Modifications and Applications of Natural Polymer Materials and Its Derivatives

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 (15 August 2023) | Viewed by 17340

Special Issue Editor

Department of Chemical Engineering, Materials & Environment, Sapienza – University of Rome, Via Eudossiana 18, 00184 Rome, Italy
Interests: advanced oxidation processes; green processes; agroindustrial waste valorization; biochemical engineering; microalgae; pesticide removal; wastewater treatment; value-added compounds
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Special Issue Information

Petroleum-based plastics are restricted by petrochemical raw materials and their harmful effects on the ecological environment. Natural polymers are widely found in animals and plants, such as cellulose, starch, protein, lignin, natural rubber, nucleic acid, etc. Natural polymers as well as their derivatives are bio-renewable and biodegradable, and environmentally friendly. However, pure natural polymer materials often do not meet people's increasing and diverse needs. Therefore, research on the modification of natural polymers, natural polymer derivatives and the application performance has a great value. This Special Issue focuses on this topic, aiming to collect the latest research articles and communications, as well as comprehensive reviews, etc.

Published Papers (5 papers)

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Research

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15 pages, 3495 KiB  
Article
Process Design for Value-Added Products in a Biorefinery Platform from Agro and Forest Industrial Byproducts
by Nicolás M. Clauser, Fernando E. Felissia, María C. Area and María E. Vallejos
Polymers 2023, 15(2), 274; https://0-doi-org.brum.beds.ac.uk/10.3390/polym15020274 - 05 Jan 2023
Viewed by 1224
Abstract
Agroforestry wastes are industrial byproducts available locally such as eucalyptus sawdust (EUC) and sugarcane bagasse (SCB). These byproducts can be used as lignocellulosic raw materials to produce high-value products. This study is a techno–economic analysis of four potential scenarios to produce polyhydroxybutyrate (PHB) [...] Read more.
Agroforestry wastes are industrial byproducts available locally such as eucalyptus sawdust (EUC) and sugarcane bagasse (SCB). These byproducts can be used as lignocellulosic raw materials to produce high-value products. This study is a techno–economic analysis of four potential scenarios to produce polyhydroxybutyrate (PHB) and levulinic acid (LA) from hemicellulosic sugars by a fermentative pathway in a biomass waste biorefinery. Mass and energy balances were developed, and technical and economic assessments were carried out to obtain gas, char, and tar from residual solids from autohydrolysis treatment. It was determined that microbial culture could be an attractive option for added-value product production. More than 1500 t/year of PHB and 2600 t/year of LA could be obtained by the proposed pathways. Microbial and enzymatic conversion of LA from sugars could significantly improve energy consumption on the conversion strategy. The products from solid residual valorization (char and tar) are the most important for economic performance. Finally, a variation in specific variables could mean substantial improvements in the final indicators of the processes, reaching a higher NPV than USD 17 million. Full article
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16 pages, 3029 KiB  
Article
Histological and Molecular Evidence of the Positive Performance of Glycerol-Plasticized Chitosan-Alginate Membranes on Skin Lesions of Hyperglycemic Mice
by Flavia Figueiredo Azevedo, Thiago Anselmo Cantarutti, Paula de Freitas Rosa Remiro, Beatriz Barbieri, Rafael Abboud Azoubel, Mariana Harue Taniguchi Nagahara, Ângela Maria Moraes and Maria Helena Melo Lima
Polymers 2022, 14(21), 4754; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14214754 - 06 Nov 2022
Cited by 2 | Viewed by 1636
Abstract
The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment [...] Read more.
The purpose of this study was to investigate tissue repair of excisional wounds in hyperglycemic animals treated with chitosan-alginate membranes (CAM) produced in the presence of glycerol. 8-week C57B1 male mice were divided into normoglycemic animals with a 0.9% saline solution topical treatment (CTSF); hyperglycemic animals with 0.9% saline solution topical treatment (DMSF) and hyperglycemic animals with glycerol-plasticized chitosan-alginate membrane topical treatment (DMCAM). On post-wound day three, the DMCAM group presented a lower number of leukocytes, mature mastocytes, a higher number of vessels (p < 0.05), and active mastocytes (p < 0.05) when compared to the CTSF and DMSF groups. There were no differences regarding the distribution, deposition, organization, and thickness of collagen fibers. On day 7 there were no differences in the analysis of fibroblasts, mastocytes, and TGF−β1 and VEGF expressions among the groups. Regarding collagen fibers, the DMCAM group presented slight red-orange birefringence when compared to the CTSF and DMSF groups. On day 14 there was a slight concentration of thinner elastic fibers for the DMCAM group, with a greater reorganization of papillary skin and improved red-orange birefringence collagen fibers, as well as net-shaped orientation, similar to intact skin. In addition, improved elastic fiber organization distributed in the entire neo-dermis and a larger presence of elaunin fibers were observed, in a similar pattern found in the intact skin. The use of CAM in cutaneous lesions boosted tissue repair since there was a smaller number of inflammatory cells and mastocytes, and an improvement in collagen deposition and collagen fibers. These results demonstrate the high potential of plasticized chitosan-alginate membrane for skin wound dressing of hyperglycemic patients. Full article
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16 pages, 2641 KiB  
Article
Investigating the Mechanical Properties and Durability of Asphalt Mixture Modified with Epoxidized Natural Rubber (ENR) under Short and Long-Term Aging Conditions
by Gailan Ismat Safaeldeen, Ramez A. Al-Mansob, Abdulnaser M. Al-Sabaeei, Nur Izzi Md Yusoff, Amiruddin Ismail, Wah Yen Tey, Wan Nur Aifa Wan Azahar, Ahmad Nazrul Hakimi Ibrahim and Taha Mohammed Jassam
Polymers 2022, 14(21), 4726; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14214726 - 04 Nov 2022
Cited by 5 | Viewed by 1881
Abstract
Modifiers such as fibers, fillers, natural and synthetic polymer extenders, oxidants and anti-oxidants, and anti-stripping agents are added to produce modified asphalt. However, polymers are the most widely utilized modifiers to enhance the function of asphalt mixtures. The objective of this research was [...] Read more.
Modifiers such as fibers, fillers, natural and synthetic polymer extenders, oxidants and anti-oxidants, and anti-stripping agents are added to produce modified asphalt. However, polymers are the most widely utilized modifiers to enhance the function of asphalt mixtures. The objective of this research was to evaluate the mechanical properties and durability of epoxidized natural rubber (ENR)-modified asphalt mix under short- and long-term aging conditions. The physical and rheological characteristics of the base asphalt and ENR-modified asphalt (ENRMA) were tested. In order to evaluate the mechanical properties and durability of the modified mixtures, the resilient modulus of the ENR–asphalt mixtures under unaged, and short- and long-term aging conditions at various temperatures and frequencies was obtained. Furthermore, the resistance to moisture damage of asphalt mixtures was investigated. The findings showed that the stiffness of the ENR–asphalt mixes increased because of the mutual influence of short- and long-term aging on the mixes. In addition, ENR reduced the susceptibility to moisture damage. The stiffness of the mixes was influenced by the temperature and frequencies. By using mathematical modelling via the multivariable power least squares method, it was found that temperature was the dominant factor among all other factors. The results suggested that the durability of asphalt pavements is improved by using ENR. Full article
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18 pages, 3010 KiB  
Article
Red Beetroot and Banana Peels as Value-Added Ingredients: Assessment of Biological Activity and Preparation of Functional Edible Films
by Danijela Šeremet, Ksenija Durgo, Anamaria Komljenović, Mihaela Antolić, Ana Mandura Jarić, Ana Huđek Turković, Draženka Komes and Božidar Šantek
Polymers 2022, 14(21), 4724; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14214724 - 04 Nov 2022
Cited by 5 | Viewed by 2457
Abstract
In the present study, water extracts from banana and red beetroot peels were evaluated as a potential source of biologically active compounds for the formulation of edible films. Using spectrophotometric and HPLC-DAD methodologies, banana peel extract was found to be a valuable source [...] Read more.
In the present study, water extracts from banana and red beetroot peels were evaluated as a potential source of biologically active compounds for the formulation of edible films. Using spectrophotometric and HPLC-DAD methodologies, banana peel extract was found to be a valuable source of dopamine (156.08 mg L−1), while red beetroot peel extract was abundant in red-violet pigments betacyanins (90.1 mg betanin L−1). The biological activity of the extracts was studied by determining their effects on macromolecular models, including DNA (plasmid phiX RF1 DNA), protein (bovine serum albumin), and lipid (linoleic acid) models, as well as on continuous human cell lines of colon cancer Caco-2 and hepatocellular liver cancer Hep G2 at concentrations of 0.2 and 1 mg mL−1. Results showed that the extracts had no adverse effects and both were further used for the formulation of edible films using alginate in combination with three types of plant proteins—rice, peanut, and pumpkin. In general, edible films based on banana peel extract were characterized by better bioactive properties compared with the films based on red beetroot peel extract. The addition of peanut proteins into the formulations resulted in the most desirable bioactive profile of the formulated edible films, including total phenolic content and antioxidant capacity. Aside from the control sample prepared only with the alginate, the highest dopamine content was determined in the film with incorporated pumpkin proteins (10.72 mg g−1 dw), while the sample prepared with peanut proteins was richest in betacyanins (175.58 mg betanin g−1 dw). Full article
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Review

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28 pages, 2880 KiB  
Review
Chitin, Chitosan, and Nanochitin: Extraction, Synthesis, and Applications
by Michael Kozma, Bishnu Acharya and Rabin Bissessur
Polymers 2022, 14(19), 3989; https://0-doi-org.brum.beds.ac.uk/10.3390/polym14193989 - 23 Sep 2022
Cited by 28 | Viewed by 8309
Abstract
Crustacean shells are a sustainable source of chitin. Extracting chitin from crustacean shells is ongoing research, much of which is devoted to devising a sustainable process that yields high-quality chitin with minimal waste. Chemical and biological methods have been used extensively for this [...] Read more.
Crustacean shells are a sustainable source of chitin. Extracting chitin from crustacean shells is ongoing research, much of which is devoted to devising a sustainable process that yields high-quality chitin with minimal waste. Chemical and biological methods have been used extensively for this purpose; more recently, methods based on ionic liquids and deep eutectic solvents have been explored. Extracted chitin can be converted into chitosan or nanochitin. Once chitin is obtained and modified into the desired form, it can be used in a wide array of applications, including as a filler material, in adsorbents, and as a component in biomaterials, among others. Describing the extraction of chitin, synthesis of chitosan and nanochitin, and applications of these materials is the aim of this review. The first section of this review summarizes and compares common chitin extraction methods, highlighting the benefits and shortcomings of each, followed by descriptions of methods to convert chitin into chitosan and nanochitin. The second section of this review discusses some of the wide range of applications of chitin and its derivatives. Full article
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