Polymer Degradation and Stability最新文献_第3页

Effect of chemical structure on properties evolution and molecular mechanism of polyimide films under ultraviolet irradiation 紫外线照射下聚酰亚胺薄膜化学结构对性能演变的影响及分子机理

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-20 DOI: 10.1016/j.polymdegradstab.2025.111503

Shiqin Xu , Yao Zhang , Zishuo Zhao , Jiayu Zhan , Guofeng Tian , Dezhen Wu

{"title":"Effect of chemical structure on properties evolution and molecular mechanism of polyimide films under ultraviolet irradiation","authors":"Shiqin Xu , Yao Zhang , Zishuo Zhao , Jiayu Zhan , Guofeng Tian , Dezhen Wu","doi":"10.1016/j.polymdegradstab.2025.111503","DOIUrl":"10.1016/j.polymdegradstab.2025.111503","url":null,"abstract":"<div><div>The focus of this work is a detailed comparative study of the changes induced by ultraviolet (UV) irradiation in polyimide (PI) films with different chemical structures. Five synthesized aromatic PI films were subjected to UV irradiation. The properties and structural evolution resulting from this irradiation were comprehensively evaluated using a combination of experiments and simulations. A mechanism for the UV irradiation-induced molecular chain breakage on the surface of PI films was proposed. After 1600 h of UV irradiation, the mechanical properties, heat resistance, and other macroscopic properties of the PI films were maintained at >70 % of their original values, and the surface of the PI films showed damages such as holes and cracks after UV irradiation. The mass loss and thickness loss of PI films caused by UV irradiation exhibited a strong correlation, while the density remained basically unchanged. In addition, an increase in the surface hydrophilicity of the PI films was observed. There was a breakdown of surface –C–C–, –C–N–, and –C–H bonds, accompanied by an increase in the content of –C–O– and –C=O bonds. Based on experimental surface characterization, it was proposed that UV irradiation of PI films primarily occurs at the surface. Molecular simulations were performed to calculate the energy gap to undergo energy level jumps and the energy of the chemical bonds to break for the PI films, and it was hypothesized that the UV irradiation resistance of the PI films is related to the optical transmittance and the ease of charge-transfer complex (CTC) formation.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111503"},"PeriodicalIF":6.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Eco-friendly design of double-layered coated cotton fabrics for dual-functional flame retardancy and electromagnetic interference shielding 环保设计的双层涂层棉织物，具有阻燃和屏蔽电磁干扰双重功能

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-19 DOI: 10.1016/j.polymdegradstab.2025.111494

Congke Gu , Liping Jin , Chenpeng Ji , Yu Guan , Lingxin He , Wei Wang , Wenwen Guo

{"title":"Eco-friendly design of double-layered coated cotton fabrics for dual-functional flame retardancy and electromagnetic interference shielding","authors":"Congke Gu , Liping Jin , Chenpeng Ji , Yu Guan , Lingxin He , Wei Wang , Wenwen Guo","doi":"10.1016/j.polymdegradstab.2025.111494","DOIUrl":"10.1016/j.polymdegradstab.2025.111494","url":null,"abstract":"<div><div>With the rapid development of 5G communication technology, it is essential to develop a multifunctional cotton fabric with both flame retardant and electromagnetic shielding properties for cutting-edge electronic communication equipment. In this study, a high-efficiency flame retardant coating was prepared by a simple one-step method using phosphoric acid, sodium alginate (SA) and MXene as raw materials. Due to the phosphorylated sodium alginate (PSA) catalyzing the charring of cotton fabrics and MXene acting as a physical barrier, the coating exhibited excellent flame retardant efficiency against cotton fabrics at an ultra-low addition of about 4.7 wt% (CT-MP-1 achieved a UL-94 rating of V-0 and a limiting oxygen index (LOI) value of 24 %). After vertical flammability test of CT-MP-3, the limiting oxygen index was reached 35 %, and the length of combustion damage was reduced from 30 cm to 11 cm compared with pure cotton (CT). Thermogravimetric testing proved that CT-MP-3 reaches 10.15 % of char residue at 800°C. Cone calorimeter test showed that the total heat release (THR) and the peak heat release rate (PHRR) of CT-MP-3 decreased by 39.5 % and 84.6 % compared with CT, respectively. In addition, MXene solution is sprayed on the surface of CT-MP-3 as an electromagnetic interference (EMI) shielding layer, so that CT-MP-3-m3 can achieve EMI shielding effect (∼ 20 dB). In conclusion, this study lays a foundation for the preparation of EMI shielding cotton fabrics with excellent flame retardant properties, and provides a new method for EMI shielding and flame retardant of electronic communication equipment.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111494"},"PeriodicalIF":6.3,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel flame-retardant polyurethane coating with self-healing function by photothermal conversion 一种新型的具有自愈功能的光热转化聚氨酯阻燃涂料

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-18 DOI: 10.1016/j.polymdegradstab.2025.111499

Yong-Yin Cui , Ming-Yang Zhang , Xiang Li , Liu-Jun Guo , Ya-Kun Cai , Hui-Jing Li , Yan-Chao Wu

{"title":"A novel flame-retardant polyurethane coating with self-healing function by photothermal conversion","authors":"Yong-Yin Cui , Ming-Yang Zhang , Xiang Li , Liu-Jun Guo , Ya-Kun Cai , Hui-Jing Li , Yan-Chao Wu","doi":"10.1016/j.polymdegradstab.2025.111499","DOIUrl":"10.1016/j.polymdegradstab.2025.111499","url":null,"abstract":"<div><div>Polyurethane (PU) materials are widely utilized in the design of self-healing material systems. Due to their poor flame resistance and violent droplet behavior during combustion, challenges remain in achieving PU materials exhibiting self-healing, flame retardancy, and robust mechanical performance. Here, a self-healing flame-retardant composite coating (PU-3) was developed by incorporating PDA@EG, a filler prepared by coating expanded graphite (EG) with polydopamine (PDA), into a PU matrix featuring multiple hydrogen bonds and disulfide bonds. As a photothermal conversion agent, PDA@EG enables PU-3 to achieve rapid photothermal conversion (82.9 °C within 3 min), a toughness repair efficiency of 93.79 % under near-infrared (NIR) light for 10 min, and repeatable self-healing. Additionally, PDA@EG can also act as a flame retardant, mitigating the dripping behavior and increasing the limiting oxygen index (LOI). The essence is as a charring agent to form a completely expanded carbon layer after heating, preventing the exchange of O<sub>2</sub> and heat. The synergistic interaction between PDA@EG and the hydrogen bond/disulfide bond matrix enables the combined self-healing and flame-retardant properties of PU-3. This work provides a heuristic perspective for the design of self-healing flame-retardant coating.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111499"},"PeriodicalIF":6.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144338879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Biosynthesis of poly(glycolate-ran-3-hydroxybutyrate)s with different glycolate molar fractions from ethylene glycol 以乙二醇为原料，不同乙醇酸摩尔分数生物合成聚乙醇酸-氨基-3-羟基丁酸

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-18 DOI: 10.1016/j.polymdegradstab.2025.111502

Munenori Hayashida , Yosuke Ota , Masayoshi Honda , Sumio Aisawa , Yuji Shibasaki , Hideki Abe , Miwa Yamada

{"title":"Biosynthesis of poly(glycolate-ran-3-hydroxybutyrate)s with different glycolate molar fractions from ethylene glycol","authors":"Munenori Hayashida , Yosuke Ota , Masayoshi Honda , Sumio Aisawa , Yuji Shibasaki , Hideki Abe , Miwa Yamada","doi":"10.1016/j.polymdegradstab.2025.111502","DOIUrl":"10.1016/j.polymdegradstab.2025.111502","url":null,"abstract":"<div><div>Glycolate (GL)-based polyhydroxyalkanoates have potential for biomedical and other applications owing to their high hydrodegradability. Here, we established a biosynthetic pathway for the synthesis of random copolymer poly(glycolate-<em>ran</em>-3-hydroxybutyrate) [P(GL-<em>ran</em>-3HB)] from ethylene glycol (EG) contained in industrial wastes in recombinant <em>Escherichia coli</em>. Recombinant <em>E. coli</em> expressing an engineered polyhydroxyalkanoate (PHA) synthase (PhaC) capable of polymerizing GL, two enzymes providing 3HB monomer (PhaA and PhaB), and three enzymes providing GL monomer from EG (FucO, AldA, and PCT) in a medium containing EG and xylose, produced a GL molar fraction in P(GL-<em>ran</em>-3HB) of 0.24±0.003 mol % maximum. Therefore, we split this method into GL- and polymer synthesis, which enabled the increase of the GL molar fraction from 4.5 to 49.5 mol % in P(GL-<em>ran</em>-3HB)s by initial concentrations of EG in the medium; this indicates that EGs derived from industrial waste have a potential for use in P(GL-<em>ran</em>-3HB) synthesis with a variety of GL molar fractions. P(GL-<em>ran</em>-3HB) biosynthesis with a GL molar fraction exceeding 17 mol % was reported for the first time in this study. Polymer characterization revealed that incorporation of the GL unit slightly increased glass transition temperature and decreased melting temperature and molecular weight of P(GL-<em>ran</em>-3HB). A decrease in crystallinity with increasing GL molar fraction was observed, particularly for polymers with GL molar fractions above 46 mol %, which were almost amorphous. Our findings contribute to the expanding application of EG as a new feedstock for PHAs and broadening the applications of novel PHA copolymers.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111502"},"PeriodicalIF":6.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501655","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

End-of-life climate impacts of polyhydroxyalkanoates in the United States: the role of feedstock variability and temporal dynamics - a systematic review 美国聚羟基烷酸酯的寿命终止气候影响：原料变异性和时间动态的作用-一项系统综述

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-18 DOI: 10.1016/j.polymdegradstab.2025.111500

Seyedehniloufar Mousavi , Tristan Brown , Robert W. Malmsheimer , Deepak Kumar , Jenny Frank

{"title":"End-of-life climate impacts of polyhydroxyalkanoates in the United States: the role of feedstock variability and temporal dynamics - a systematic review","authors":"Seyedehniloufar Mousavi , Tristan Brown , Robert W. Malmsheimer , Deepak Kumar , Jenny Frank","doi":"10.1016/j.polymdegradstab.2025.111500","DOIUrl":"10.1016/j.polymdegradstab.2025.111500","url":null,"abstract":"<div><div>Biobased and biodegradable bioplastics, such as polyhydroxyalkanoates (PHAs), offer a sustainable alternative to petroleum-based plastics, addressing the growing concerns associated with plastic waste. At the same time, their end-of-life (EoL) pathways play a critical role in determining their overall sustainability. This work compares previous studies that report the climate impacts of various EoL pathways of PHA using Life Cycle Assessment (LCA) strategies which are based in the United States. These pathways include landfilling, recycling, incineration, composting, and anaerobic digestion (AD), as assessed using the methodological tools WARM, SimaPro, and GREET. Variability driven by feedstock types, such as corn stover vs. sugarcane bagasse, was found to affect solely the recycling pathway, where the polymer’s composition remains unchanged at EoL, but the feedstock type alters the environmental credit value. In contrast, variability across time horizons (GWP20, GWP100, GWP500) was observed to predominantly influence the landfill and AD pathways, with longer horizons amplifying methane-related impacts in landfilling and carbon sequestration benefits in AD. Also, the analysis finds that landfilling has the highest Global Warming Potential (GWP) across all time horizons due to high methane emissions, while recycling offers the most climate benefits by providing credit offset and fitting to a circular economy. Furthermore, the AD pathway has limited modeling efforts in the United States even though it is one of the most studied and predominant in Europe.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111500"},"PeriodicalIF":6.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Polyphenylene sulfide alloying and carbon fiber reinforcing together promote polycarbonate towards superior flame retardant composite with good mechanics 聚苯硫醚合金化和碳纤维增强共同促进聚碳酸酯向性能优良的阻燃复合材料发展

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-18 DOI: 10.1016/j.polymdegradstab.2025.111501

Hao Shang , Yong Qiu , Xuebo Tai , Lin Wang , Lijun Qian , Wei Tang , Jingyu Wang , Wang Xi , Lijie Qu

{"title":"Polyphenylene sulfide alloying and carbon fiber reinforcing together promote polycarbonate towards superior flame retardant composite with good mechanics","authors":"Hao Shang , Yong Qiu , Xuebo Tai , Lin Wang , Lijun Qian , Wei Tang , Jingyu Wang , Wang Xi , Lijie Qu","doi":"10.1016/j.polymdegradstab.2025.111501","DOIUrl":"10.1016/j.polymdegradstab.2025.111501","url":null,"abstract":"<div><div>Advanced composite technology is the motive force to develop of high-performance composite materials, which includes the superior flame retardant composite materials with superior physical and mechanical properties. This work reports the flame retardant behavior and mechanism of short-cut carbon fiber (SCF) and polyphenylene sulfide (PPS) in polycarbonate (PC) matrix, so as to their influence on material mechanics. Individually adding SCF already presented visible effectiveness on suppressing PC combustibility. 6SCF/PC achieved a limited oxygen index (LOI) of 30.0 %, and passed UL94 V-0 rating at 3.2 mm thickness. But when the thickness of specimen reduced to 1.6 mm thickness, 6SCF/PC only passed UL94 V-2 rating. The failure of SCF in shortening self-extinguishing time and anti-dripping was overcome by extra introducing PPS to work together with SCF. 20PPS/6SCF/PC passed UL94 V-1 rating at 1.6 thickness, and achieved a LOI of 33.0 %. Meanwhile, the flame retardant mechanism of SCF and PPS in suppressing PC combustibility was investigated from the charring behavior, the thermal decomposition process and volatile release, and the pyrolytic products of relevant composites. Besides, the additive effect of SCF and PPS in improving the char residue retention and flexural stiffness of composites was also confirmed. Polyphenylene sulfide alloying and carbon fiber reinforcing together promote polycarbonate towards superior flame retardant composite with good mechanics.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111501"},"PeriodicalIF":6.3,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Facile construction of highly efficient MXene-based P-N biomass intumescent flame retardant system to improve the fire safety of EP coating using mechanochemistry 利用机械化学方法快速构建高效mxeni基P-N生物质膨胀阻燃体系，提高EP涂层的防火安全性

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-17 DOI: 10.1016/j.polymdegradstab.2025.111498

Jirui Qu, Biyu Huang, Gaoyuan Li, Wenbo Sun, Haopeng Zhang, Yanyue Shi, Lei Liu, Xilei Chen, Chuanmei Jiao

{"title":"Facile construction of highly efficient MXene-based P-N biomass intumescent flame retardant system to improve the fire safety of EP coating using mechanochemistry","authors":"Jirui Qu, Biyu Huang, Gaoyuan Li, Wenbo Sun, Haopeng Zhang, Yanyue Shi, Lei Liu, Xilei Chen, Chuanmei Jiao","doi":"10.1016/j.polymdegradstab.2025.111498","DOIUrl":"10.1016/j.polymdegradstab.2025.111498","url":null,"abstract":"<div><div>The development of MXene-based epoxy (EP) coatings with superior fireproofing properties has garnered significant attention for aerospace applications. In this study, MXene@PAA was obtained by simultaneously exfoliating multilayer MXene and reacting it with phosphorus-nitrogen (P-N)-containing biomass-derived phytate ammonium (PAA) via a mechanochemical ball-milling approach. This nanohybrid was then incorporated into EP matrix to construct an intumescent flame-retardant system (IFRs) exhibiting exceptional fire safety, thermal shielding, and hydrophobic de-icing performance. Notably, MXene@PAA significantly enhanced the flame retardancy, smoke suppression, and toxicity reduction of EP coatings even at low loading levels. Remarkably, with only 4 wt % MXene@PAA, EP coating achieved a UL-94 V0 rating and a limiting oxygen index (LOI) of 32.8 %. Furthermore, compared to pure EP, the EP-4MXene@PAA sample demonstrated a 77.85 % reduction in peak heat release rate (pHRR), a 38.81 % decrease in total heat release (THR), and 77.71 % and 77.52 % reductions in peak CO (pCOP) and CO<sub>2</sub> production (pCO<sub>2</sub>P), respectively. Meanwhile, the char residue mass increased by 63.96 %, while the expansion height of the char residue layer rose from 0.5 cm to 3.6 cm. In addition, EP-4MXene@PAA not only has significantly better thermal shielding performance, but also has a significantly faster rate of surface ice melting and sliding. This work offers an effective method for creating multifunctional MXene-based nanohybrid and related polymer nanocomposites, showing great potential for next-generation fire-safe aerospace materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111498"},"PeriodicalIF":6.3,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Enhancing the fire barrier performance of cotton fabrics via polyamidoamine-based coatings 聚酰胺基涂料提高棉织物防火性能的研究

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-16 DOI: 10.1016/j.polymdegradstab.2025.111496

Alessandro Beduini , Elisabetta Ranucci , Ickchan Kim , Jenny Alongi , Mauro Zammarano

{"title":"Enhancing the fire barrier performance of cotton fabrics via polyamidoamine-based coatings","authors":"Alessandro Beduini , Elisabetta Ranucci , Ickchan Kim , Jenny Alongi , Mauro Zammarano","doi":"10.1016/j.polymdegradstab.2025.111496","DOIUrl":"10.1016/j.polymdegradstab.2025.111496","url":null,"abstract":"<div><div>This study investigates the potential of enhancing the fire barrier performance of cotton fabrics by combining α-amino acid-based polyamidoamines (PAAs) with different charge distribution, recognized for their char-forming ability, with smectites of varying aspect ratios. To this purpose, various PAAs coating formulations were applied to cotton fabrics and assembled with polyurethane foam within a mockup assembly to be evaluated under forced combustion conditions (75 kW m⁻²) in the Cube test. Preliminary tests on six PAAs and four smectites identified the cationic, arginine-derived PAA (M-ARG), known for its strong interaction with sodium montmorillonite, as the most promising candidate when combined with laponite. While PAAs alone did not significantly improve barrier performance, the M-ARG/laponite combination (total 16 % by mass add-on) delayed foam liquefaction and the release of liquid pyrolyzates from polyurethane foams by about 21 s. The correlation between the results obtained from Cube test and full-scale chair mockup test, confirmed that treated fabrics can delay the fire growth and the heat release peak rate by over two minutes. These findings demonstrate the effectiveness of char-forming nanocomposite coatings in enhancing fire barrier performance and validate the Cube test as a reliable, cost-efficient, and practical method for material development, reducing the reliance on extensive full-scale testing.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111496"},"PeriodicalIF":6.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

In vitro temperature-dependent degradation of polylactic acid: Experimental characterization and neural network-based prediction 体外温度依赖性聚乳酸降解：实验表征和基于神经网络的预测

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-16 DOI: 10.1016/j.polymdegradstab.2025.111497

Soo-Hyun Woo , Na-Im Kim , Jung-Wook Wee

{"title":"In vitro temperature-dependent degradation of polylactic acid: Experimental characterization and neural network-based prediction","authors":"Soo-Hyun Woo , Na-Im Kim , Jung-Wook Wee","doi":"10.1016/j.polymdegradstab.2025.111497","DOIUrl":"10.1016/j.polymdegradstab.2025.111497","url":null,"abstract":"<div><div>To ensure the reliable use of polylactic acid (PLA) as a medical polymer, it is essential to develop a model that can accurately assess the degradation of its mechanical properties under <em>in vitro</em> conditions. In this study, PLA was immersed in phosphate buffered saline at 37 °C to investigate its degradation behavior. A marked decline in tensile strength was observed following an induction period, with surface analysis revealing that diffusion-limited hydrolysis (DLH) characterized by the formation of hydrolysis-induced micro-pits and cracks was the primary degradation mechanism. Chain scission and crystallization behavior resulting from hydrolysis were systematically examined. Using experimental data obtained at elevated temperatures (50, 60, and 70 °C), crystallization kinetics were modeled using the Avrami equation, enabling the development of a predictive relationship between tensile strength and crystallinity. Furthermore, an artificial neural network was employed to construct a model capable of accurately predicting tensile strength across a range of temperatures and exposure durations, thereby enhancing the reliability of PLA for <em>in vitro</em> applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111497"},"PeriodicalIF":6.3,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synergistic flame retardant coatings for carbon fibre-reinforced ε-caprolactam-based polyamide 6 composites: Fire performance and mechanical properties 碳纤维增强ε-己内酰胺基聚酰胺6复合材料的协同阻燃涂料：防火性能和力学性能

IF 6.3 2区化学

Polymer Degradation and Stability Pub Date : 2025-06-15 DOI: 10.1016/j.polymdegradstab.2025.111495

Zsófia Kovács , Andrea Toldy

{"title":"Synergistic flame retardant coatings for carbon fibre-reinforced ε-caprolactam-based polyamide 6 composites: Fire performance and mechanical properties","authors":"Zsófia Kovács , Andrea Toldy","doi":"10.1016/j.polymdegradstab.2025.111495","DOIUrl":"10.1016/j.polymdegradstab.2025.111495","url":null,"abstract":"<div><div>The use of long fibre-reinforced thermoplastic composites is increasing, but a significant drawback is their flammability due to the organic matrix. This study explores the flame retardancy of carbon fibre-reinforced PA6 composites coated via in-mould coating. The matrix and coating were made by anionic ring-opening polymerisation of ε-caprolactam. The flame retardants used were magnesium oxide (MgO), red phosphorus (RP), hexaphenoxycyclotriphosphazene (HPCTP) and expandable graphite (EG). The flammability and fire performance were evaluated using pyrolysis-combustion flow calorimetry (PCFC), mass loss type cone calorimetry, and glow wire flammability index (GWFI) testing, while evolved gases were analysed using laser pyrolysis coupled with Fourier transform infrared spectrometry (LP-FTIR). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis of the solid residues post-combustion revealed the mechanisms responsible for flame retardancy. Flame retardant coatings reduced the peak heat release rate by up to 33 % and the total heat release by up to 40 % compared to the reference sample. The combination of flame retardants containing magnesium or phosphorus with expandable graphite resulted in a synergistic flame retardant effect due to the enrichment of the heteroatoms in the outer char layers, contributing to a more stable intumescent char and protective barrier layer. The LP-FTIR analysis indicated reduced emissions of toxic gases, particularly hydrogen cyanide (HCN) and carbon monoxide (CO), furthermore, it was found that flame retardants reduced the intensity of the peaks associated with C-H vibrations and P-related peaks appeared in the presence of HPCTP and RP. Overall, the combined flame retardant coatings improved the fire safety of carbon fibre-reinforced PA6 composites without compromising mechanical properties and mitigated the negative effect of carbon fibres on char formation.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"240 ","pages":"Article 111495"},"PeriodicalIF":6.3,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0