Polymer Degradation and Stability最新文献

{"title":"Enzymatic depolymerization of polyamides (nylons): current challenges and future directions","authors":"Shengwei Sun","doi":"10.1016/j.polymdegradstab.2025.111341","DOIUrl":"10.1016/j.polymdegradstab.2025.111341","url":null,"abstract":"<div><div>Environmental accumulation of polyamide (nylon) waste is a pressing global issue. Microbial enzyme-mediated biodegradation serves as the most attractive and eco-friendly approach for the sustainable management of end-of-life nylons. However, it is hampered by inefficient degradation rates and a limited knowledge of potential enzymes and mechanisms. Given its significance, this review aims to provide a comprehensive overview of the advancements in enzymatic nylon depolymerization, their mechanisms, their challenges, and their opportunities. The review can then inform protein engineering and enhance the discovery of novel nylon-degrading enzymes.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111341"},"PeriodicalIF":6.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on active rejuvenation mechanism of aged SBS modified bitumen: Insights from experiments and molecular dynamics","authors":"Song Xu ,&nbsp;Xiangjie Niu ,&nbsp;Shaoxu Cai ,&nbsp;Bingtao Xu ,&nbsp;Lei Fang ,&nbsp;Zhilong Cao ,&nbsp;Canlin Zhang ,&nbsp;Hongyan Ma","doi":"10.1016/j.polymdegradstab.2025.111336","DOIUrl":"10.1016/j.polymdegradstab.2025.111336","url":null,"abstract":"<div><div>SBS modified bitumen (SMB) is widely used for its excellent physical and rheological properties, but it is susceptible to aging due to exposure to environmental factors such as heat, light, and oxygen. This aging process involves bitumen aging and SBS degradation, which complicates the rejuvenation of SMB. In order to explore the rejuvenation mechanism of aged SMB, particularly emphasizing the rejuvenation effects of epoxy compounds (BUDGE, TMPGE, and RDGE), a combination of molecular dynamics simulation and experiments was employed. The thermodynamic, chemical, and physical properties of rejuvenated SMB were analyzed. Results show that BUDGE and its repaired SBS exhibit excellent flexibility compared to TMPGE, improving cohesive energy density and free volume of aged bitumen, which facilitates recovery of ductility in aged SMB. Conversely, SBS repaired with RDGE increases cohesive energy density of aged SMB while reducing free volume, which enhances stiffness of bitumen. Additionally, rigid groups in RDGE inhibit mobility of both itself and the repaired SBS, leading to a reduction in the ductility of aged SMB to 10.1 cm. Besides, SBS repaired with RDGE shows strongest binding with resins and aromatics, which diminishes lubricating effect of these components on asphaltenes. This reduction in lubrication enhances aggregation of asphaltenes, ultimately raising flow resistance.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111336"},"PeriodicalIF":6.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705344","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}

{"title":"Analysis of liquid products and mechanism of thermal/catalytic pyrolysis of polypropylene","authors":"Lu Yao ,&nbsp;Jianhua Zhu ,&nbsp;Shuyuan Li ,&nbsp;Yue Ma ,&nbsp;Changtao Yue","doi":"10.1016/j.polymdegradstab.2025.111338","DOIUrl":"10.1016/j.polymdegradstab.2025.111338","url":null,"abstract":"<div><div>Rapid thermal and catalytic pyrolysis of polypropylene (PP) were carried out using Py-GC/MS. The distribution of products of rapid pyrolysis and the influence of FCC catalyst on pyrolysate production were studied both qualitatively and quantitatively at the temperature of 500 °C. The corresponding reaction pathways were suggested based on the experimental results. The results showed that the olefin content of PP cracking products exceeded 99 wt. %, which were monoolefines with carbon number of 3n and diolefins with carbon number of 3n+1, respectively, and only a very small amount of alkanes. The catalyst promoted the formation of monolefine and decreased the content of diolefin. With the addition of catalyst, the content of small molecular weight monolefine between C9 and C21 increased by 13.6 wt. %, while the diolefin content of C15+ decreased to varying degrees. The thermal and catalytic pyrolysis of PP can be reasonably explained using free radical mechanism and carbonium ion mechanism, respectively.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111338"},"PeriodicalIF":6.3,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705347","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}

{"title":"Degradation of multicomponent phosphate-plasticized PVC under thermal aging at moderate temperature","authors":"Mathilde Larrieu ,&nbsp;Nathalie Balcar ,&nbsp;Gilles Barabant ,&nbsp;Maroussia Duranton ,&nbsp;Odile Fichet ,&nbsp;Sophie Cantin","doi":"10.1016/j.polymdegradstab.2025.111339","DOIUrl":"10.1016/j.polymdegradstab.2025.111339","url":null,"abstract":"<div><div>Given the limited literature on the aging of multicomponent phosphate-plasticized polyvinylchloride (p-PVC), studies are needed to better understand the degradation mechanisms of such materials. To this end, p-PVC was formulated with three plasticizers: 12.5 % phosphate plasticizer, 17.5 % Diisodecyl Phthalate (DIDP), and 1.8 % Epoxidized Soybean Oil (ESBO). An additional 2.5 wt % of pigment paste was also added to half of the samples. To mimic real environment in which such materials can be present, the p-PVC films underwent artificial aging through temperature cycling (48 h at 80 °C, 24 h at 25 °C, with a constant relative humidity of 65 %). Yellowing was observed as the dominant colour change, with the metallic stabilizer contributing to a greenish hue at the start of aging. The study of plasticizer migration demonstrated that mainly the phosphate plasticizer was lost from the samples over 300 days of aging, while the DIDP and ESBO contents remained largely stable. Thus, phosphate diffusion coefficient in PVC of 4–6 × 10^–15 m²/s has been measured, which has not yet been reported in the literature. Finally, the pigment showed no effect on dehydrochlorination nor plasticizer loss, but contributed to conceal the sample yellowing.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111339"},"PeriodicalIF":6.3,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724326","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}

{"title":"Effect of repeated thermoplastic processing of polypropylene matrix on the generation of low-molecular-weight compounds","authors":"Andrea Polachova,&nbsp;Jaroslav Cisar,&nbsp;Martin Novak,&nbsp;Miroslava Dusankova,&nbsp;Vladimir Sedlarik","doi":"10.1016/j.polymdegradstab.2025.111337","DOIUrl":"10.1016/j.polymdegradstab.2025.111337","url":null,"abstract":"<div><div>This study investigates the effects of repeated reprocessing on polypropylene (PP) and the associated release of low-molecular-weight substances into liquid and gaseous phases. Specifically, virgin polypropylene (Mosten TB 003) was mechanically reprocessed 1, 5, 10, 15, and 18 times to simulate its participation in the mechanical recycling cycle. The mechanical properties of all PP samples were evaluated, along with their potential migration into water. The stability of PP was assessed using differential scanning calorimetry (DSC), while molecular weight distribution was determined via high-temperature gel permeation chromatography (GPC) with refractometric and viscosimetric detection. GPC and DSC analyses of PP's mechanical properties revealed that reprocessing led to chain shortening and reduced thermal stability, evidenced by material yellowing. For PP recycled 18 times—representing the maximum feasible number of reprocessing cycles—the molecular weight decreased by approximately 30 % compared to virgin PP. The potential release of volatile substances (odorants) into the environment during PP processing was monitored using headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC–MS). Two extraction temperatures were examined: 90 °C, simulating the maximum temperature PP reaches indoors, and 120 °C, representing outdoor conditions. The least volatile substances were detected in the most extensively reprocessed PP (18x). At 120 °C, the most significant compounds identified included phenolic substances such as 2,4-di‑tert-butylphenol, 2,6-di‑tert‑butyl‑p-benzoquinone, 4-hydroxybenzaldehyde, estragole, and 2-phenoxyethanol. The number of reprocessing cycles was indicated by the presence of 4-methyl-1,6-heptadien-4-ol.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111337"},"PeriodicalIF":6.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143847418","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}

{"title":"Constructing a carborane-hybridized cross-linked network endows phenolic resin with excellent structural thermo-oxidative and ablative resistant","authors":"Chen Qiu,&nbsp;Liwei Yan,&nbsp;Yisen Huang,&nbsp;Ran Xu,&nbsp;Fenglin Wang,&nbsp;Huawei Zou,&nbsp;Yinfu Luo,&nbsp;Mei Liang","doi":"10.1016/j.polymdegradstab.2025.111335","DOIUrl":"10.1016/j.polymdegradstab.2025.111335","url":null,"abstract":"<div><div>Phenolic resin (PR) has been widely used in ablative thermal protection systems for aerospace applications, but improving its thermo-oxidative and ablation resistance remains challenging. PR hybrid resin with excellent thermal-oxidative resistance was designed through introducing carborane (CB) into the cross-linked network structure of PR. CB hybrid phenolic resin (CBPR) displayed an impressive heat resistance and carbonization, the initial thermal decomposition temperature (T_{5 %}) and weight residue at 800 °C (R_{800 °C}) of CBPR_0.4 in N₂ were 566.3 °C and 85.45 %, and those were 494.5 °C and 79.74 % in air. It was related to the fact that CB could consume free radicals, inhibit cross-linking network destruction, promote organic-inorganic hybrid structures generation and slow down decomposition rate. Meanwhile, PR hybrid resin possessed outstanding oxyacetylene ablation performance, the linear ablation rate (LAR) and mass ablation rate (MAR) were only 0.0015 mm/s and 0.0375 g/s due to in-situ ceramicization and graphitization during ablation, which were reduced by 98.26 % and 71.88 %. The results of this study would provide some inspirations for the development of high-performance thermally protective materials in the future.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111335"},"PeriodicalIF":6.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705346","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}

{"title":"The impact of heat and humidity on unplasticized poly(vinyl chloride)","authors":"Marwa Saad ,&nbsp;Marek Bucki ,&nbsp;Sonia Bujok ,&nbsp;Dominika Pawcenis ,&nbsp;Tjaša Rijavec ,&nbsp;Karol Górecki ,&nbsp;Łukasz Bratasz ,&nbsp;Irena Kralj Cigić ,&nbsp;Matija Strlič ,&nbsp;Krzysztof Kruczała","doi":"10.1016/j.polymdegradstab.2025.111334","DOIUrl":"10.1016/j.polymdegradstab.2025.111334","url":null,"abstract":"<div><div>The thermal degradation at 60 °C and 80 °C of unplasticized poly(vinyl chloride), PVC, was comprehensively investigated through the application of numerous spectroscopic techniques, as well as contact angle measurements (CA), dynamic mechanical analysis (DMA), and size-exclusion chromatography (SEC). To study the effect of relative humidity (RH) on the deterioration of unplasticized PVC, two regimes of accelerated degradation experiments were selected: low RH (max. 20 % RH) and high RH = 60 %, which corresponds to usually the highest RH in heritage institutions equipped with an HVAC system. Nuclear magnetic resonance (NMR) analysis revealed no substantial alterations in the material during its degradation for up to 20 weeks. This finding suggests that no significant branching or crosslinking occurred, which was confirmed by SEC measurements. Notable changes were observed in the Raman and UV–Vis spectra, indicative of the formation of conjugated carbon-carbon double bonds through dehydrochlorination. The formation of polyenes was responsible for the yellowing of samples, characterized with a CIELab color analyzer. Notwithstanding, the aforementioned changes did not lead to a notable decline in the mechanical properties, as evidenced by DMA measurements. Electron paramagnetic resonance (EPR) spectroscopy demonstrated the formation of stable radicals even at 60 °C, and in the sample degraded at 80 °C the presence of radicals was evident. This indicates that a radical degradation mechanism cannot be excluded even at such low temperatures, prevailing at higher relative humidity values. A summary of employed methods was prepared as a guideline for heritage scientists, considering the invasiveness and destructiveness of the techniques and their outcomes.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111334"},"PeriodicalIF":6.3,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705345","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}

{"title":"Physical properties and chemical structure evolution mechanism of AMPS-based copolymer oil well cement retarder in ultra-high temperature alkaline solution environment","authors":"Hang Zhang ,&nbsp;Xinyang Zhang ,&nbsp;Xiujian Xia ,&nbsp;Miaomiao Hu ,&nbsp;Xinyu Ma ,&nbsp;Yujie Ying ,&nbsp;Pengpeng Li ,&nbsp;Jie Cao ,&nbsp;Yun Cheng ,&nbsp;Jintang Guo","doi":"10.1016/j.polymdegradstab.2025.111333","DOIUrl":"10.1016/j.polymdegradstab.2025.111333","url":null,"abstract":"<div><div>2-Acrylamido-2-methylpropanesulfonic acid (AMPS) based copolymer retarder is one of the most commonly used oil well cement additives in cementing engineering. However, its performance decline caused by the thermal degradation behavior in ultra-high temperature (UHT) environment is particularly prominent, and the underlying mechanism remains unclear. In view of this issue, the physical properties and chemical structure evolution mechanism of two kinds of representative oil well cement copolymer retarder, namely the anionic binary copolymer PAI [AMPS-co-itaconic acid (IA)] and the heterocyclic zwitterionic quaternary copolymer PAINM [AMPS-co-IA-co-N-vinylpyrrolidone (NVP)-co-methacrylamido propyl trimethylammonium chloride (MAPTAC)], were comparatively investigated in UHT alkaline solution environment, aiming to provide theoretical guidance for the optimization design strategy of improving the UHT efficiency of retarder in future research. The results indicated that copolymer retarders had significant thermal degradation behavior in UHT alkaline solution environment (<em>T</em> ≥ 200 °C, pH≈13), which was manifested in the decrease of apparent viscosity and viscosity-average molecular weight, the change of pH value, the variation of side groups and the pyrolysis of main chain (producing unsaturated alkenes). Both the hydrolysis of amide bond and the decarboxylation reaction in the copolymer side chains would lead to the configuration transformation of carboxyl from di-carboxyl to mono-carboxyl, and the thermal degradation behavior made the main chain configuration of the aged product severely deviate from the initial structure. The above two factors were the main reasons for the retarding efficiency reduction of copolymers at UHT. Furthermore, the introduction of rigid cyclic and cationic side groups could slightly delay the main chain rupture and the decarboxylation process, but was unable to reverse the thermal degradation progress of the copolymer retarder.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"238 ","pages":"Article 111333"},"PeriodicalIF":6.3,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685889","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}

{"title":"Volatile compounds characterization of microalgae biomass (Chlorella sp. HS2) at high processing temperatures for application to an eco-friendly polymer composite","authors":"Young-Gu Kim ,&nbsp;Joung Sook Hong ,&nbsp;Hsiang-Yu Wang ,&nbsp;Kyung Hyun Ahn","doi":"10.1016/j.polymdegradstab.2025.111330","DOIUrl":"10.1016/j.polymdegradstab.2025.111330","url":null,"abstract":"<div><div>In this study, we investigate the volatile organic compounds release characteristics of microalgae (<em>Chlorella</em> sp. HS2) in relation to temperature in an effort to realize an alternative type of biomass for use in the fabrication of eco-friendly polymer composites. The volatile organic compounds (VOCs) generated during the compounding process of the polymer composite is quantified and the VOC generation pathways are discussed. As the microalgae are heated and their content in the composites increases, the intensity of the VOC release increases. At a high temperature of 180 °C, a typical polymer processing temperature, microalgae release volatile substances. The VOCs are identified as compounds containing ketone functional groups and benzene derivatives through chromatography and spectrometry analyses. VOCs with ketone functional group can originate from small fatty acids by a complex reaction pathway that includes hydrolysis, oxidation, and degradation, while benzene derivatives are from aromatic amino acids, such as Tyrosine, Phenylalanine, and Tryptophan, contained in the microalgae. The findings demonstrate that microalgae biomass particles produce VOCs during polymer processing, which must be considered during the fabrication and eventual commercialization of polymer composites.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"237 ","pages":"Article 111330"},"PeriodicalIF":6.3,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679857","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}

{"title":"Pressure steam ageing of silica filled silicone rubber : Degradation mechanisms","authors":"Manar Ramram ,&nbsp;Lénaïk Belec ,&nbsp;Jean-François Chailan ,&nbsp;François Perseil Rouillard ,&nbsp;François-Xavier Perrin","doi":"10.1016/j.polymdegradstab.2025.111332","DOIUrl":"10.1016/j.polymdegradstab.2025.111332","url":null,"abstract":"<div><div>Silica filled silicone rubber compound was hydrothermally aged under a complex condition consisting of a succession of vacuum phases at 80 °C and exposure to pressure steam at 134 °C. The results from various physico-chemical analysis techniques indicate that hydrothermal ageing has significantly affected both the polymer network and the polymer-filler interfaces, allowing the identification of the primary degradation mechanisms. Solvent swelling and solid ²⁹Si CP-MAS NMR analysis evinced that hydrolytic scission reactions predominate in the early stages of ageing and are compensated by recombination reactions for the subsequent cycles.</div><div>The volatilization of cyclic oligomers, resulting from the backbiting reaction, led to polymer loss and an associated increase in silica content within the silicone rubber compound, as confirmed by FTIR and TGA analyses. Significant changes occurred at the polymer-filler interfaces during the first few hundred cycles, including the formation of covalent bonds at the silica surface, replacing the physical interactions. These findings were further supported by solid-state ²⁹Si CP-MAS NMR analysis and ammonia-modified swelling experiments.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"237 ","pages":"Article 111332"},"PeriodicalIF":6.3,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}