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13 pages, 5179 KiB

Open AccessArticle

Development of a Polyethylene Breathable Packaging Film with Modified Microcrystalline Cellulose for Fresh Products

by Pedro V. Rodrigues, M. Cidália R. Castro, Ana M. S. Soares, Liliana Melro and Ana V. Machado

Macromol 2024, 4(2), 269-281; https://doi.org/10.3390/macromol4020015 - 28 Apr 2024

Viewed by 1035

Abstract

In this study, a material based on polyethylene (PE) and microcrystalline cellulose (MC) was developed as a breathable packaging film. Surface functionalization of MC with 3-aminopropyltriethoxysilane (APTES) has been shown to be an efficient option to tailor their properties and increase opportunities for [...] Read more.

In this study, a material based on polyethylene (PE) and microcrystalline cellulose (MC) was developed as a breathable packaging film. Surface functionalization of MC with 3-aminopropyltriethoxysilane (APTES) has been shown to be an efficient option to tailor their properties and increase opportunities for the application of MC on the reinforcement of polymers such as polyethylene (PE). The functionalization of MC with the mentioned silane derivative was achieved using a green method and later used in the development of composites with PE in three percentages (1, 3, and 5%). All the materials were prepared by melt blending and characterized in terms of structural properties (ATR-FTIR and FTIR in transmittance mode, EDX, and SEM), thermal properties (DSC and TGA), thermomechanical properties (DMA), contact angle measurements and permeability to water vapor. The materials demonstrated the potential to be used as breathable film packaging for fresh products. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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18 pages, 3407 KiB

Open AccessArticle

Kinetic, Isothermal, and Thermodynamic Analyses of Adsorption of Humic Acid on Quaternized Porous Cellulose Beads

by Kana Uchiyama, Hiromichi Asamoto, Hiroaki Minamisawa and Kazunori Yamada

Macromol 2024, 4(1), 117-134; https://doi.org/10.3390/macromol4010006 - 5 Mar 2024

Viewed by 843

Abstract

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC), and the potential use of the quaternized cellulose beads as an adsorbent was explored for the removal of humic acid (HA) from aqueous media. The introduction of quaternary ammonium groups was verified by FT-IR [...] Read more.

Porous cellulose beads were quaternized with glycidyltrimethylammonium chloride (GTMAC), and the potential use of the quaternized cellulose beads as an adsorbent was explored for the removal of humic acid (HA) from aqueous media. The introduction of quaternary ammonium groups was verified by FT-IR and XPS analyses, and their content increased to 0.524 mmol/g-Qcell by increasing the GTMAC concentration. The adsorption capacity of the HA increased with decreasing initial pH value and/or increasing content of quaternary ammonium groups, and a maximum adsorption capacity of 575 mg/g-Qcell was obtained for the quaternized cellulose beads with a content of quaternary ammonium groups of 0.380 mmol/g-Qcell. The removal % value increased with increasing dose of quaternized cellulose beads, and HA was highly removed at higher quaternary ammonium groups. The kinetics of the HA adsorption in this study followed a pseudo-second-order equation, and the process exhibited a better fit to the Langmuir isotherm. In addition, the k₂ value increased with increasing temperature. These results emphasize that HA adsorption is limited by chemical sorption or chemisorption. The quaternized cellulose beads were repetitively used for the adsorption of HA without appreciable loss in the adsorption capacity. The empirical, equilibrium, and kinetic aspects obtained in this study support that the quaternized cellulose beads can be applied to the removal of HA. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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15 pages, 3907 KiB

Open AccessArticle

Development of Water-Resistant Autohesive Strength of Polyethylene Plates with Photografting of Alkyl (Meth)Acrylates

by Kazunori Yamada, Yuki Kazama and Yuji Kimura

Macromol 2023, 3(3), 554-568; https://doi.org/10.3390/macromol3030032 - 15 Aug 2023

Viewed by 1064

Abstract

This study aims to confer autohesive strength to polyethylene (PE) plates by swelling the grafted layers, which were formed on the PE plates grafted with alkyl (meth)acrylate monomers, with 1,4-dioxane, and subsequently heat-pressing them. For the methyl methacrylate (MMA)-grafted PE (PE-g-PMMA) plates, the [...] Read more.

This study aims to confer autohesive strength to polyethylene (PE) plates by swelling the grafted layers, which were formed on the PE plates grafted with alkyl (meth)acrylate monomers, with 1,4-dioxane, and subsequently heat-pressing them. For the methyl methacrylate (MMA)-grafted PE (PE-g-PMMA) plates, the location of grafting was restricted to the outer surface region and the grafted layer with higher densities of grafted PMMA chains was composed. When the grafted PE plates were immersed in 1,4-dioxane, and then heat-pressed while applying the load, autohesion was developed. The substrate failure was observed for the PE-g-PMMA plates and the grafted amount at which the substrate failure was observed decreased with the procedures that decreased the methanol concentration of the solvent, the MMA concentration, the grafting temperature, and the heat-press temperature, and/or increased the load. The lowest grafted amount of 45 μmol/cm² for the substrate failure was obtained under the conditions where the PE-g-PMMA plate prepared at 0.75 M and 60 °C in a 70 vol% aqueous methanol solution was heat-pressed at 60 °C while applying the load of 2.0 kg/cm². The swelling of the grafted layers with 1,4-dioxane considerably contributed to the development of autohesion, bringing the inter-diffusion of grafted PMMA chains and coincident entanglement of grafted PMMA chains during the heat-pressing. The fact that the substrate failure occurred indicates that an autohesive strength higher than the ultimate strength of the used PE plate was obtained. Our approach provides a novel procedure to develop the water-resistant autohesion of PE plates. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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13 pages, 10962 KiB

Open AccessArticle

The Interplay of Processing-Related Influences on the Formation of Volume Holographic Gratings in a Free-Surface Epoxy-Based Recording Material

by Tina Sabel-Grau

Macromol 2023, 3(2), 211-223; https://doi.org/10.3390/macromol3020013 - 9 May 2023

Viewed by 1125

Abstract

Understanding the formation processes of holographic gratings in polymers as a function of material composition and processing is important for the development of new materials for holography and its associated applications. Among the processing-related factors that affect grating formation in volume holographic recording [...] Read more.

Understanding the formation processes of holographic gratings in polymers as a function of material composition and processing is important for the development of new materials for holography and its associated applications. Among the processing-related factors that affect grating formation in volume holographic recording material, pre-exposure, prebaking and dark storage, as well as the associated variations in layer thickness and composition, are usually underestimated. This study highlights the influence and interaction of these factors and shows that they should not be neglected. This is of particular importance for samples with a free surface. Here, one such epoxy-based free-surface material is investigated. To determine the influence of prebaking on the holographic grating formation, as well as on the achieved refractive index contrast, angular resolved analysis of volume holographic phase gratings is applied through point-by-point scanning of the local material response. Grating characteristics are determined by comparison with simulations based on rigorous coupled wave theory. Thus, the optimal dose for prebaking can be determined, as well as the optimal exposure time, depending on the dose. The influence of dark storage on the material response is investigated over a period of 12 weeks and shows a strong dependence on the deposited energy density. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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18 pages, 2953 KiB

Open AccessArticle

Influence of Concentration of Thiol-Substituted Poly(dimethylsiloxane)s on the Properties, Phases, and Swelling Behaviors of Their Crosslinked Disulfides

by Danielle M. Beaupre, Alexander K. Goroncy and Richard G. Weiss

Macromol 2023, 3(1), 36-53; https://doi.org/10.3390/macromol3010004 - 28 Jan 2023

Cited by 1 | Viewed by 2929

Abstract

A simple, efficient procedure has been employed to effect intra- and inter-chain crosslinking of two commercially available thiolated poly(dimethylsiloxane) copolymers (T-PDMS) with 4–6% or 13–17% of mercaptopropyl side-chains. The thiol functional groups were converted to disulfides (D-PDMS) in chloroform solutions of I₂ [...] Read more.

A simple, efficient procedure has been employed to effect intra- and inter-chain crosslinking of two commercially available thiolated poly(dimethylsiloxane) copolymers (T-PDMS) with 4–6% or 13–17% of mercaptopropyl side-chains. The thiol functional groups were converted to disulfides (D-PDMS) in chloroform solutions of I₂. Importantly, the conditions employed avoid over-oxidation to other types of sulfur-containing species, and the concentration of T-PDMS during the crosslinking reaction dictated the rheological properties and liquid or solid nature of the D-PDMS. The procedure for obtaining the crosslinked copolymers is simpler than other approaches in the literature used to crosslink polysiloxane backbones and to modulate their properties. By changing the concentration of T-PDMS during the treatment with I₂, the degree of intra- and inter-chain crosslinking can be controlled (as assessed qualitatively by the solid or liquid nature of the products and their viscoelastic properties). For each of the T-PDMS materials, there is a concentration threshold, above which products are solids, and below which they are oils. Liquid and solid materials were characterized using ¹H and ¹³C solution-state and ¹³C solid-state NMR spectroscopy, respectively. They indicate greater than 90% conversion of thiols to disulfides in the presence of excess I₂. The rheological behavior of the liquid products, solvent swelling ability of solid products, and the thermal stability of the reactants and products are described. Furthermore, the solid products exhibit some of the highest swelling values reported in the literature for poly(dimethylsiloxane) (PDMS) materials. As assessed by thermal gravimetric analyses, the disulfide-crosslinked materials are more stable thermally than the corresponding thiols. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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8 pages, 3936 KiB

Open AccessArticle

Novel Method of Carbon Precursor Masking to Generate Controlled Perforations in a Carbon Film

by Rami Rouhana, Markus Stommel, Michael Stanko and Markus Muth

Macromol 2022, 2(4), 554-561; https://doi.org/10.3390/macromol2040036 - 5 Dec 2022

Cited by 3 | Viewed by 1875

Abstract

A patterned carbon film was produced from Linear Low-Density Polyethylene (LLDPE) by the implementation of a novel method named Chemical Masking Perforation (CMP). The following paper describes this procedure, starting with the sulfonation of the precursor polymer LLDPE with Chlorosulphonic acid to stabilize [...] Read more.

A patterned carbon film was produced from Linear Low-Density Polyethylene (LLDPE) by the implementation of a novel method named Chemical Masking Perforation (CMP). The following paper describes this procedure, starting with the sulfonation of the precursor polymer LLDPE with Chlorosulphonic acid to stabilize the material, followed by Fourier-transform infrared spectroscopy (FTIR) evaluation to compare the atomic bonds from the stabilized film as well as from the masked sections of the film. To finalize, the cross-linked film was carbonized in an oven at 950 °C. The outcome of this process was a carbon film with a thickness similar to a carbon fiber diameter of 8 µm with controllable size and distribution. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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11 pages, 20566 KiB

Open AccessArticle

Fabrication and Characterization of Free-Standing and Flexible Polyaniline Membranes: Role of Graphene Nanoscrolls

by Rauf Mahmudzade and Dilip Depan

Macromol 2022, 2(4), 543-553; https://doi.org/10.3390/macromol2040035 - 21 Nov 2022

Cited by 4 | Viewed by 1782

Abstract

Wearable technologies can contribute to the early and accurate detection of chronic diseases which can be achieved by the integration of biosensors into wearable technologies. However, the challenges associated with the performance of current electrode materials—i.e., flexibility, conductivity, and mechanical stability, made from [...] Read more.

Wearable technologies can contribute to the early and accurate detection of chronic diseases which can be achieved by the integration of biosensors into wearable technologies. However, the challenges associated with the performance of current electrode materials—i.e., flexibility, conductivity, and mechanical stability, made from conducting polymers are preventing their widespread usage. Herein, we report a freestanding and flexible electrode synthesized from polyaniline (PANI) and graphene nanoscrolls (GNS). The PANI-GNS nanohybrid membranes were synthesized via chemical oxidative polymerization and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nanoindentation (NI), and four-point probe techniques. FTIR results showed an increase in conjugation length of the PANI after the addition of GNS into the mixture which can be indicative of an enhancement of electrical properties. Nanoindentation studies showed an elastic modulus and hardness of 2.6 GPa and 0.17 GPa, respectively, for PANI-GNS-5 nanocomposite, compared to 1.9 GPa and 0.08 GPa, for pure PANI. This was later confirmed by the four-point probe technique as the addition of GNS increased the conductivity of electrodes up to 9 S/cm at a 5% weight ratio. Moreover, SEM results of the PANI-GNS showed an open porous morphology of the polymer matrix in comparison with pure PANI samples which would readily translate into higher amounts of enzyme immobilization on the surface. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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12 pages, 3189 KiB

Open AccessArticle

Characterization of a Biocomposite of Electrospun PVDF Membranes with Embedded BaTiO₃ Micro- and Nanoparticles

by Sérgio D. Almeida, Jorge C. Silva, João P. M. R. Borges and M. Carmo Lança

Macromol 2022, 2(4), 531-542; https://doi.org/10.3390/macromol2040034 - 17 Nov 2022

Cited by 3 | Viewed by 1836

Abstract

Damage to bone tissue is a common health issue that tends to increase in severity with age and other underlying conditions. To take advantage of the piezoelectric effect on bone remodulation, piezoelectric materials can be used to fill patients bone defects. Polyvinylidene fluoride [...] Read more.

Damage to bone tissue is a common health issue that tends to increase in severity with age and other underlying conditions. To take advantage of the piezoelectric effect on bone remodulation, piezoelectric materials can be used to fill patients bone defects. Polyvinylidene fluoride (PVDF) and barium titanate (BaTiO₃) are both well-known polymeric and ceramic biomaterials, respectively, as well as piezoelectric at room temperature. To mimic the extracellular matrix, PVDF membranes were produced by electrospinning onto a rotating drum to promote the alignment of fibers and micro- and nano-sized tetragonal BaTiO₃ particles were embedded into these membranes to try to enhance the piezoelectric response and, therefore, bioactivity. After defining the best deposition parameters to produce pure PVDF membranes, the same parameters were carried over for the embedded membranes and both were characterized, revealing that the proposed method for obtaining β-phase PVDF (the polymer phase with highest piezoelectric coefficient) through electrospinning is viable, producing fibers with coherent diameters and alignment. The presence of barium titanate conferred bioactivity to the membranes and caused a decrease in fibers’ diameter and in superficial charge density. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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11 pages, 2703 KiB

Open AccessArticle

Influence of Surface Texture on Sealing Performance of PTFE Materials

by Xiaosong Ding, Jian Wu, Yonggang Wang, Bo Cui, Shuang An, Benlong Su and Youshan Wang

Macromol 2022, 2(2), 225-235; https://doi.org/10.3390/macromol2020015 - 8 Jun 2022

Cited by 5 | Viewed by 1999

Abstract

Due to the hydrodynamic pressure effect, the bearing capacity of the oil film on the surface of a textured friction pair is greater than that of a smooth surface. In this paper, the effects of PTFE surface texture parameters (shape, depth, width, and [...] Read more.

Due to the hydrodynamic pressure effect, the bearing capacity of the oil film on the surface of a textured friction pair is greater than that of a smooth surface. In this paper, the effects of PTFE surface texture parameters (shape, depth, width, and area ratio) on the oil film bearing capacity and leakage of the sealing system under lubrication are studied using the FLURNT simulation. It is found in this present study that greater texture depths do not necessarily lead to better sealing performance. When the texture depth exceeds a certain level, a reverse flow occurs at the bottom of the texture, thereby weakening the hydrodynamic pressure effect. An optimal texture depth of 5–10 μm maximizes the oil film bearing capacity. Within a certain range, the oil film bearing capacity increases along with texture widths. In addition, leakage of the rectangular texture rises significantly with growing texture widths. Larger texture area ratios result in higher leakage, but the bearing capacity first rises and then falls with an increase in the area ratio, with a maximum value of 70–80%. Considering the influence of texture parameters on oil film bearing capacity and leakage, selecting the most appropriate texture parameters for surface texture treatment optimizes the performance of the sealing system. The findings of this paper provide a theoretical basis for improving the sealing performance of high-end aviation equipment using texture treatment, thereby enabling the application of surface texture technology to improve the tribological properties of materials. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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Review

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17 pages, 1095 KiB

Open AccessReview

Polyphenol-Loaded Polymeric Matrixes as Potential Biopharmaceuticals against Cancer

by Manuel Adrian Picos-Salas, Melissa García-Carrasco, José Basilio Heredia, Luis Angel Cabanillas-Bojórquez, Nayely Leyva-López and Erick Paul Gutiérrez-Grijalva

Macromol 2023, 3(3), 507-523; https://doi.org/10.3390/macromol3030030 - 3 Aug 2023

Cited by 1 | Viewed by 1671

Abstract

Polyphenols have attracted attention for their anti-inflammatory, antidiabetic, and anticancer properties. Due to the antioxidant and anti-inflammatory potential of these molecules, they are also proposed as a potential therapeutic tool to prevent complications of cancer and decrease the secondary effects of conventional chemotherapeutic [...] Read more.

Polyphenols have attracted attention for their anti-inflammatory, antidiabetic, and anticancer properties. Due to the antioxidant and anti-inflammatory potential of these molecules, they are also proposed as a potential therapeutic tool to prevent complications of cancer and decrease the secondary effects of conventional chemotherapeutic drugs. Nonetheless, polyphenols such as flavonoids and phenolic acids have low bioavailability, as they are highly metabolized. Thus, administration strategies have been developed to enhance the anticancer properties of polyphenols. Most of these strategies involve different encapsulation techniques, such as nanoencapsulation, nanoemulsion, and the use of other polymeric matrixes. These techniques can increase the activity of these compounds after going through the gastrointestinal process and improve their solubility in an aqueous medium. This review comprises recent studies regarding encapsulation techniques to enhance the bioactivity of polyphenols against cancer and their current state in clinical studies. Overall, micro- and nanoencapsulation techniques with different polymers enhanced the anticancer properties of polyphenols by inhibiting tumor growth, modulating the expression of genes related to metastasis and angiogenesis, decreasing the expression of pro-inflammatory biomarkers. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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15 pages, 1080 KiB

Open AccessReview

Agar-Agar and Chitosan as Precursors in the Synthesis of Functional Film for Foods: A Review

by Camila Ramão Contessa, Gabriela Silveira da Rosa, Caroline Costa Moraes and Janaina Fernandes de Medeiros Burkert

Macromol 2023, 3(2), 275-289; https://doi.org/10.3390/macromol3020017 - 17 May 2023

Cited by 1 | Viewed by 2886

Abstract

The food industry produces an exorbitant amount of solid waste of petrochemical origin as a result of the increase in the development of new products. Natural polymers are an alternative to this theme; however, their development with adequate properties is a challenge. The [...] Read more.

The food industry produces an exorbitant amount of solid waste of petrochemical origin as a result of the increase in the development of new products. Natural polymers are an alternative to this theme; however, their development with adequate properties is a challenge. The union of different polymers in the synthesis of packaging is usually carried out to improve these properties. The combination of agar-agar and chitosan biopolymers show particular advantages through hydrogen bonds and electrostatic attraction between oppositely charged groups, presenting a promising source of studies for the synthesis of green packaging. When combined with natural extracts with active properties, these polymers allow an increase in the microbiological stability of foods associated with lower chemical preservative content and greater environmental sustainability. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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17 pages, 6085 KiB

Open AccessReview

Composites of Vegetable Oil-Based Polymers and Carbon Nanomaterials

by Ana M. Díez-Pascual and Abbas Rahdar

Macromol 2021, 1(4), 276-292; https://doi.org/10.3390/macromol1040019 - 1 Dec 2021

Cited by 18 | Viewed by 4239

Abstract

Owed to current environmental concerns and crude oil price fluctuations, the design of feasible substitutes to petroleum-based polymeric materials is a major challenge. A lot of effort has been focused on transforming natural vegetable oils (VOs), which are inexpensive, abundant, and sustainable, into [...] Read more.

Owed to current environmental concerns and crude oil price fluctuations, the design of feasible substitutes to petroleum-based polymeric materials is a major challenge. A lot of effort has been focused on transforming natural vegetable oils (VOs), which are inexpensive, abundant, and sustainable, into polymeric materials. Different nanofillers have been combined with these bio-based polymer matrices to improve their thermal, mechanical, and antibacterial properties. The development of multifunctional nanocomposites materials facilitates their application in novel areas such as sensors, medical devices, coatings, paints, adhesives, food packaging, and other industrial appliances. In this work, a brief description of current literature on polymeric nanocomposites from vegetable oils reinforced with carbon nanomaterials is provided, in terms of preparation, and properties. Different strategies to improve the nanomaterial state of dispersion within the biopolymer matrix are discussed, and a correlation between structure and properties is given. In particular, the mechanical, thermal, and electrical properties of these natural polymers can be considerably enhanced through the addition of small quantities of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), graphene (G), or its derivatives such as graphene oxide (GO) or fullerenes (C60). Finally, some current and potential future applications of these materials in diverse fields are briefly discussed. Full article

(This article belongs to the Special Issue Functionalization of Polymers for Advanced Applications)

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