Polymer Degradation and Stability最新文献

英文中文

Electrochemical Degradation Strategies for Polystyrene Microplastic: Current Trends and Future Prospects

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-29 DOI: 10.1016/j.polymdegradstab.2025.111351

Gokul Gangadharan P , Anand Bharti , Abhijit Mondal

Polystyrene (PS) microplastic (MP) pollution is a major environmental issue due to its extensive use, persistence, toxicity and resistance to degradation. In aquatic ecosystems, PS-MP disrupt biodiversity, accumulate in marine organisms, and transport toxic pollutants, ultimately entering the food chain and posing serious ecological and health risks. Conventional removal methods, including filtration, flotation, coagulation, adsorption, and bioremediation, often struggle with inefficiencies, high costs, and secondary pollution. Likewise, degradation techniques such as biodegradation, photocatalysis, and thermal or chemical treatments face challenges related to effectiveness, prolonged treatment durations, and sustainability. Electro-oxidation (EO) has emerged as an efficient and advanced approach for PS-MP breakdown, leveraging reactive oxygen species (ROS) to achieve high removal rates with minimal environmental impact. This review explores recent progress in electrochemical degradation, emphasizing reactor design, electrode materials, operating conditions, mass transfer, mixing strategies, and temperature control. Additionally, degradation pathways and economic feasibility are critically examined. This study systematically evaluates EO performance, with removal efficiencies ranging from 28% to 90% over treatment durations of 3 to 72 hours. PS-MP sizes between 0.1 and 149 µm and concentrations from 10 to 2000 mg/L were assessed. Notably, the BDD anode with 0.03 M Na₂SO₄ as the electrolyte demonstrated superior efficiency, reinforcing its effectiveness in MP degradation. Key challenges and future research directions are discussed to improve EO's practical application. By addressing existing gaps and limitations, this review contributes to the development of sustainable solutions for mitigating PS-MP pollution and safeguarding aquatic ecosystems.

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引用次数: 0

Depolymerization/functionalization of silicones in mild conditions: A “Back-to-polymers” strategy to turn wastes into up-cycled polymers

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-29 DOI: 10.1016/j.polymdegradstab.2025.111343

Antoine Forens , Aurélie Boulègue-Mondière , Fabien Dupin , Nicolas Durand , Daniel Portinha , Etienne Fleury

Silicones based on polydimethylsiloxanes are widely-spread materials owing to their exceptional mechanical, thermal and chemical properties and biocompatibility, among other characteristics. As for any other man-made plastics, recycling silicone-based materials appears essential to transition to a more sustainable production model, lowering the amount of waste that is then turned into valuable building blocks. While conventional processes of chemical recycling of silicones generally describe the recovery of cyclic organosiloxane monomers, herein we introduce an efficient and robust method that produces polymers instead with limited amount of produced cycles (<2 wt%). It relies on reactions carried out at room temperature that use 4-dodecylbenzene sulfonic acid combined with dialkysiloxanes as chain transfer agents. When starting from a polydimethylsiloxane oil, linear polymer chains are obtained with molecular weight lower than the one of the initial substrates, that can be tuned by both the acid and dialkysiloxane contents. A variety of end-cappers (molecular, oligomeric or polymeric; non-functionalized or functionalized with Si-vinyl or Si-H groups) were successfully used, and a mechanism in agreement with the experimental results is suggested. Our method not only applied on silicone oils but also on filler-free crosslinked polymers and some manufactured silicone elastomers. It is shown that when functionalized with either Si-vinyl or Si-H groups, the so-called “recycled” polymers can act as reactive precursors for the preparation of novel silicone elastomer by hydrosilylation reaction. An example of an elastomer made from 100 % recycled silicones is presented. Therefore, our approach represents a robust way to obtain reactive silicone precursors by “upgrading” initially inert oils or by “upcycling” products originally intended to scrap, and in this sense can contribute to enriching circular models for silicone materials.

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引用次数: 0

To improve the flame retardancy, mechanical properties, and water resistance of PC/ABS alloy by a polydimethylsiloxane

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-28 DOI: 10.1016/j.polymdegradstab.2025.111347

Yujie Kang , Yangming Zou , Xinqi Di, Jing Yang, Jun Sun, Hongfei Li, Xiaoyu Gu, Sheng Zhang

PC/ABS alloy is widely used because of its excellent impact strength, size stability, and easy processability. However, it is a dilemma to simultaneously maintain good flame retardancy and mechanical performance. In this work, a combined filler system composed of hydroquinone bis(diphenyl phosphate) (HDP) and polydimethylsiloxane (PDMS) is used to cope with this trouble. By use of 8 wt. %HDP/4 wt. % PDMS in PC/ABS (80/20), the sample achieves a UL-94 V-0 rating and a limiting oxygen index (LOI) of 26.0 %, and the flame retardancy is mostly kept even after water immersion, ascribed to the good hydrophobicity of PDMS. The synergistic flame retardancy action of HDP/ PDMS should be their promotion on charring, that is quantificationally documented from the residue left in the TGA test. The impact strength of the PC/ABS sample containing 8 wt. %HDP/4 wt. % PDMS is 18.8 KJ/m², about 4 times higher than the impact strength of PC/ABS/12 wt. % HDP. After soaking in water for 7 days, the impact strength drops to 8.8 KJ/m² and 1.2 KJ/m², respectively. Comparatively, the severe loss on impact strength by using HDP is mitigated by partial substitution by PDMS, even after soaking in water. This work tries to find feasible solutions referring to flame retardancy and mechanical performance in PC/ABS alloy.

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引用次数: 0

Switchable ion-induced (bio)degradation of a novel polylactic acid composite including microfibrillated cellulose and calcium alginate

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-28 DOI: 10.1016/j.polymdegradstab.2025.111350

Patricia Wolf, Julian Helberg, Cordt Zollfrank

Polylactic acid (PLA) is a bio-based and potentially biodegradable polymer. However, the degradation of this polyester in the natural environment is rather poor. An improvement in its biodegradation behavior is crucial for common and future applications of PLA. In our study, we present biocomposites based on PLA, microfibrillated cellulose (MFC), and calcium alginate. PLA acts as a matrix polymer, the MFC accounts for mechanical reinforcement, and the calcium alginate represents a trigger for initializing biodegradation of the composite under specific conditions (switch). With this composite, a biodegradation test in soil and a weathering test was performed. The composites show a decrease in tensile strength compared to pure PLA. In the presence of monovalent cations like Na⁺ or K⁺ (trigger), the additive calcium alginate forms a hydrogel, what causes fracturing of the composite from the inside out due to volume expansion. The increased water uptake of the alginate hydrogel improves the accessibility of the sample for the microbiome. In soil, the ion-induced effect was initiated by the addition of a PBS buffer, and an increased microbial activity (CO₂ formation) was observed. During weather exposure, the monovalent cations contained in rainwater led to alginate swelling and increased the PLA chains' hydrolysis. For the PLA-MFC-Alginate composites, a decrease of

\overline{M_{w}}

from initially 2.26 × 10⁵ g mol^-1 to 8.50 × 10⁴ g mol^-1 was detected. Meanwhile, neat PLA showed no environmental degradation at all under these conditions. The improved hydrolysis caused by expanded alginate may be a promising first step towards enhanced (bio)degradation of PLA.

聚乳酸（PLA）是一种生物基聚合物，具有生物降解的潜力。然而，这种聚酯在自然环境中的降解能力很差。改善其生物降解性能对于聚乳酸的常见应用和未来应用至关重要。在我们的研究中，我们提出了基于聚乳酸、微纤维素（MFC）和海藻酸钙的生物复合材料。聚乳酸作为基质聚合物，MFC 起到机械增强的作用，而海藻酸钙则是在特定条件下启动复合材料生物降解的触发器（开关）。对这种复合材料进行了土壤中的生物降解试验和风化试验。与纯聚乳酸相比，复合材料的拉伸强度有所下降。在 Na+ 或 K+ 等单价阳离子（触发器）存在的情况下，添加剂海藻酸钙形成水凝胶，由于体积膨胀，导致复合材料从内向外断裂。海藻酸钙水凝胶的吸水性增加，从而提高了微生物群对样本的可及性。在土壤中，加入 PBS 缓冲液后，离子诱导效应开始产生，并观察到微生物活动增加（二氧化碳的形成）。在天气暴露期间，雨水中含有的单价阳离子导致海藻酸膨胀，并增加了聚乳酸链的水解。对于聚乳酸-MFC-海藻酸盐复合材料，检测到其 Mw‾ 从最初的 2.26 × 105 g mol-1 降至 8.50 × 104 g mol-1。与此同时，纯聚乳酸在这些条件下完全没有出现环境降解。膨胀海藻酸盐改善了水解作用，这可能是增强聚乳酸（生物）降解的第一步。

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引用次数: 0

Cyclotriphosphazene based epoxy vitrimer with excellent recyclability and flame retardancy

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-27 DOI: 10.1016/j.polymdegradstab.2025.111346

Daquan Wang , Zuoliang Zhang , Xin Xu , Yao Qiu , Gang Chang , Kaiyun Yuan , Ruqing Xu , Lingjie Meng

The widespread application of epoxy resins in thermosetting materials is limited by inadequate flame retardancy and recyclability. This study reports the synthesis of a bio-based, hexafunctional star-shaped epoxy cyclotriphosphazene (NEP) via nucleophilic substitution and oxidation of hexachlorocyclotriphosphazene and eugenol. An intrinsically flame-retardant epoxy vitrimer (EV/NEP) was subsequently prepared, exhibiting superior mechanical properties, heat resistance, and thermal stability. Incorporation of 9 mol % NEP significantly enhanced flame retardancy, increasing the limiting oxygen index (LOI) to 26.2 % while reducing peak heat release rate (PHRR) and total smoke release (TSR) by 24.9 % and 35.4 %, respectively. Flame retardancy mechanisms were elucidated in both solid and gas phases. Recyclability was confirmed through solvent recovery and thermal compression experiments. Dynamic ester bonds conferred excellent shape memory properties to EV/NEP. The combination of flame retardancy and recyclability makes this epoxy vitrimer a promising candidate for aerospace and automotive applications.

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引用次数: 0

Synthesis of crosslinkers based on octa vinyl polyhedral oligomeric silsesquioxane and their flame retardant applications in silicone rubber

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-26 DOI: 10.1016/j.polymdegradstab.2025.111344

Zijian Zheng , Haibo Fan , Wenyuan Zhang , Liang Qiao , Fan Yang , Rongjie Yang , Wenchao Zhang

It is challenging to improve the flame retardancy and thermal stability of silicone rubber. An effective method was proposed here to solve this problem by incorporating crosslinker made of octa vinyl polyhedral oligomeric silsesquioxane (OV-POSS) into condensed room temperature curing silicone rubber (PDMS). Meanwhile, OV-POSS with different numbers of crosslinking groups were also applied to PDMS and effectively improved its flame retardancy and thermal stability. With the addition of 10 phr nC-POSS (an OV-POSS has an average of n participating click response groups, including 2,4,6,8C-POSS), silicone rubber (SR-nCPOSS) passed the V-0 rating in the vertical combustion test (UL-94) with a high limiting oxygen index (LOI) value of 31–32 %. Moreover, compared with silicone rubber (SR) using tetraethyl orthosilicate, the peak heat release rate was reduced by 46 % and the initial decomposition temperature under nitrogen was increased from 460 °C to 568 °C. In addition, the possible flame-retardant mechanism of nC-POSS, the flame-retardant and catalytic charring effects and free radical quenching effects of PDMS multi-crosslinked networks, were further revealed. The multi-crosslinked network formed by nC-POSS could inhibit the main chain decomposition caused by the terminal hydroxyl group at low temperatures and promote the crosslinking charring of SR, which effectively increased the service temperature of silicone rubber. Moreover, nC-POSS inhibited thermal degradation of SR in the condensed phase and quenches reactive radicals in the gas phase by generating rigid core radicals and phenyl radicals. Our results provide a simple new method for the fabrication of silicone rubber with excellent thermal stability and flame retardancy.

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引用次数: 0

A review of ceramizable EPDM composites: Current status and future perspectives

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-26 DOI: 10.1016/j.polymdegradstab.2025.111345

Xu Du , Fuping Li , Feng Qin , Jiabao Chu , Wei Dang , Xu Hu , Xinyuan Zhang , Kang Zhao , Yufei Tang

Ceramizable EPDM composites have great applications in the fields of aerospace, automotive, power and energy industry due to their low density, high filling capacity, and exceptional aging and heat resistance. Additionally, ceramizable EPDM composites can form stable ceramic phases at elevated temperature and thus possess superior ablation resistance in comparison with traditional EPDM composites. This paper endeavors to summarize the current status and future perspectives of ceramizable EPDM composites, including the ceramization methods, mechanical properties, thermal insulation and ablation resistance. Currently, ceramization methods for EPDM composites mainly consist of the addition of reinforcing fillers and graft modification. The characteristics of different reinforcing fillers such as granular fillers, fiber fillers and carbon nanofillers are discussed, focusing on the preparation process and filler/EPDM compatibility. In addition, the mechanical properties, thermal insulation and ablation resistance achieved by different ceramization methods together with the strengthening and ablative mechanism are analytically compared and discussed. Tensile strength reinforced by granular fillers is lower than that of fiber fillers due to their poor compatibility, while carbon nanomaterials endow EPDM composites with better ablation resistance but poor thermal insulation because of the permeable networks. Graft modification can improve the mechanical properties and thermal insulation, but it is limited by the lower ceramic yield. The recorded data and proposed analysis would provide fundamental guidance for the design and development of novel ceramizable EPDM composites.

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引用次数: 0

Enzymatic depolymerization of polyamides (nylons): current challenges and future directions

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-25 DOI: 10.1016/j.polymdegradstab.2025.111341

Shengwei Sun

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.

引用次数: 0

Investigation on active rejuvenation mechanism of aged SBS modified bitumen: Insights from experiments and molecular dynamics

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-24 DOI: 10.1016/j.polymdegradstab.2025.111336

Song Xu , Xiangjie Niu , Shaoxu Cai , Bingtao Xu , Lei Fang , Zhilong Cao , Canlin Zhang , Hongyan Ma

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.

{"title":"Investigation on active rejuvenation mechanism of aged SBS modified bitumen: Insights from experiments and molecular dynamics","authors":"Song Xu , Xiangjie Niu , Shaoxu Cai , Bingtao Xu , Lei Fang , Zhilong Cao , Canlin Zhang , 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}

引用次数: 0

Analysis of liquid products and mechanism of thermal/catalytic pyrolysis of polypropylene

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-03-23 DOI: 10.1016/j.polymdegradstab.2025.111338

Lu Yao , Jianhua Zhu , Shuyuan Li , Yue Ma , Changtao Yue

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.

引用次数: 0

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