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Polymers
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Sustainable Polymer Composites from Renewable Resources: Functionality and Applications
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Sustainable Polymer Composites from Renewable Resources: Functionality and Applications

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Circular and Green Polymer Science".

Deadline for manuscript submissions: closed (31 March 2024) | Viewed by 36136

Special Issue Editors

Dr. Bo Wang

E-Mail Website
Guest Editor
School of Chemical and Biological Technology, Taiyuan University of Science and Technology, Taiyuan, China
Interests: bio-based polymers and chemicals; polymer engineering; polymer functional modification; polymer composites; cellulose engineering; polymer chemistry and physics; mechanical properties; thermal properties; crystallization behavior; modification of waste plastics
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Jie Li

E-Mail Website
Guest Editor
Department of Polymer Materials and Engineering, School of Materials Science and Engineering, North University of China, Taiyuan, China
Interests: photoelectric functional polymer materials and their flexible devices; preparation and interface research of organic/inorganic photoelectric functional materials; preparation and performance regulation of photosensitive layer materials for novel hybrid solar cells
Prof. Dr. Yingchun Li

E-Mail Website
Guest Editor
Department of Polymer Materials and Engineering, School of Materials Science and Engineering, North University of China, Taiyuan, China
Interests: high-value recycling of waste plastics for electronic appliances; engineering plasticization of polyester bottle flakes; flotation of difficult-to-separate waste plastics; halogen-free flame retardant nylon materials; synthesis and modification of long carbon chain engineering plastics

Special Issue Information

Dear Colleagues,

In recent decades, the production and application of polymers and their composites have increased exponentially. However, the consumption of nonrenewable resources, the disposal of waste polymers and related issues, as well as government policies have led to growing interest in sustainable polymer composites prepared from renewable resources.

At present, sustainable polymers and their composites prepared from renewable resources mainly include polymers and their composites based on biodegradable plastics (PLA, PHBV, PBAT, PHB, PHA, etc.); polymers and their composites based on bio-based polymers (cellulose, chitosan, protein, etc.); modified polymer composites filled with agricultural and forestry wastes; the modification and regeneration of waste plastics.

The aim of this Special Issue is to highlight the progress in the preparation, characterization, properties and applications of polymers, blends and composites prepared from renewable resources.

Dr. Bo Wang
Prof. Dr. Jie Li
Prof. Dr. Yingchun Li
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • bio-based polymers
  • biodegradable polymers
  • sustainable polymer composites
  • sustainable materials
  • renewable resources
  • modification and regeneration of waste plastics

Published Papers (15 papers)

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Research

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20 pages, 9089 KiB  
Article
Chitosan-Based Films Blended with Tannic Acid and Moringa Oleifera for Application in Food Packaging: The Preservation of Strawberries (Fragaria ananassa)
by Raja Venkatesan, Alexandre A. Vetcher, Bandar Ali Al-Asbahi and Seong-Cheol Kim
Polymers 2024, 16(7), 937; https://doi.org/10.3390/polym16070937 - 29 Mar 2024
Viewed by 573
Abstract
Biobased plastics provide a sustainable alternative to conventional food packaging materials, thereby reducing the environmental impact. The present study investigated the effectiveness of chitosan with varying levels of Moringa oleifera seed powder (MOSP) and tannic acid (TA). Chitosan (CS) biocomposite films with tannic [...] Read more.
Biobased plastics provide a sustainable alternative to conventional food packaging materials, thereby reducing the environmental impact. The present study investigated the effectiveness of chitosan with varying levels of Moringa oleifera seed powder (MOSP) and tannic acid (TA). Chitosan (CS) biocomposite films with tannic acid acted as a cross-linker, and Moringa oleifera seed powder served as reinforcement. To enhance food packaging and film performance, Moringa oleifera seed powder was introduced at various loadings of 1.0, 3.0, 5.0, and 10.0 wt.%. Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy analyses were performed to study the structure and morphology of the CS/TA/MOSP films. The scanning electron microscopy results confirmed that chitosan/TA with 10.0 wt.% of MOSP produced a lightly miscible droplet/matrix structure. Furthermore, mechanical properties, swelling, water solubility, optical barrier, and water contact angle properties of the film were also calculated. With increasing Moringa oleifera seed powder contents, the biocomposite films’ antimicrobial and antifungal activity increased at the 10.0 wt.% MOSP level; all of the observed bacteria [Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Aspergillus niger (A. niger), and Candida albicans (C. albicans)] had a notably increased percentage of growth. The film, with 10.0 wt.% MOSP content, effectively preserves strawberries’ freshness, making it an ideal food packaging material. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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13 pages, 6594 KiB  
Article
Maltodextrin-Based Cross-Linked Electrospun Mats as Sustainable Sorbents for the Removal of Atenolol from Water
by Claudio Cecone, Valentina Fiume, Pierangiola Bracco and Marco Zanetti
Polymers 2024, 16(6), 752; https://doi.org/10.3390/polym16060752 - 09 Mar 2024
Viewed by 1049
Abstract
Maltodextrins are products of starch hydrolysis that can be processed into dry fibres through electrospinning and subsequently cured via mild thermal treatment to obtain nonwoven cross-linked polysaccharide-based mats. The sustainability of the process and the bioderived nature make this class of materials suitable [...] Read more.
Maltodextrins are products of starch hydrolysis that can be processed into dry fibres through electrospinning and subsequently cured via mild thermal treatment to obtain nonwoven cross-linked polysaccharide-based mats. The sustainability of the process and the bioderived nature make this class of materials suitable candidates to be studied as renewable sorbents for the removal of contaminants from water. In this work, electrospinning of water solutions containing 50% wt. of commercial maltodextrin (Glucidex 2®) and 16.6% wt. of citric acid was carried out at 1.2 mL/h flow and 30 kV applied voltage, followed by thermal curing at 180 °C of the dry fibres produced to obtain cross-linked mats. Well-defined fibres with a mean diameter of 1.64 ± 0.35 µm were successfully obtained and characterised by scanning electron microscopy, thermogravimetric analysis, and attenuated total reflectance Fourier transform infrared spectroscopy. Afterwards, a series of sorption tests were conducted to evaluate the effectiveness of the mats in removing atenolol from water. The results of the batch tests followed by HPLC-UV/Vis showed high sorption rates, with over 90% of the atenolol removed, and a maximum removal capacity of 7 mg/g. Furthermore, continuous fixed-bed sorption tests proved the positive interaction between the polymers and atenolol. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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17 pages, 3228 KiB  
Article
Synthesis of Poly-Lactic Acid by Ring Open Polymerization from Beer Spent Grain for Drug Delivery
by Snehal R. Vakati, Gary Vanderlaan, Matthew D. Gacura, Xiaoxu Ji, Longyan Chen and Davide Piovesan
Polymers 2024, 16(4), 483; https://doi.org/10.3390/polym16040483 - 08 Feb 2024
Viewed by 1168
Abstract
Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, its drawbacks include weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The [...] Read more.
Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, its drawbacks include weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The development of synthetic polymers that can release antibiotics and other medicines remains a top research priority. This study proposes a novel approach to produce PLA by converting Brewer’s spent grain (BSG) into lactic acid by bacterial fermentation followed by lactide ring polymerization with a metal catalyst. The elution properties of the PLA polymer are evaluated using modified Kirby–Bauer assays involving the antimicrobial chemotherapeutical, trimethoprim (TMP). Molded PLA polymer disks are impregnated with a known killing concentration of TMP, and the PLA is evaluated as a drug vehicle against TMP-sensitive Escherichia coli. This approach provides a practical means of assessing the polymer’s ability to release antimicrobials, which could be beneficial in exploring new drug-eluting synthetic polymer strategies. Overall, this study highlights the potential of using BSG waste materials to produce valuable biomaterials of medical value with the promise of expanded versatility of synthetic PLA polymers in the field of drug-impregnated tissue grafts. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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16 pages, 13214 KiB  
Article
Rice Husk with PLA: 3D Filament Making and Additive Manufacturing of Samples for Potential Structural Applications
by Gabriela Barreto, Santiago Restrepo, Carlos Mauricio Vieira, Sergio Neves Monteiro and Henry A. Colorado
Polymers 2024, 16(2), 245; https://doi.org/10.3390/polym16020245 - 15 Jan 2024
Viewed by 970
Abstract
Additive manufacturing has garnered significant attention as a versatile method for fabricating green and complex composite materials. This study delves into the fabrication of polymer composites by employing polylactic acid (PLA) in conjunction with rice husk as a reinforcing filler. The filaments were [...] Read more.
Additive manufacturing has garnered significant attention as a versatile method for fabricating green and complex composite materials. This study delves into the fabrication of polymer composites by employing polylactic acid (PLA) in conjunction with rice husk as a reinforcing filler. The filaments were made by an extruded filament maker and then were used to make tensile and impact samples by another extrusion technology, fused deposition modeling (FDM). The structural and morphological characteristics of the composite materials were analyzed using scanning electron microscopy SEM. Results show that both the filament and samples are very reliable in producing polymer parts with this rice husk solid waste. This research contributes to increasing materials’ circularity and potentially creating a local social economy around rice production, where this waste is not much used. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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17 pages, 3624 KiB  
Article
Study of the Viscoelastic and Rheological Properties of Rubber-Bitumen Binders Obtained from Rubber Waste
by Anar Akkenzheyeva, Viktors Haritonovs, Akkenzhe Bussurmanova, Remo Merijs-Meri, Yerzhan Imanbayev, Arturs Riekstins, Akmaral Serikbayeva, Serik Sydykov, Murshida Aimova and Gulnara Mustapayeva
Polymers 2024, 16(1), 114; https://doi.org/10.3390/polym16010114 - 29 Dec 2023
Cited by 1 | Viewed by 703
Abstract
According to scientific research from different countries, crumb rubber obtained from end-of-life tires (ELT) during processing can improve the properties of the asphalt mixture, thereby extending the service life of the road surface. This paper presents the modification of bitumen with industrial rubber [...] Read more.
According to scientific research from different countries, crumb rubber obtained from end-of-life tires (ELT) during processing can improve the properties of the asphalt mixture, thereby extending the service life of the road surface. This paper presents the modification of bitumen with industrial rubber waste. The modification of bitumen for roads is considered one of the most suitable and popular approaches. This research paper describes the details of using different types of crumb rubber as bitumen modifiers. The modified bitumen’s main physical and mechanical characteristics were determined after conventional tests: penetration and ductility, softening point, and Fraas brittleness point. In order to obtain a rubber–asphalt concrete mixture with improved performance characteristics, the viscoelastic and rheological properties of rubber–bitumen binders and their comparison with polymer–bitumen binders were also studied. The research results show that with increasing temperature, the values of viscosity, shear stress and complex shear modulus of all studied bitumen systems decrease, the values of the phase shift angle increase, and the size of the rubber particles has a greater influence on the properties of bitumen systems. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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12 pages, 2581 KiB  
Article
Ecotoxicity of Caffeine as a Bio-Protective Component of Flax-Fiber-Reinforced Epoxy-Composite Building Material
by Klára Kobetičová, Jana Nábělková, Viktor Brejcha, Martin Böhm, Miloš Jerman, Jiří Brich and Robert Černý
Polymers 2023, 15(19), 3901; https://doi.org/10.3390/polym15193901 - 27 Sep 2023
Viewed by 663
Abstract
Caffeine is a verified bio-protective substance in the fight against the biodegradation of cellulose materials, but its ecotoxicity in this context has not yet been studied. For this reason, the ecotoxicity of flax-fiber-reinforced epoxy composite with or without caffeine was tested in the [...] Read more.
Caffeine is a verified bio-protective substance in the fight against the biodegradation of cellulose materials, but its ecotoxicity in this context has not yet been studied. For this reason, the ecotoxicity of flax-fiber-reinforced epoxy composite with or without caffeine was tested in the present study. Prepared samples of the composite material were tested on freshwater green algal species (Hematococcus pluvialis), yeasts (Saccharomyces cerevisae), and crustacean species (Daphnia magna). Aqueous eluates were prepared from the studied material (with caffeine addition (12%) and without caffeine and pure flax fibers), which were subjected to chemical analysis for the residues of caffeine or metals. The results indicate the presence of caffeine up to 0.001 mg/L. The eluate of the studied material was fully toxic for daphnids and partially for algae and yeasts, but the presence of caffeine did not increase its toxicity statistically significantly, in all cases. The final negative biological effects were probably caused by the mix of heavy metal residues and organic substances based on epoxy resins released directly from the tested composite material. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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16 pages, 14653 KiB  
Article
Influence of Light Conditions on the Antibacterial Performance and Mechanism of Waterborne Fluorescent Coatings Based on Waterproof Long Afterglow Phosphors/PDMS Composites
by Sinan Hao, Yuhong Qi and Zhanping Zhang
Polymers 2023, 15(19), 3873; https://doi.org/10.3390/polym15193873 - 24 Sep 2023
Viewed by 1063
Abstract
Marine microbial adhesion is the fundamental cause of large-scale biological fouling. Low surface energy coatings can prevent marine installations from biofouling; nevertheless, their static antifouling abilities are limited in the absence of shear forces produced by seawater. Novel waterborne antifouling coatings inspired by [...] Read more.
Marine microbial adhesion is the fundamental cause of large-scale biological fouling. Low surface energy coatings can prevent marine installations from biofouling; nevertheless, their static antifouling abilities are limited in the absence of shear forces produced by seawater. Novel waterborne antifouling coatings inspired by fluorescent coral were reported in this paper. Waterproof long afterglow phosphors (WLAP) were introduced into waterborne silicone elastomers by the physical blending method. The composite coatings store energy during the day, and the various colors of light emitted at night affect the regular physiological activities of marine bacteria. Due to the synergistic effect of fouling-release and fluorescence antifouling, the WLAP/polydimethylsiloxane (PDMS) composite coating showed excellent antifouling abilities. The antibacterial performance of coatings was tested under simulated day-night alternation, continuous light, and constant dark conditions, respectively. The results illustrated that the antibacterial performance of composite coatings under simulated day-night alternation conditions was significantly better than that under continuous light or darkness. The weak lights emitted by the coating can effectively inhibit the adhesion of bacteria. C-SB/PDMS showed the best antibacterial effect, with a bacterial adhesion rate (BAR) of only 3.7%. Constant strong light also affects the normal physiological behavior of bacteria, and the weak light of coatings was covered. The antibacterial ability of coatings primarily relied on their surface properties under continuous dark conditions. The fluorescent effect played a vital role in the synergetic antifouling mechanism. This study enhanced the static antifouling abilities of coatings and provided a new direction for environmentally friendly and long-acting marine antifouling coatings. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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13 pages, 2077 KiB  
Article
Enhancing Sustainability: Jute Fiber-Reinforced Bio-Based Sandwich Composites for Use in Battery Boxes
by Mina Arya, Else-Marie Malmek, Thomas Koch Ecoist, Jocke Pettersson, Mikael Skrifvars and Pooria Khalili
Polymers 2023, 15(18), 3842; https://doi.org/10.3390/polym15183842 - 21 Sep 2023
Viewed by 1079
Abstract
The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers’ substantial production potential and cost-efficiency have propelled current research in this field. [...] Read more.
The rising industrial demand for environmentally friendly and sustainable materials has shifted the attention from synthetic to natural fibers. Natural fibers provide advantages like affordability, lightweight nature, and renewability. Jute fibers’ substantial production potential and cost-efficiency have propelled current research in this field. In this study, the mechanical behavior (tensile, flexural, and interlaminar shear properties) of plasma-treated jute composite laminates and the flexural behavior of jute fabric-reinforced sandwich composites were investigated. Non-woven mat fiber (MFC), jute fiber (JFC), dried jute fiber (DJFC), and plasma-treated jute fiber (TJFC) composite laminates, as well as sandwich composites consisting of jute fabric bio-based unsaturated polyester (UPE) composite as facing material and polyethylene terephthalate (PET70 and PET100) and polyvinyl chloride (PVC) as core materials were fabricated to compare their functional properties. Plasma treatment of jute composite laminate had a positive effect on some of the mechanical properties, which led to an improvement in Young’s modulus (7.17 GPa) and tensile strength (53.61 MPa) of 14% and 8.5%, respectively, as well as, in flexural strength (93.71 MPa) and flexural modulus (5.20 GPa) of 24% and 35%, respectively, compared to those of JFC. In addition, the results demonstrated that the flexural properties of jute sandwich composites can be significantly enhanced by incorporating PET100 foams as core materials. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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15 pages, 4169 KiB  
Article
Enhancing the Interfacial Shear Strength and Tensile Strength of Carbon Fibers through Chemical Grafting of Chitosan and Carbon Nanotubes
by Jingyue Xiao, Huigai Li, Munan Lu, Yuqiong Wang, Jin Jiang, Wengang Yang, Shuxuan Qu and Weibang Lu
Polymers 2023, 15(9), 2147; https://doi.org/10.3390/polym15092147 - 30 Apr 2023
Cited by 1 | Viewed by 2130
Abstract
Multi-scale “rigid-soft” material coating has been an effective strategy for enhancing the interfacial shear strength (IFSS) of carbon fibers (CFs), which is one of the key themes in composite research. In this study, a soft material, chitosan (CS), and a rigid material, carbon [...] Read more.
Multi-scale “rigid-soft” material coating has been an effective strategy for enhancing the interfacial shear strength (IFSS) of carbon fibers (CFs), which is one of the key themes in composite research. In this study, a soft material, chitosan (CS), and a rigid material, carbon nanotubes (CNTs), were sequentially grafted onto the CFs surface by a two-step amination reaction. The construction of the “rigid-soft” structure significantly increased the roughness and activity of the CFs surface, which improved the mechanical interlocking and chemical bonding between the CFs and resin. The interfacial shear strength (IFSS) of the CS- and CNT-modified CFs composites increased by 186.9% to 123.65 MPa compared to the desized fibers. In addition, the tensile strength of the modified CFs was also enhanced by 26.79% after coating with CS and CNTs. This strategy of establishing a “rigid-soft” gradient modulus interfacial layer with simple and non-destructive operation provides a valuable reference for obtaining high-performance CFs composites. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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13 pages, 2891 KiB  
Article
Improvement of Mechanical Properties and Solvent Resistance of Polyurethane Coating by Chemical Grafting of Graphene Oxide
by Guotao Liang, Fengbiao Yao, Yanran Qi, Ruizhi Gong, Rui Li, Baoxuan Liu, Yueying Zhao, Chenglong Lian, Luming Li, Xiaoying Dong and Yongfeng Li
Polymers 2023, 15(4), 882; https://doi.org/10.3390/polym15040882 - 10 Feb 2023
Cited by 5 | Viewed by 1734
Abstract
Waterborne polyurethane coatings (WPU) are widely used in various types of coatings due to their environmental friendliness, rich gloss, and strong adhesion. However, their inferior mechanical properties and solvent resistance limit their application on the surface of wood products. In this study, graphene [...] Read more.
Waterborne polyurethane coatings (WPU) are widely used in various types of coatings due to their environmental friendliness, rich gloss, and strong adhesion. However, their inferior mechanical properties and solvent resistance limit their application on the surface of wood products. In this study, graphene oxide (GO) with nanoscale size, large surface area, and abundant functional groups was incorporated into WPU by chemical grafting to improve the dispersion of GO in WPU, resulting in excellent mechanical properties and solvent resistance of WPU coatings. GO with abundant oxygen-containing functional groups and nanoscale size was prepared, and maintained good compatibility with WPU. When the GO concentration was 0.7 wt%, the tensile strength of GO-modified WPU coating film increased by 64.89%, and the abrasion resistance and pendulum hardness increased by 28.19% and 15.87%, respectively. In addition, GO also improved the solvent resistance of WPU coatings. The chemical grafting strategy employed in this study provides a feasible way to improve the dispersion of GO in WPU and provides a useful reference for the modification of waterborne wood coatings. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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10 pages, 1530 KiB  
Article
A Functionalized Polysaccharide from Sphingomonas sp. HL-1 for High-Performance Flocculation
by Haolin Huang, Jingsong Li, Weiyi Tao and Shuang Li
Polymers 2023, 15(1), 56; https://doi.org/10.3390/polym15010056 - 23 Dec 2022
Cited by 1 | Viewed by 980
Abstract
The characterization and flocculation mechanism of a biopolymer flocculant produced by Sphingomonas sp. HL-1, were investigated. The bio-flocculant HL1 was identified as an acidic polysaccharide, mainly composed of glucose, and also contained a small amount of mannose, galacturonic acid and guluronic acid. The [...] Read more.
The characterization and flocculation mechanism of a biopolymer flocculant produced by Sphingomonas sp. HL-1, were investigated. The bio-flocculant HL1 was identified as an acidic polysaccharide, mainly composed of glucose, and also contained a small amount of mannose, galacturonic acid and guluronic acid. The flocculating activity of the purified HL1 polysaccharide could be activated by trivalent cations, and its flocculation mechanism was mainly charge neutralization and bridging. The working concentration of fermentation broth HL1 in a kaolin suspension was only 1/10,000 (v/v), in which the polysaccharide concentration was about 2 mg/L. The bio-flocculant HL1 maintained high efficiency at a wide range of pH (pH 3–10). It also exhibited good flocculating activity at a temperature range of 20–40 °C; it could even tolerate high salinity and kept activity at a mineralization degree of 50,000 mg/L. Therefore, the bio-flocculant HL1 has a good application prospect in the treatment of wastewater over a broad pH range and in high salinity. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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12 pages, 2188 KiB  
Article
Acrylic Resin Filling Cell Lumen Enabled Laminated Poplar Veneer Lumber as Structural Building Material
by Xudong Gao, Yiliang Liu, Yanran Qi, Ruizhi Gong, Fengbiao Yao, Jiajia Luo, Yueying Zhao, Yong Dai, Jinguo Wang, Chenglong Lian, Xiaoying Dong and Yongfeng Li
Polymers 2022, 14(23), 5277; https://doi.org/10.3390/polym14235277 - 02 Dec 2022
Cited by 3 | Viewed by 1417
Abstract
Wood is a viable alternative to traditional steel, cement, and concrete as a structural material for building applications, utilizing renewable resources and addressing the challenges of high energy consumption and environmental pollution in the construction industry. However, the vast supply of fast-growing poplar [...] Read more.
Wood is a viable alternative to traditional steel, cement, and concrete as a structural material for building applications, utilizing renewable resources and addressing the challenges of high energy consumption and environmental pollution in the construction industry. However, the vast supply of fast-growing poplar wood has bottlenecks in terms of low strength and dimensional stability, making it difficult to use as a structural material. An environmentally friendly acrylic resin system was designed and cured in this study to fill the poplar cell cavities, resulting in a new type of poplar laminated veneer lumber with improved mechanical strength and dimensional stability. The optimized acrylic resin system had a solid content of 25% and a curing agent content of 10% of the resin solid content. The cured filled poplar veneer gained 81.36% of its weight and had a density of 0.69 g/cm3. The static flexural strength and modulus of elasticity of the further prepared laminated veneer lumber were 123.12 MPa and 12,944.76 MPa, respectively, exceeding the highest flexural strength required for wood structural timber for construction (modulus of elasticity 12,500 MPa and static flexural strength 35 MPa). Its tensile strength, impact toughness, hardness, attrition value, water absorption, water absorption thickness expansion, and water absorption width expansion were 58.81%, 19.50%, 419.18%, 76.83%, 44.38%, 13.90%, and 37.60% higher than untreated laminated veneer lumber, demonstrating improved mechanical strength and dimensional stability, significantly. This method provides a novel approach to encouraging the use of low-value-added poplar wood in high-value-added structural building material applications. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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15 pages, 4063 KiB  
Article
Structure of Waste Hemp Stalks and Their Sound Absorbing Properties
by Shuang Su, Yuan Gao, Xinghai Zhou, Xiaoqing Xiong, Ying Wang and Lihua Lyu
Polymers 2022, 14(22), 4844; https://doi.org/10.3390/polym14224844 - 10 Nov 2022
Cited by 9 | Viewed by 1326
Abstract
To broaden the application fields of waste hemp stalks, the macromolecular, supramolecular, and morphological structures of waste hemp stalks were analyzed, and the relationship between these properties and the sound absorption properties of the hemp stalks was explored. Then, waste hemp stalk/polycaprolactone sound-absorbing [...] Read more.
To broaden the application fields of waste hemp stalks, the macromolecular, supramolecular, and morphological structures of waste hemp stalks were analyzed, and the relationship between these properties and the sound absorption properties of the hemp stalks was explored. Then, waste hemp stalk/polycaprolactone sound-absorbing composite materials were prepared by the hot pressing method. The influence of hemp stalk length and mass fraction, and the density and thickness of the composite materials on the sound absorption properties of composites prepared with the hot pressing temperature set to 140 °C, the pressure set to 8 MPa, and the pressing time set to 30 min was investigated. The results showed that, when the sound energy acts on the hemp stalk, the force between the chain segments, the unique hollow structure, and the large specific surface, act together to attenuate the sound energy and convert it into heat and mechanical energy in the process of propagation, to produce a good sound absorption effect. When the hemp stalk length and mass fraction were set to 6 mm and 50%, respectively, and the density and thickness of the material were set to 0.30 g/cm3 and 1.5 cm, respectively, the average sound absorption coefficient of the waste hemp stalk/polycaprolactone sound-absorbing composite material was 0.44, the noise reduction coefficient was 0.42, the maximum sound absorption coefficient was 1.00, and the sound-absorbing band was wide. The study provided an experimental and theoretical basis for the development of waste hemp stalk/polycaprolactone sound-absorbing composite materials, and provided a new idea for the recycling of the waste hemp stalk. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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Review

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24 pages, 2545 KiB  
Review
Recent Developments and Formulations for Hydrophobic Modification of Carrageenan Bionanocomposites
by Rubie Mavelil-Sam, Elizabeth Mariya Ouseph, Marco Morreale, Roberto Scaffaro and Sabu Thomas
Polymers 2023, 15(7), 1650; https://doi.org/10.3390/polym15071650 - 26 Mar 2023
Cited by 11 | Viewed by 2541
Abstract
Versatility of the anionic algal polysaccharide carrageenan has long been discussed and explored, especially for their affinity towards water molecules. While this feature is advantageous in certain applications such as water remediation, wound healing, etc., the usefulness of this biopolymer is extremely limited [...] Read more.
Versatility of the anionic algal polysaccharide carrageenan has long been discussed and explored, especially for their affinity towards water molecules. While this feature is advantageous in certain applications such as water remediation, wound healing, etc., the usefulness of this biopolymer is extremely limited when it comes to applications such as food packaging. Scientists around the globe are carrying out research works on venturing diverse methods to integrate hydrophobic nature into these polysaccharides without compromising their other functionalities. Considering these foregoing studies, this review is designed to have an in-depth understanding of diverse methods and techniques adopted for tuning the hydrophobic nature of carrageenan-based bionanocomposites, both via surface alterations or by changes made to their chemical structure and attached functional groups. This review article mainly focuses on how the hydrophobicity of carrageenan bionanocomposites varies as a function of the type and refinement of carrageenan, and with the incorporation of additives including plasticisers, nanofillers, bioactive agents, etc. Incorporation of nanofillers such as polysaccharide-based nanoparticles, nanoclays, bioceramic and mineral based nanoparticles, carbon dots and nanotubes, metal oxide nanoparticles, etc., along with their synergistic effects in hybrid bionanocomposites are also dealt with in this comprehensive review article. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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15 pages, 339 KiB  
Review
A Review of the Use of Coconut Fiber in Cement Composites
by Flávia Regina Bianchi Martinelli, Francisco Roger Carneiro Ribeiro, Markssuel Teixeira Marvila, Sergio Neves Monteiro, Fabio da Costa Garcia Filho and Afonso Rangel Garcez de Azevedo
Polymers 2023, 15(5), 1309; https://doi.org/10.3390/polym15051309 - 06 Mar 2023
Cited by 20 | Viewed by 17241
Abstract
The use of plant fibers in cementitious composites has been gaining prominence with the need for more sustainable construction materials. It occurs due to the advantages natural fibers provide to these composites, such as the reduction of density, fragmentation, and propagation of cracks [...] Read more.
The use of plant fibers in cementitious composites has been gaining prominence with the need for more sustainable construction materials. It occurs due to the advantages natural fibers provide to these composites, such as the reduction of density, fragmentation, and propagation of cracks in concrete. The consumption of coconut, a fruit grown in tropical countries, generates shells that are improperly disposed of in the environment. The objective of this paper is to provide a comprehensive review of the use of coconut fibers and coconut fiber textile mesh in cement-based materials. For this purpose, discussions were conducted on plant fibers, the production and characteristics of coconut fibers, cementitious composites reinforced with coconut fibers, cementitious composites reinforced with textile mesh as an innovative material to absorb coconut fibers, and treatments of coconut fiber for improved product performance and durability. Finally, future perspectives on this field of study have also been highlighted. Thus, this paper aims to understand the behavior of cementitious matrices reinforced with plant fibers and demonstrate that coconut fiber has a high capacity to be used in cementitious composites instead of synthetic fibers. Full article
(This article belongs to the Special Issue Sustainable Polymer Composites from Renewable Resources: Functionality and Applications)
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