Polymer and Composites: Degradation, Recycling and Application

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 (5 September 2023) | Viewed by 8550

Special Issue Editors

Materials Science and Engineering, School of Chemical and Material Engineering, Jiangnan University, Wuxi, China
Interests: biodegradable polymers; polymer composites; polymer alloy; polymer processing; polymer nanocomposites; polymer crystallization; polymer recycling; functional polymer materials

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Guest Editor
School of Material Science and Engineering, Zhejiang Sci-Tech University, Zhejiang, China
Interests: biobased thermosets; polymer recycling; polymer crystallization

Special Issue Information

Dear Colleagues,

Since the commercialization of plastic products in the 1950s, plastic products have penetrated all areas of our daily life due to their versatile and tailorable properties. Meanwhile, the durability and improper end of life management of plastics and "white pollution" have gradually threatened both the natural environment and the human living environment.

At present, the global total of waste plastics has reached 6.3 billion tons per year. In 1980, 0% of plastic waste was recycled. By 2020, the recycling rate of plastic waste had only increased to about 10%, while the remaining plastic waste was directly landfilled in the natural environment. The accumulating plastic debris has a negative influence on the ecology of the environment and the microplastic particles produced in seawater could also bring carriers of toxic substances, causing health threats to humans.

Reducing the hazards of discarded plastic products and exploring ways to recycle them are also inevitable requirements for solving the problem of plastic pollution, which is attracting more and more attention from scientific researchers.

The aim of this Special Issue is to highlight progress in the degradation and recycling of polymers and composites, bio-based polymers, and biodegradable polymers.

Dr. Pengwu Xu
Dr. Yunsheng Xu
Guest Editors

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Keywords

  • degradation
  • recycling
  • polymer and composites
  • biodegradable polymer
  • bio-based polymer
  • sustainable materials

Published Papers (4 papers)

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Research

10 pages, 3322 KiB  
Article
Study on Rapid Detection Method for Degradation Performance of Polyolefin-Based Degradable Plastics
by Jinglun Zhou, Linlin Li, Dengxu Wang, Lihong Wang, Yuanqi Zhang and Shengyu Feng
Polymers 2023, 15(1), 183; https://doi.org/10.3390/polym15010183 - 30 Dec 2022
Cited by 2 | Viewed by 2061
Abstract
In order to accurately determine the degradation performance of polyolefin-based degradable plastics, the concept of bioassimilated carbon is proposed for the first time in this paper; the bioactive and hydrophilic organic carbon in plastic degradation products is defined as bioassimilation carbon. A method [...] Read more.
In order to accurately determine the degradation performance of polyolefin-based degradable plastics, the concept of bioassimilated carbon is proposed for the first time in this paper; the bioactive and hydrophilic organic carbon in plastic degradation products is defined as bioassimilation carbon. A method for the detection of the carbonyl index and bioassimilated carbon conversion rate in polyolefin degradable plastics was developed to quickly identify its degradation performance. The measurement results show that the bioassimilated carbon conversion rate of more than 70% can be used to replace the biodegradation rate index to achieve the purpose of quickly identifying the degradation performance of plastics. The deterioration detection cycle proposed by the current common standards implemented in American Society of Testing Materials: ASTM D6400 “Specification for Composting Plastics” can be shortened from 1 year to 1 month. The standard system for catalytic degradation of plastics provides detection methods for polyolefin-based catalytic degradation materials (microplastics), and solves the problems of long detection cycle and poor detection efficiency. Thus, this method has promise for use as a relevant standard method for accurately providing a reference for the assessment. Full article
(This article belongs to the Special Issue Polymer and Composites: Degradation, Recycling and Application)
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11 pages, 2329 KiB  
Article
Effect of Recycling on the Mechanical, Thermal and Rheological Properties of Polypropylene/Carbon Nanotube Composites
by Attila Bata, Dorottya Nagy and Zoltán Weltsch
Polymers 2022, 14(23), 5257; https://doi.org/10.3390/polym14235257 - 1 Dec 2022
Cited by 4 | Viewed by 1560
Abstract
In this research the effect of physical recycling on the mechanical, thermal, and rheological properties of polypropylene (PP)/multiwalled carbon nanotube (MWCNT) was investigated. After melt homogenization by extrusion, specimens were injection moulded with 0.1 and 0.5 wt% MWCNT content. The recycling process was [...] Read more.
In this research the effect of physical recycling on the mechanical, thermal, and rheological properties of polypropylene (PP)/multiwalled carbon nanotube (MWCNT) was investigated. After melt homogenization by extrusion, specimens were injection moulded with 0.1 and 0.5 wt% MWCNT content. The recycling process was simulated by multiple grinding and re-moulding, then we compared the behavior of original and recycled PP/MWCNT composites. Differential scanning calorimetry (DSC) measurements proved that MWCNT had double the effect on the morphology of the PP matrix: on the one hand nucleating effect can be detected because 0.5 wt% MWCNT increased the onset temperature of crystallization by 10 °C, compared to the basic PP material; on the other hand, the crystalline fraction of the recycled composite materials decreased compared to the original PP material with the same MWCNT content. This resulted in a slight decrease in strength and stiffness but an increase in elongation at break. However, compared to the original unreinforced PP reference, even the recycled materials have better properties. The mechanical test results showed that recycled PP/MWCNT 0.5 wt% increased the elastic modulus (~15%) and decreased the tensile strain at yield (~10%). However, in the values of tensile stress at yield, relevant difference was not found. It was also shown by oscillatory rheometry that MWCNT had a significant effect on the rheological properties (storage and loss modulus, complex viscosity) of PP compounds in a wide temperature range (190–230 °C). Full article
(This article belongs to the Special Issue Polymer and Composites: Degradation, Recycling and Application)
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12 pages, 2368 KiB  
Article
Effect of Diatomite on the Thermal Degradation Behavior of Polypropylene and Formation of Graphene Products
by Yankun Chen and Biao Wang
Polymers 2022, 14(18), 3764; https://doi.org/10.3390/polym14183764 - 8 Sep 2022
Viewed by 1729
Abstract
In this work, the thermogravimetry–Fourier transform infrared spectroscopy (TG–FTIR) and gas chromatography–mass spectrometry (GC–MS) techniques are used to investigate the thermal degradation behavior of polypropylene (PP) with 20 wt.% diatomite (DM). The initial decomposition temperature of these blends was 17 °C lower than [...] Read more.
In this work, the thermogravimetry–Fourier transform infrared spectroscopy (TG–FTIR) and gas chromatography–mass spectrometry (GC–MS) techniques are used to investigate the thermal degradation behavior of polypropylene (PP) with 20 wt.% diatomite (DM). The initial decomposition temperature of these blends was 17 °C lower than that of pristine PP, and more olefin degradation products were formed during the pyrolysis process under Ar atmosphere. These results could be attributed to the catalytic effects of DM on the degradation of PP and the changes of PP chain scission pathways around the particles (more β scission happened via the secondary radical transfer). These olefins could be caught by DM through the Si–O–C bond formed during the heat–treatment around 400~500 °C. The formation of the cross–linked structure could facilitate the growth of graphene during a high–temperature graphitization process. Full article
(This article belongs to the Special Issue Polymer and Composites: Degradation, Recycling and Application)
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18 pages, 3704 KiB  
Article
Links among Microbial Communities, Soil Properties and Functions: Are Fungi the Sole Players in Decomposition of Bio-Based and Biodegradable Plastic?
by Vusal Guliyev, Benjawan Tanunchai, Matthias Noll, François Buscot, Witoon Purahong and Evgenia Blagodatskaya
Polymers 2022, 14(14), 2801; https://doi.org/10.3390/polym14142801 - 9 Jul 2022
Cited by 6 | Viewed by 2148
Abstract
The incomplete degradation of bio-based and biodegradable plastics (BBPs) in soils causes multiple threats to soil quality, human health, and food security. Plastic residuals can interact with soil microbial communities. We aimed to link the structure and enzyme-mediated functional traits of a microbial [...] Read more.
The incomplete degradation of bio-based and biodegradable plastics (BBPs) in soils causes multiple threats to soil quality, human health, and food security. Plastic residuals can interact with soil microbial communities. We aimed to link the structure and enzyme-mediated functional traits of a microbial community composition that were present during poly (butylene succinate-co-butylene adipate (PBSA) decomposition in soil with (PSN) and without (PS) the addition of nitrogen fertilizer ((NH4)2SO4). We identified bacterial (Achromobacter, Luteimonas, Rhodanobacter, and Lysobacter) and fungal (Fusarium, Chaetomium, Clonostachys, Fusicolla, and Acremonium) taxa that were linked to the activities of ß-glucosidase, chitinase, phosphatase, and lipase in plastic-amended soils. Fungal biomass increased by 1.7 and 4 times in PS and PSN treatment, respectively, as compared to non-plastic amended soil. PBSA significantly changed the relationships between soil properties (C: N ratio, TN, and pH) and microbial community structure; however, the relationships between fungal biomass and soil enzyme activities remained constant. PBSA significantly altered the relationship between fungal biomass and acid phosphatase. We demonstrated that although the soil functions related to nutrient cycling were not negatively affected in PSN treatment, potential negative effects are reasoned by the enrichment of plant pathogens. We concluded that in comparison to fungi, the bacteria demonstrated a broader functional spectrum in the BBP degradation process. Full article
(This article belongs to the Special Issue Polymer and Composites: Degradation, Recycling and Application)
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