 | Viewed by 5874

Abstract

Hemp fibres used as a reinforcing agent and three polymeric matrices (polypropylene, bicomponent, recycled polyester) were used to obtain composite materials by needle punching and heat pressing. The influence of the hemp/matrix ratio and the nature of the matrix on the properties of [...] Read more.

Hemp fibres used as a reinforcing agent and three polymeric matrices (polypropylene, bicomponent, recycled polyester) were used to obtain composite materials by needle punching and heat pressing. The influence of the hemp/matrix ratio and the nature of the matrix on the properties of the composites were analysed. The obtained composites were characterised by physical–mechanical indices, thermal analysis (thermogravimetry (TG), differential thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC)), Fourier Transform Infrared Spectroscopy (FTIR-ATR) analysis, Scanning Electron Microscopy (SEM) and Chromatic measurements. The mechanical properties of composites are influenced by both the hemp/matrix ratio and the nature of the matrix. The thermal stability of composites decreased as the amount of hemp increased (for the same mass losses, the decomposition temperature decreased significantly for composites containing a quantity of hemp greater than 50%). Regarding the nature of the matrix, for the same mass loss, the highest decomposition temperature was presented by the composites containing recycled polyester as matrix, and the lowest one was presented by composites containing polypropylene fibres as matrix. The FTIR and SEM analyses highlight the changes that occurred in the structure of the composite, changes determined both by the amount of hemp in the composite and by the nature of the matrix. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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14 pages, 2898 KiB

Open AccessArticle

Development of Cerium Oxide/Corncob Nanocomposite: A Cost-Effective and Eco-Friendly Adsorbent for the Removal of Heavy Metals

by Sidra Gran, Rukhsanda Aziz, Muhammad Tariq Rafiq, Maryam Abbasi, Abdul Qayyum, Ashraf Y. Elnaggar, Hussein H. Elganzory, Zeinhom M. El-Bahy and Enas E. Hussein

Polymers 2021, 13(24), 4464; https://doi.org/10.3390/polym13244464 - 20 Dec 2021

Cited by 12 | Viewed by 3291

Abstract

This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or [...] Read more.

This research aims to assess the efficiency of the synthesized corncob as a cost-effective and eco-friendly adsorbent for the removal of heavy metals. Therefore, to carry out the intended research project, initially, the corncob was doped with nanoparticles to increase its efficiency or adsorption capacity. The prepared adsorbent was evaluated for the adsorption of cadmium (Cd) and chromium (Cr) from aqueous media with the batch experiment method. Factors that affect the adsorption process are pH, initial concentration, contact time and adsorbent dose. The analysis of Cd and Cr was performed by using atomic absorption spectrometry (AAS), while the characterization of the adsorbent was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that there is a significant difference before and after corncob activation and doping with CeO₂ nanoparticles. The maximum removal for both Cd and Cr was at a basic pH with a contact time of 60 min at 120 rpm, which is 95% for Cd and 88% for Cr, respectively. To analyze the experimental data, a pseudo-first-order kinetic model, pseudo-second-order kinetic model, and intra-particle diffusion model were used. The kinetic adsorption studies confirmed that the experimental data were best fitted with the pseudo-second-order kinetic model (R² = 0.989) and intra-particle diffusion model (R² = 0.979). This work demonstrates that the cerium oxide/corncob nanocomposite is an inexpensive and environmentally friendly adsorbent for the removal of Cd and Cr from wastewater. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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18 pages, 4051 KiB

Open AccessArticle

Characteristics of PEO Incorporated with CaTiO₃ Nanoparticles: Structural and Optical Properties

by Shujahadeen B. Aziz, Muaffaq M. Nofal, Mohamad A. Brza, Sarkawt A. Hussein, Khaled H. Mahmoud, Zeinhom M. El-Bahy, Elham M. A. Dannoun, Wrya O. Kareem and Ahang M. Hussein

Polymers 2021, 13(20), 3484; https://doi.org/10.3390/polym13203484 - 11 Oct 2021

Cited by 18 | Viewed by 2660

Abstract

In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO₃) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms [...] Read more.

In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO₃) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms the growth of amorphous nature within PEO with CaTiO₃ addition. The optical band gaps of pure PEO and PEO/CaTiO₃ NC films were calculated using analysis of ultraviolet–visible (UV-Vis) spectra. The change in absorption edge toward lower photon energy is evidence of polymer modification. The dispersion behavior of the refractive index of PEO was manipulated to a higher wavelength upon doping with CaTiO₃. Upon adding CaTiO₃ to the pure PEO polymer, the dielectric constant and refractive index were considerably modified. The band gap shifts from 4.90 eV to 4.19 eV for the PEO incorporated with an optimum portion of 8 wt. % of CaTiO₃. The types of the electronic transition in composite samples were specified, based on the Taucs model and the optical dielectric loss. The alteration of UV/Vis absorption spectra of the NC film was considered a suitable candidate to be applied in nanotechnology-based devices. The spherulites ascribed to the crystalline phase were distinguished through the optical microscopy (OM) study. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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11 pages, 3236 KiB

Open AccessArticle

The Crystallisation, Microphase Separation and Mechanical Properties of the Mixture of Ether-Based TPU with Different Ester-Based TPUs

by Yu-Hui Que, Ying Shi, Li-Zhi Liu, Yuan-Xia Wang, Chen-Chen Wang, Hai-Chao Zhang and Xu-Yang Han

Polymers 2021, 13(20), 3475; https://doi.org/10.3390/polym13203475 - 10 Oct 2021

Cited by 15 | Viewed by 3873

Abstract

The difference in compatibility at the molecular level can lead to a change of microphase separation structure of thermoplastic polyurethanes blend systems, which will improve their thermal and mechanical properties. In this study, TDI-polyester based TPU was blended with MDI-polyether-based TPU and MDI-polyester [...] Read more.

The difference in compatibility at the molecular level can lead to a change of microphase separation structure of thermoplastic polyurethanes blend systems, which will improve their thermal and mechanical properties. In this study, TDI-polyester based TPU was blended with MDI-polyether-based TPU and MDI-polyester based TPU, with different ratios. In the blend system, the obvious reduction of the melting temperature of the high-temperature TDI-polyester based TPU component indicates its hard segments can be mutually integrated with the other component. For TDI-polyester based TPU/MDI-polyether based TPU blends, their similar hard segment ratio and similar chemical structure of the soft segment give the molecular chains of the two components better compatibility. The aggregation structure of the two kinds of chains can rearrange at the molecular level which makes the hard domains mutually integrate to form a new phase separation structure with larger phase region distance. As a result, the yield strength of this blend increased by almost 143% when the elongation at break was only reduced by 12%. In contrast, the other group of blends still partly maintain their respective micro domains, forming a weak interface and leading to a decreased of elongation at break. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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12 pages, 3823 KiB

Open AccessArticle

Carbon Nanotube Reinforced Poly(ε-caprolactone)/Epoxy Blends for Superior Mechanical and Self-Sensing Performance in Multiscale Glass Fiber Composites

by Xoan F. Sánchez-Romate, Andrés Alvarado, Alberto Jiménez-Suárez and Silvia G. Prolongo

Polymers 2021, 13(18), 3159; https://doi.org/10.3390/polym13183159 - 18 Sep 2021

Cited by 5 | Viewed by 2409

Abstract

In this paper, a novel carbon nanotube (CNT) polycaprolactone (PCL), epoxy, and glass fiber (GF) composite is reported. Here, the nanoreinforced composites show a flexural strength increase of around 30%, whereas the interlaminar shear strength increases by 10–15% in comparison to unenhanced samples. [...] Read more.

In this paper, a novel carbon nanotube (CNT) polycaprolactone (PCL), epoxy, and glass fiber (GF) composite is reported. Here, the nanoreinforced composites show a flexural strength increase of around 30%, whereas the interlaminar shear strength increases by 10–15% in comparison to unenhanced samples. This occurs because the addition of the CNTs induces a better PCL/epoxy/GF interaction. Furthermore, the nanoparticles also give novel functionalities to the multiscale composite, such as strain and damage monitoring. Here, the electrical response of the tensile- and compressive-subjected faces was simultaneously measured during flexural tests as well as the transverse conductivity in interlaminar tests, showing an exceptional capability for damage detection. Moreover, it was observed that the electrical sensitivity increases with PCL content due to a higher efficiency of the dispersion process that promotes the creation of a more uniform electrical network. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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12 pages, 3832 KiB

Open AccessArticle

Thermal Stability, Smoke Density, and Flame Retardance of Ecotype Bio-Based Flame Retardant Agricultural Waste Bagasse/Epoxy Composites

by Shang-Hao Liu, Cing-Yu Ke and Chin-Lung Chiang

Polymers 2021, 13(17), 2977; https://doi.org/10.3390/polym13172977 - 2 Sep 2021

Cited by 9 | Viewed by 3167

Abstract

In the study, agricultural waste bagasse was used as a bio-based flame retardant for reducing the flammability of epoxy. Specifically, an interpenetrating network (IPN) was formed through a ring opening reaction between the hydroxyl functional group of bagasse and the epoxy group of [...] Read more.

In the study, agricultural waste bagasse was used as a bio-based flame retardant for reducing the flammability of epoxy. Specifically, an interpenetrating network (IPN) was formed through a ring opening reaction between the hydroxyl functional group of bagasse and the epoxy group of triglycidyl isocyanurate (TGIC), forming Bagasse@TGIC. Next, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) was mixed with Bagasse@TGIC, inducing a reaction between the active hydrogen of DOPO and the epoxy group of TGIC, ultimately forming Bagasse@TGIC@DOPO with an IPN structure. Finally, the novel flame retardant was added to epoxy to create a composite. The integral procedural decomposition temperature (IPDT) of pure epoxy is 619 °C; after the introduction of the 30 wt% flame retardant, the IPDT of the resultant composite material increased to 799 °C, greatly increasing the thermal stability by 29%. After the addition of the Bagasse@TGIC@DOPO flame retardant, the limiting oxygen index increased from 21% for the pure epoxy to 29% for the composite, and the UL-94 rating improved from failing rating for the pure epoxy and V-0 rating for the composite. The Raman spectrum indicated that the addition of Bagasse@TGIC@DOPO IPN substantially increased the biochar yield during the burning process, increasing thermal stability. These results confirmed that the epoxy/Bagasse@TGIC@DOPO composite had substantial flame retarding effects. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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12 pages, 4285 KiB

Open AccessArticle

Enhancement of Gel Strength of Itaconic Acid-Based Superabsorbent Polymer Composites Using Oxidized Starch

by Haechan Kim, Jungsoo Kim and Donghyun Kim

Polymers 2021, 13(17), 2859; https://doi.org/10.3390/polym13172859 - 25 Aug 2021

Cited by 11 | Viewed by 2788

Abstract

Herein, core-superabsorbent polymer (CSAP) composites are prepared from oxidized starch (OS) via aqueous solution copolymerization using ammonium persulfate as the initiator, and 1,6-hexanediol diacrylate as the inner-crosslinker. The surface-crosslinking process is performed using various surface-crosslinkers, including bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) [...] Read more.

Herein, core-superabsorbent polymer (CSAP) composites are prepared from oxidized starch (OS) via aqueous solution copolymerization using ammonium persulfate as the initiator, and 1,6-hexanediol diacrylate as the inner-crosslinker. The surface-crosslinking process is performed using various surface-crosslinkers, including bisphenol A diglycidyl ether (BADGE), poly(ethylene glycol) diglycidyl ether (PEGDGE), ethylene glycol diglycidyl ether (EGDGE), and diglycidyl ether (DGE). The structures of the CSAP composites and their surface-crosslinked SAPs (SSAPs) are characterized using Fourier transform infrared (FT-IR) spectroscopy, their absorption properties are measured via centrifuge retention capacity (CRC), absorbency under load (AUL), permeability, and re-swellability tests, and their gel strengths according to surface-crosslinker type and EGDGE content are examined via rheological analysis. The results indicate that an EGDGE content of 0.75 mol provides the optimum surface-crosslinking and SSAP performance, with a CRC of 34.8 g/g, an AUL of 27.2 g/g, and a permeability of 43 s. The surface-crosslinking of the CSAP composites using OS is shown to improve the gel strength, thus enabling the SAP to be used in disposable diapers. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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11 pages, 3691 KiB

Open AccessArticle

Preparation and Characterization of Eco-Friendly Spent Coffee/ENR50 Biocomposite in Comparison to Carbon Black

by Gunasunderi Raju, Mohammad Khalid, Mahmoud M. Shaban and Baharin Azahari

Polymers 2021, 13(16), 2796; https://doi.org/10.3390/polym13162796 - 20 Aug 2021

Cited by 12 | Viewed by 2631

Abstract

This study investigates the impact of spent coffee biochar (Biochar) compared to carbon black (CB) as a partial replacement for carbon black in epoxidized natural rubber (ENR). Particle size and elemental analysis were used to characterize the biochar and CB. Cure characteristics, tensile, [...] Read more.

This study investigates the impact of spent coffee biochar (Biochar) compared to carbon black (CB) as a partial replacement for carbon black in epoxidized natural rubber (ENR). Particle size and elemental analysis were used to characterize the biochar and CB. Cure characteristics, tensile, thermal, and morphological properties on the effect of biochar and CB as filler were studied. It was found that incorporating 10 phr of spent coffee biochar could improve the composites’ tensile properties and thermal performance compared to carbon black. However, the addition of biochar significantly affects the maximum torque compared to CB and delays the vulcanization time. SEM study shows that biochar has a strong effect on the morphology of composite films. The FTIR graph reveals no substantial difference between compounds with biochar and CB. According to the thermal calorimetric study, the thermal stability of ENR-Biochar is higher than that of ENR-CB. Additionally, these findings suggest that the utilization of spent coffee as a sustainable biochar could be further explored, but little has been done in epoxidized natural rubber (ENR). Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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11 pages, 5037 KiB

Open AccessArticle

Synthesis and Characterization of Conducting PANDB/χ-Al₂O₃ Core-Shell Nanocomposites by In Situ Polymerization

by Cheng-Ho Chen, Ying-Chen Lin and Fu-Su Yen

Polymers 2021, 13(16), 2787; https://doi.org/10.3390/polym13162787 - 19 Aug 2021

Cited by 2 | Viewed by 1891

Abstract

Polyaniline doped with dodecylbenzenesulfonic acid/χ-aluminum oxide (PANDB/χ-Al₂O₃) conducting core-shell nanocomposites was synthesized via an in situ polymerization method in this study. PANDB was synthesized in the presence of dodecylbenzenesulfonic acid (DBSA), which functioned as a dopant and surfactant. The [...] Read more.

Polyaniline doped with dodecylbenzenesulfonic acid/χ-aluminum oxide (PANDB/χ-Al₂O₃) conducting core-shell nanocomposites was synthesized via an in situ polymerization method in this study. PANDB was synthesized in the presence of dodecylbenzenesulfonic acid (DBSA), which functioned as a dopant and surfactant. The electrical conductivity of the conducting PANDB/χ-Al₂O₃ core-shell nanocomposite was approximately 1.7 × 10⁻¹ S/cm when the aniline/χ-Al₂O₃ (AN/χ-Al₂O₃) weight ratio was 1.5. The transmission electron microscopy (TEM) results indicated that the χ-Al₂O₃ nanoflakes were thoroughly coated by PANDB to form the core-shell (χ-Al₂O₃-PANDB) structure. The TEM and field-emission scanning electron microscopy (FE-SEM) images of the conducting PANDB/χ-Al₂O₃ core-shell nanocomposites also indicated that the thickness of the PANDB layer (shell) could be increased as the weight ratio of AN/χ-Al₂O₃ was increased. In this study, the optimum weight ratio of AN/χ-Al₂O₃ was identified as 1.5. The conducting PANDB/χ-Al₂O₃ core-shell nanocomposite was then blended with water-based polyurethane (WPU) to form a conducting WPU/PANDB/χ-Al₂O₃ blend film. The resulting blend film has promising antistatic and electrostatic discharge (ESD) properties. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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28 pages, 6616 KiB

Open AccessArticle

Comparison of Performance Properties and Prediction of Regular and Gamma-Irradiated Granular Waste Polyethylene Terephthalate Modified Asphalt Mixtures

by Aliyu Usman, Muslich Hartadi Sutanto, Madzlan Napiah, Salah E. Zoorob, Nura Shehu Aliyu Yaro and Muhammad Imran Khan

Polymers 2021, 13(16), 2610; https://doi.org/10.3390/polym13162610 - 6 Aug 2021

Cited by 33 | Viewed by 2616

Abstract

The utilization of waste polyethylene terephthalate (WPET) as aggregate substitutes in pavement has been extensively promoted because of its environmental advantages. However, previous studies have shown that a high percentage of WPET reduces the performance of the pavement. To increase the durability of [...] Read more.

The utilization of waste polyethylene terephthalate (WPET) as aggregate substitutes in pavement has been extensively promoted because of its environmental advantages. However, previous studies have shown that a high percentage of WPET reduces the performance of the pavement. To increase the durability of pavement and mitigate the environmental issues caused by WPET, WPET is treated with gamma-irradiation as a component in asphalt mixtures. The study objectives were to investigate the feasibility of using WPET granules as a sustainable aggregate on asphalt mixture stiffness and rutting and predict the asphalt mixture performance containing irradiated WPET via an RSM-ANN-framework. To achieve the objectives, stiffness and rutting tests were conducted to evaluate the WPET modified mixtures’ performance. The result indicated that samples containing 40% irradiated WPET provided a better performance compared to mixtures containing 20% non-irradiated WPET, increasing the stiffness by 27% and 21% at 25 °C and 40 °C, respectively, and rutting resistance by 11% at 45 °C. Furthermore, both predictive models developed demonstrated excellent reliability. The ANN exhibited superior performance than the RSM. The utilization of WPET as aggregate in asphalt mixtures represents a way to addressing related recycling issues while also improving performance. With gamma-irradiation treatment, the utilization of WPET can be increased with improved asphalt mixture performance. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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19 pages, 4126 KiB

Open AccessArticle

Development of Structural Insulated Panels Made from Wood-Composite Boards and Natural Rubber Foam

by Nussalin Thongcharoen, Sureurg Khongtong, Suthon Srivaro, Supanit Wisadsatorn, Tanan Chub-uppakarn and Pannipa Chaowana

Polymers 2021, 13(15), 2497; https://doi.org/10.3390/polym13152497 - 28 Jul 2021

Cited by 8 | Viewed by 5292

Abstract

An experimental study was carried out to develop and examine the properties of a new type of structural insulated panel (SIP). SIP prototypes conducted from this research consisted of insulated foam manufactured from natural rubber filled with wood particles as the core layer [...] Read more.

An experimental study was carried out to develop and examine the properties of a new type of structural insulated panel (SIP). SIP prototypes conducted from this research consisted of insulated foam manufactured from natural rubber filled with wood particles as the core layer and three kinds of commercial wood-composite boards (plywood, cement particleboard, and fiber-cement board) as the surface layers. Polyurethane was used as an adhesive bond between the surface and the core layer. This preformed panel was placed into a clamping device and compressed until adhesive curing was achieved. The physical and mechanical properties of the SIP prototypes were consequently evaluated. The test results indicated that the types of surface layer materials played a significant effect on the SIP properties. The SIP covered with cement particleboard and fiber-cement board revealed high mechanical properties and high water resistance. The SIP prototype covered with plywood showed desirable properties (such as low density, high resistance of screw withdrawal, and low thermal transmittance). However, high water absorption and low fire resistance were drawbacks of the SIP covered with plywood. These properties should be improved. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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15 pages, 3927 KiB

Open AccessArticle

A Study on Circular Economy Material Using Fish Scales as a Natural Flame Retardant and the Properties of Its Composite Materials

by Shang-Hao Liu, Ming-Yuan Shen, Cheng-You Yang and Chin-Lung Chiang

Polymers 2021, 13(15), 2446; https://doi.org/10.3390/polym13152446 - 25 Jul 2021

Cited by 8 | Viewed by 5095

Abstract

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate [...] Read more.

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate (APP), through synergistic effects to reduce the amount of commercial flame retardant. The use of FSs conforms to the concept of a circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt.% (pure EP) to 36.07 wt.%; IPDT from 685.6 °C (pure EP) to 1143.1°C; LOI from 21% (pure EP) to 30%; and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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16 pages, 5495 KiB

Open AccessArticle

Development and Analysis of the Physicochemical and Mechanical Properties of Diorite-Reinforced Epoxy Composites

by Amirbek Bekeshev, Anton Mostovoy, Yulia Kadykova, Marzhan Akhmetova, Lyazzat Tastanova and Marina Lopukhova

Polymers 2021, 13(15), 2421; https://doi.org/10.3390/polym13152421 - 23 Jul 2021

Cited by 23 | Viewed by 2514

Abstract

The aim of this paper is to study the effect of a polyfunctional modifier oligo (resorcinol phenyl phosphate) with terminal phenyl groups and a dispersed mineral filler, diorite, on the physicochemical and deformation-strength properties of epoxy-based composites. The efficiency of using diorite as [...] Read more.

The aim of this paper is to study the effect of a polyfunctional modifier oligo (resorcinol phenyl phosphate) with terminal phenyl groups and a dispersed mineral filler, diorite, on the physicochemical and deformation-strength properties of epoxy-based composites. The efficiency of using diorite as an active filler of an epoxy polymer, ensuring an increase in strength and a change in the physicochemical properties of epoxy composites, has been proven. We selected the optimal content of diorite both as a structuring additive and as a filler in the composition of the epoxy composite (0.1 and 50 parts by mass), at which diorite reinforces the epoxy composite. It has been found that the addition of diorite into the epoxy composite results in an increase in the Vicat heat resistance from 132 to 140–188 °C and increases the thermal stability of the epoxy composite, which is observed in a shift of the initial destruction temperature to higher temperatures. Furthermore, during the thermal destruction of the composite, the yield of carbonized structures increases (from 54 to 70–77% of the mass), preventing the release of volatile pyrolysis products into the gas phase, which leads to a decrease in the flammability of the epoxy composite. The efficiency of the functionalization of the diorite surface with APTES has been proven, which ensures chemical interaction at the polymer matrix/filler interface and also prevents the aggregation of diorite particles, which, in general, provides an increase in the strength characteristics of epoxy-based composite materials by 10–48%. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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18 pages, 5384 KiB

Open AccessArticle

Bacterial Cellulose-Based Nanocomposites Containing Ceria and Their Use in the Process of Stem Cell Proliferation

by Iosif V. Gofman, Alexandra L. Nikolaeva, Albert K. Khripunov, Elena M. Ivan’kova, Anton S. Shabunin, Alexander V. Yakimansky, Dmitriy P. Romanov, Anton L. Popov, Artem M. Ermakov, Sergey O. Solomevich, Pavel M. Bychkovsky, Alexander E. Baranchikov and Vladimir K. Ivanov

Polymers 2021, 13(12), 1999; https://doi.org/10.3390/polym13121999 - 18 Jun 2021

Cited by 16 | Viewed by 3995

Abstract

A technique for the fabrication of bacterial cellulose-based films with CeO₂ nanofiller has been developed. The structural and morphological characteristics of the materials have been studied, their thermal and mechanical properties in dry and swollen states having been determined. The preparation methodology [...] Read more.

A technique for the fabrication of bacterial cellulose-based films with CeO₂ nanofiller has been developed. The structural and morphological characteristics of the materials have been studied, their thermal and mechanical properties in dry and swollen states having been determined. The preparation methodology makes it possible to obtain composites with a uniform distribution of nanoparticles. The catalytic effect of ceria, regarding the thermal oxidative destruction of cellulose, has been confirmed by TGA and DTA methods. An increase in CeO₂ content led to an increase in the elastic modulus (a 1.27-fold increase caused by the introduction of 5 wt.% of the nanofiller into the polymer) and strength of the films. This effect is explained by the formation of additional links between polymer macro-chains via the nanoparticles’ surface. The materials fabricated were characterized by a limited ability to swell in water. Swelling caused a 20- to 30-fold reduction in the stiffness of the material, the mechanical properties of the films in a swollen state remaining germane to their practical use. The application of the composite films in cell engineering as substrates for the stem cells’ proliferation has been studied. The increase in CeO₂ content in the films enhanced the proliferative activity of embryonic mouse stem cells. The cells cultured on the scaffold containing 5 wt.% of ceria demonstrated increased cell survival and migration activity. An analysis of gene expression confirmed improved cultivation conditions on CeO₂-containing scaffolds. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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23 pages, 4467 KiB

Open AccessArticle

Thermo-Mechanical and Delamination Properties in Drilling GFRP Composites by Various Drill Angles

by Usama A. Khashaba, Mohamed S. Abd-Elwahed, Mohamed A. Eltaher, Ismail Najjar, Ammar Melaibari and Khaled I. Ahmed

Polymers 2021, 13(11), 1884; https://doi.org/10.3390/polym13111884 - 6 Jun 2021

Cited by 30 | Viewed by 3701

Abstract

This manuscript aims to study the effects of drilling factors on the thermal-mechanical properties and delamination experimentally during the drilling of glass fiber reinforced polymer (GFRP). Drilling studies were carried out using a CNC machine under dry cutting conditions by 6 mm diameter [...] Read more.

This manuscript aims to study the effects of drilling factors on the thermal-mechanical properties and delamination experimentally during the drilling of glass fiber reinforced polymer (GFRP). Drilling studies were carried out using a CNC machine under dry cutting conditions by 6 mm diameter with different point angles of ∅ = 100°, 118°, and 140°. The drill spindle speed (400, 800, 1600 rpm), feed (0.025, 0.05, 0.1, 0.2 mm/r), and sample thickness (2.6, 5.3, and 7.7 mm) are considered in the analysis. Heat affected zone (HAZ) generated by drilling was measured using a thermal infrared camera and two K-thermocouples installed in the internal coolant holes of the drill. Therefore, two setups were used; the first is with a rotating drill and fixed specimen holder, and the second is with a rotating holder and fixed drill bit. To measure thrust force/torque through drilling, the Kistler dynamometer model 9272 was utilized. Pull-in and push-out delamination were evaluated based on the image analyzed by an AutoCAD technique. The regression models and multivariable regression analysis were developed to find relations between the drilling factors and responses. The results illustrate the significant relations between drilling factors and drilling responses such as thrust force, delamination, and heat affect zone. It was observed that the thrust force is more inspired by feed; however, the speed effect is more trivial and marginal on the thrust force. All machining parameters have a significant effect on the measured temperature, and the largest contribution is of the laminate thickness (33.14%), followed by speed and feed (29.00% and 15.10%, respectively), ended by the lowest contribution of the drill point angle (11.85%). Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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22 pages, 32084 KiB

Open AccessArticle

Native Spider Silk-Based Antimicrobial Hydrogels for Biomedical Applications

by Sinith Withanage, Artemii Savin, Valeria Nikolaeva, Aleksandra Kiseleva, Marina Dukhinova, Pavel Krivoshapkin and Elena Krivoshapkina

Polymers 2021, 13(11), 1796; https://doi.org/10.3390/polym13111796 - 29 May 2021

Cited by 17 | Viewed by 5092

Abstract

Novel antimicrobial natural polymeric hybrid hydrogels based on hyaluronic acid (HA) and spider silk (Ss) were prepared using the chemical crosslinking method. The effects of the component ratios on the hydrogel characteristics were observed parallel to the primary physicochemical characterization of the hydrogels [...] Read more.

Novel antimicrobial natural polymeric hybrid hydrogels based on hyaluronic acid (HA) and spider silk (Ss) were prepared using the chemical crosslinking method. The effects of the component ratios on the hydrogel characteristics were observed parallel to the primary physicochemical characterization of the hydrogels with scanning electron microscopic imaging, Fourier-transform infrared spectroscopy, and contact angle measurements, which confirmed the successful crosslinking, regular porous structure, exact composition, and hydrophilic properties of hyaluronic acid/spider silk-based hydrogels. Further characterizations of the hydrogels were performed with the swelling degree, enzymatic degradability, viscosity, conductivity, and shrinking ability tests. The hyaluronic acid/spider silk-based hydrogels do not show drastic cytotoxicity over human postnatal fibroblasts (HPF). Hydrogels show extraordinary antimicrobial ability on both gram-negative and gram-positive bacteria. These hydrogels could be an excellent alternative that aids in overcoming antimicrobial drug resistance, which is considered to be one of the major global problems in the biomedical industry. Hyaluronic acid/spider silk-based hydrogels are a promising material for collaborated antimicrobial and anti-inflammatory drug delivery systems for external use. The rheological properties of the hydrogels show shear-thinning properties, which suggest that the hydrogels could be applied in 3D printing, such as in the 3D printing of antimicrobial surgical meshes. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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28 pages, 5909 KiB

Open AccessArticle

Synthesis of Poly(methacrylic acid-co-butyl acrylate) Grafted onto Functionalized Carbon Nanotube Nanocomposites for Drug Delivery

by Josué A. Torres-Ávalos, Leonardo R. Cajero-Zul, Milton Vázquez-Lepe, Fernando A. López-Dellamary, Antonio Martínez-Richa, Karla A. Barrera-Rivera, Francisco López-Serrano and Sergio M. Nuño-Donlucas

Polymers 2021, 13(4), 533; https://doi.org/10.3390/polym13040533 - 11 Feb 2021

Cited by 11 | Viewed by 3702

Abstract

Design of a smart drug delivery system is a topic of current interest. Under this perspective, polymer nanocomposites (PNs) of butyl acrylate (BA), methacrylic acid (MAA), and functionalized carbon nanotubes (CNTs_f) were synthesized by in situ emulsion polymerization (IEP). Carbon nanotubes [...] Read more.

Design of a smart drug delivery system is a topic of current interest. Under this perspective, polymer nanocomposites (PNs) of butyl acrylate (BA), methacrylic acid (MAA), and functionalized carbon nanotubes (CNTs_f) were synthesized by in situ emulsion polymerization (IEP). Carbon nanotubes were synthesized by chemical vapor deposition (CVD) and purified with steam. Purified CNTs were analyzed by FE-SEM and HR-TEM. CNTs_f contain acyl chloride groups attached to their surface. Purified and functionalized CNTs were studied by FT-IR and Raman spectroscopies. The synthesized nanocomposites were studied by XPS, ¹³C-NMR, and DSC. Anhydride groups link CNTs_f to MAA–BA polymeric chains. The potentiality of the prepared nanocomposites, and of their pure polymer matrices to deliver hydrocortisone, was evaluated in vitro by UV–VIS spectroscopy. The relationship between the chemical structure of the synthesized nanocomposites, or their pure polymeric matrices, and their ability to release hydrocortisone was studied by FT-IR spectroscopy. The hydrocortisone release profile of some of the studied nanocomposites is driven by a change in the inter-associated to self-associated hydrogen bonds balance. The CNTs_f used to prepare the studied nanocomposites act as hydrocortisone reservoirs. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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16 pages, 5554 KiB

Open AccessArticle

Comparative Studies of CPEs Modified with Distinctive Metal Nanoparticle-Decorated Electroactive Polyimide for the Detection of UA

by Aamna Bibi, Sheng-Chieh Hsu, Wei-Fu Ji, Yi-Chi Cho, Karen S. Santiago and Jui-Ming Yeh

Polymers 2021, 13(2), 252; https://doi.org/10.3390/polym13020252 - 13 Jan 2021

Cited by 8 | Viewed by 2463

Abstract

In this present work, an electrochemical sensor was developed for the sensing of uric acid (UA). The sensor was based on a carbon paste electrode (CPE) modified with electroactive polyimide (EPI) synthesized using aniline tetramer (ACAT) decorated with reduced nanoparticles (NPs) of Au, [...] Read more.

In this present work, an electrochemical sensor was developed for the sensing of uric acid (UA). The sensor was based on a carbon paste electrode (CPE) modified with electroactive polyimide (EPI) synthesized using aniline tetramer (ACAT) decorated with reduced nanoparticles (NPs) of Au, Pt, and Ag. The initial step involved the preparation and characterization of ACAT. Subsequently, the ACAT-based EPI synthesis was performed by chemical imidization of its precursors 4,4′-(4.4′-isopropylidene-diphenoxy) bis (phthalic anhydride) BPADA and ACAT. Then, EPI was doped with distinctive particles of Ag, Pt and Au, and the doped EPIs were abbreviated as EPIS, EPIP and EPIG, respectively. Their structures were characterized by XRD, XPS, and TEM, and the electrochemical properties were determined by cyclic voltammetry and chronoamperometry. Among these evaluated sensors, EPI with Au NPs turned out the best with a sensitivity of 1.53 uA uM⁻¹ UA, a low limit of detection (LOD) of 0.78 uM, and a linear detection range (LDR) of 5–50 uM UA at a low potential value of 310 mV. Additionally, differential pulse voltammetric (DPV) analysis showed that the EPIG sensor showed the best selectivity for a tertiary mixture of UA, dopamine (DA), and ascorbic acid (AA) as compared to EPIP and EPIS. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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20 pages, 5989 KiB

Open AccessArticle

Study on the Effect of Zinc on the Rheological, Mechanical and Thermal Properties and Fire Hazard of Unfilled and Filled CR/BR Vulcanizates

by Aleksandra Smejda-Krzewicka, Anna Słubik, Krzysztof Strzelec and Przemysław Rybiński

Polymers 2020, 12(12), 2904; https://doi.org/10.3390/polym12122904 - 3 Dec 2020

Cited by 4 | Viewed by 1891

Abstract

This paper discusses the cross-linking and functional properties of elastomer composites containing chloroprene rubber (CR) and butadiene rubber (BR) cured in the presence of zinc (Zn) and reinforced with mineral fillers. The research aimed to evaluate the effectiveness of zinc as a new [...] Read more.

This paper discusses the cross-linking and functional properties of elastomer composites containing chloroprene rubber (CR) and butadiene rubber (BR) cured in the presence of zinc (Zn) and reinforced with mineral fillers. The research aimed to evaluate the effectiveness of zinc as a new cross-linking substance with the simultaneous production of elastomer materials with good mechanical properties and a reduced fire hazard. The article concerns the study and explanation of the dependencies influencing the processing and functional properties of unfilled or filled elastomer blends containing different elastomers ratio or different zinc’s amount. The following fillers were used: silica, kaolin, chalk and montmorillonite. The results revealed that the cross-linking degree of CR/BR blends decreased with the increasing amount of butadiene rubber in the blends. The mechanical properties of the cured blends depended on the proportion of elastomers in the composites, the zinc amount, and the presence and type of filler. The flammability of CR/BR/Zn vulcanizates has been investigated before and after the filling. The parameters assessed by the oxygen index method and cone calorimetry, characterizing the behavior of the tested CR/BR/Zn vulcanizates under fire conditions, have shown that they constitute a low fire hazard and can be considered as non-flammable materials. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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30 pages, 5002 KiB

Open AccessReview

Physical, Mechanical and Perforation Resistance of Natural-Synthetic Fiber Interply Laminate Hybrid Composites

by Siti Nadia Mohd Bakhori, Mohamad Zaki Hassan, Noremylia Mohd Bakhori, Khairur Rijal Jamaludin, Faizir Ramlie, Mohd Yusof Md Daud and Sa’ardin Abdul Aziz

Polymers 2022, 14(7), 1322; https://doi.org/10.3390/polym14071322 - 24 Mar 2022

Cited by 24 | Viewed by 5036

Abstract

Natural and synthetic fibres have emerged in high demand due to their excellent properties. Natural fibres have good mechanical properties and are less expensive, making them a viable substitute for synthetic fibers. Owing to certain drawbacks such as their inconsistent quality and hydrophilic [...] Read more.

Natural and synthetic fibres have emerged in high demand due to their excellent properties. Natural fibres have good mechanical properties and are less expensive, making them a viable substitute for synthetic fibers. Owing to certain drawbacks such as their inconsistent quality and hydrophilic nature, researchers focused on incorporating these two fibres as an alternative to improve the limitations of the single fibre. This review focused on the interply hybridisation of natural and synthetic fibres into composites. Natural fibres and their classifications are discussed. The physical and mechanical properties of these hybrid composites have also been included. A full discussion of the mechanical properties of natural/synthetic fibre hybrid composites such as tensile, flexural, impact, and perforation resistance, as well as their failure modes, is highlighted. Furthermore, the applications and future directions of hybrid composites have been described in details. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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12 pages, 1378 KiB

Open AccessReview

How Effective Are Antimicrobial Agents on Preventing the Adhesion of Candida albicans to Denture Base Acrylic Resin Materials? A Systematic Review

by Salwa Omar Bajunaid

Polymers 2022, 14(5), 908; https://doi.org/10.3390/polym14050908 - 24 Feb 2022

Cited by 26 | Viewed by 3918

Abstract

Denture stomatitis is a common oral infection caused by Candid albicans. It occurs under removable dentures due to several causative and contributing factors. If not treated, it can lead to fatal systemic candida infections. Different materials and techniques have been used to treat [...] Read more.

Denture stomatitis is a common oral infection caused by Candid albicans. It occurs under removable dentures due to several causative and contributing factors. If not treated, it can lead to fatal systemic candida infections. Different materials and techniques have been used to treat denture stomatitis; however, no single treatment has succeeded. The purpose of this study was to review novel techniques for incorporating antimicrobial and protein repellent agents into denture acrylic resin materials and their effect on the adhesion of Candida albicans to denture base acrylic resin materials to prevent and/or treat denture stomatitis. A systematic review was conducted in which an electronic search was undertaken using different databases and relevant keywords. The literature search revealed numerous studies describing different antifungal materials incorporated into different denture acrylic resin materials. The investigated materials showed significant antimicrobial activity with slight or no effect on the physical and mechanical properties; however, the optical properties were particularly affected with higher concentrations. The incorporation of antimicrobial agents to reduce or prevent Candida albicans biofilm formation on acrylic resin proved to be very effective, and this effect was found to be proportional to the percentage of the material used. The latter should be considered carefully not to alter the physical, mechanical or optical characteristics of the denture base material. Full article

(This article belongs to the Special Issue Advances in Polymer Composites)

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