Polymer Degradation and Stability最新文献_第2页

Self-degradable poly(lactic acid) for accelerated soil biodegradation via enzyme activity-preserving encapsulation 自降解聚乳酸通过酶活性保持包封加速土壤生物降解

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-06 DOI: 10.1016/j.polymdegradstab.2026.111987

Soyeong Lee , Min Jang , Yujin Choi , Mingyeong Jang , Nayoung Kim , Yong Sik Ok , Sung Yeon Hwang

Although poly(lactic acid) (PLA) degrades under industrial composting conditions, its degradation under milder environments is limited. Embedding enzymes, such as proteinase K (PK), into polymer matrices can enhance degradation, yet challenges such as enzyme deactivation during high-temperature extrusion and high enzyme costs hinder practical applications. To overcome these limitations, we develop a hydrophilic, enzyme-compatible matrix with a low melting point and low crystallinity to stably embed enzymes in PLA. This matrix, based on poly(propylene succinate) and calcium carboxymethyl cellulose, enables uniform enzyme dispersion, resulting in a ∼1.8-times increase in catalytic activity, thermal stability up to 150 °C, and the preservation of enzymatic activity for up to 17 days. Enzyme-embedded PLA films containing this matrix exhibit sufficient mechanical properties for packaging applications. Furthermore, the biodegradation rate of these films reaches 40%, which is ∼2.6-times higher than that of PLA under composting conditions. The degradation products show no adverse effects on soil health. This enzyme-mediated degradation system represents a scalable platform with broad applicability for sustainable polymer development.

虽然聚乳酸（PLA）在工业堆肥条件下降解，但其在温和环境下的降解是有限的。将蛋白酶K （PK）等酶嵌入聚合物基质中可以增强降解，但高温挤压过程中酶的失活和酶的高成本等挑战阻碍了实际应用。为了克服这些限制，我们开发了一种具有低熔点和低结晶度的亲水性酶相容基质，以稳定地将酶嵌入PLA中。该基质，基于聚琥珀酸丙烯和羧甲基纤维素钙，使酶分散均匀，导致催化活性提高~ 1.8倍，热稳定性高达150°C，酶活性保存长达17天。含有这种基质的酶包埋PLA薄膜在包装应用中表现出足够的机械性能。此外，这些膜的生物降解率达到40%，比堆肥条件下的PLA高~ 2.6倍。降解产物对土壤健康无不良影响。这种酶介导的降解系统代表了一个可扩展的平台，具有广泛的可持续聚合物开发适用性。

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引用次数: 0

Microstructural evolution and thermal protection mechanism of ceramifiable silicone composites via boron phosphate phase transformation 磷酸硼相变陶瓷化硅基复合材料的显微组织演变及热保护机理

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-10 DOI: 10.1016/j.polymdegradstab.2026.111999

Jingyao Xu , Wanting Song , Sujie Hu , Laibin Zhang , Shuilai Qiu

The pervasive risk of thermal runaway propagation in lithium–ion battery energy storage stations necessitates advanced thermal barrier materials. To address this, we developed a biomimetic silicone matrix composite inspired by volcanic rock strata. This material integrates a zinc borate/black phosphorus flame–retardant system, a silica aerogel insulation network, and an aramid fiber reinforcement. Upon high–temperature exposure, the composite spontaneously forms a dense, coherent boron phosphate (BPO₄) ceramic layer, akin to volcanic rock, which provides exceptional thermal shielding. Experimental results demonstrate outstanding performance: the composite maintains mechanical stability from –40 to 300 °C, reduces surface temperature rise by 75% compared to pure silicone foam, and lowers the peak heat release rate and total smoke production by 52.5% and 47.9%, respectively. In simulated thermal runaway tests, it completely prevented propagation to adjacent cells and reduced mass loss by 66.1%. Mechanistic studies reveal that the performance stems from a synergistic gas–phase and condensed–phase flame–retardant action, coupled with enhanced insulation and interfacial reinforcement. This work presents a promising material solution for enhancing the intrinsic safety of Energy storage power stations.

锂离子电池储能站普遍存在热失控传播的风险，需要先进的热障材料。为了解决这个问题，我们开发了一种仿生硅基复合材料，灵感来自火山岩地层。这种材料集成了硼酸锌/黑磷阻燃系统，硅气凝胶绝缘网络和芳纶纤维增强。高温暴露后，复合材料会自发形成致密、相干的磷酸硼（BPO4）陶瓷层，类似于火山岩，提供了出色的热屏蔽。实验结果表明，该复合材料在-40 ~ 300℃范围内保持机械稳定性，与纯有机硅泡沫相比，表面温升降低了75%，峰值放热率和总产烟率分别降低了52.5%和47.9%。在模拟热失控测试中，它完全阻止了向相邻细胞的传播，并减少了66.1%的质量损失。机理研究表明，这种性能源于气相和凝聚相的协同阻燃作用，以及增强的绝缘性和界面增强。本研究为提高储能电站的本质安全提供了一种有前景的材料解决方案。

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引用次数: 0

New insights into the photodegradation of aromatic polyurea: A spectro-thermo-mechanical characterization study 芳香族聚脲光降解的新见解：光谱-热-机械表征研究

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-03 DOI: 10.1016/j.polymdegradstab.2026.111982

Shiho Kuwashiro , Amritesh Kumar , George Youssef

Polyurea emerged as a strategic material for protective coatings in harsh environments, with widespread adoption in civilian infrastructure and defense-related applications. However, polyurea, including an aromatic backbone that provides structural robustness, is susceptible to environmental stressors during extended deployment, most notably UV radiation. The objective of this research is to provide new insights into the mechanical, thermal, and physicochemical performance of polyurea after extended exposure to ultraviolet irradiation. Polyurea samples exhibited surface cracking and an increase in reduced modulus upon UV exposure, as probed using nanoindentation. The increase in reduced modulus also extends in depth, and the depth at which the elastic modulus increases is proportional to the exposure duration. FT-IR analysis indicated that multiple chemical structures were altered by UV exposure. Most prominent is the cleavage of ester bonds connecting soft and hard segments, as well as the cleavage of aliphatic chains. In addition, in UV-exposed polyurea, hydroperoxide decomposition led to crosslinking via radical recombination, and new hydrogen-bonding structures formed within the hard segments. These phenomena contribute to the increased surface reduced modulus. UV exposure of polyurea also decreased its thermal decomposition temperature, as determined by thermogravimetry and calorimetry. These outcomes challenge previous experimental results and provide novel mechanistic insights that accelerate the development of next-generation protective materials and structures with prolonged deployment durations.

聚脲成为恶劣环境下防护涂料的战略材料，广泛应用于民用基础设施和国防相关应用。然而，聚脲，包括提供结构坚固性的芳香骨架，在长时间部署期间容易受到环境压力的影响，最明显的是紫外线辐射。本研究的目的是为长时间暴露在紫外线照射下的聚脲的机械、热学和物理化学性能提供新的见解。聚脲样品在紫外线照射下表现出表面开裂和降低模量的增加，用纳米压痕探测。减模量的增加也向深度延伸，并且弹性模量增加的深度与暴露时间成正比。傅里叶变换红外光谱分析表明，紫外照射改变了多种化学结构。最突出的是连接软段和硬段的酯键的断裂，以及脂肪链的断裂。此外，在紫外线暴露的聚脲中，氢过氧化物分解通过自由基重组导致交联，并在硬段内形成新的氢键结构。这些现象有助于增加表面还原模量。通过热重法和量热法测定，聚脲暴露在紫外线下也降低了它的热分解温度。这些结果挑战了之前的实验结果，并提供了新的机制见解，加速了下一代防护材料和结构的开发，延长了部署时间。

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引用次数: 0

Shape-stabilized and flame retardant polyethylene glycol composites based on dual cross-linked network for thermal energy storage 基于双交联网络的形状稳定阻燃聚乙二醇储热复合材料

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-05 DOI: 10.1016/j.polymdegradstab.2026.111988

Shushu Xu , Shenghua Yang , Xiaming Feng , Hongyu Yang , Chaojun Wan , Cheng Yan

Polyethylene glycol (PEG), recognized as an environmentally benign phase change energy storage material, offers advantages including high latent heat capacity, stable performance, and biodegradability. However, its inherent flammability, low thermal conductivity, and propensity for molten leakage significantly constrain practical implementation. To address these limitations, expandable graphite (EG) was employed as flame retardant and thermal conductor, while 2-hydroxyethyl methacrylate phosphate (HMP) served as cross-linking agent with flame retardant effect. Upon simple thermally curing, both chemical and physical cross-linking reactions ensued, forming a three-dimensional network structure that substantially improved the dimensional stability of PEG. By varying mass ratios of raw materials, the optimal formulation was determined to comprise 12 wt% EG and 10 wt% HMP. This composite achieved a UL-94 V-0 rating with LOI value of 28.5% in term of flame retardancy, exhibited a melting enthalpy of 132 J/g, and effectively attained shape stabilization. Moreover, thermal stability assessments revealed a significant increase in the decomposition temperature compared to pure PEG, accompanied by enhanced char formation that contributed to the flame retardant efficacy. The gas-phase flame retardant mechanism, involving radical quenching and dilution effects, was confirmed through evolved gas analysis, further supporting the composites’ robustness for energy storage applications.

聚乙二醇（PEG）是一种公认的环保相变储能材料，具有潜热容量高、性能稳定、可生物降解等优点。然而，其固有的可燃性、低导热性和熔融泄漏倾向极大地限制了其实际应用。为了解决这些局限性，采用了可膨胀石墨（EG）作为阻燃剂和导热材料，而甲基丙烯酸2-羟乙基磷酸酯（HMP）作为交联剂具有阻燃效果。在简单的热固化后，化学和物理交联反应随之发生，形成三维网络结构，大大提高了PEG的尺寸稳定性。通过改变原料的质量比，确定了最佳配方，包括12%的EG和10%的HMP。该复合材料达到UL-94 V-0等级，阻燃LOI值为28.5%，熔化焓为132 J/g，并有效地实现了形状稳定。此外，热稳定性评估显示，与纯PEG相比，分解温度显著提高，同时炭的形成增强，这有助于阻燃效果。通过演化气体分析，证实了气相阻燃机理，包括自由基猝灭和稀释效应，进一步支持了复合材料在储能应用中的鲁棒性。

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引用次数: 0

Integrating disulfide linkages and stretching processes in thermoplastic starch/polylactide blends: A model study on retarding retrogradation 热塑性淀粉/聚乳酸共混物中二硫键和拉伸过程的集成：延迟退化的模型研究

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-01-26 DOI: 10.1016/j.polymdegradstab.2026.111962

Piyawanee Jariyasakoolroj , Suttinun Phongtamrug , Patakorn Pilasen , Wanwisa Limphirat , Suwabun Chirachanchai

Thermoplastic starch (TPS) is a promising biodegradable material; however, its practical application is limited by retrogradation, which deteriorates its mechanical and barrier performance. This work presents a model, solvent-free strategy to suppress TPS retrogradation and improve its compatibility with polylactide (PLA) by combining thiol-enabled chemical modification with biaxial orientation (BO). Starch is chemically modified using mercapto acid derivatives and plasticized with glycerol via twin-screw reactive extrusion to produce crosslinkable Mx-TPS, which is subsequently melt-blended with PLA to form precursor sheets and BO films. Processing-induced disulfide formation and partial plasticizer immobilization stabilize TPS, while BO stretching promotes strain-induced crystallization and lamellar alignment in the PLA phase, collectively reducing V_H-type starch crystallization during storage at 6 °C and 50 °C. X-ray diffraction confirms suppressed V_H-type crystallinity, and the resulting films show improved moisture resistance and gas barrier performance. Mercaptosuccinic acid (MS) provides the strongest overall effect, consistent with enhanced interfacial interactions. Compared with BO-PLA/TPS, BO-PLA/MS-TPS films exhibited reduced oxygen permeability from 1153.72 to 589.31 cc·mil/m²·day·atm and water vapor permeability from 159.21 to 68.90 g·mil/m²·day·atm, together with improved tensile performance. This study demonstrates a practical processing concept to enhance the long-term stability and barrier functionality of PLA/TPS-based films for biodegradable packaging applications.

热塑性淀粉（TPS）是一种很有前途的生物降解材料；然而，其实际应用受到老化的限制，使其力学性能和阻隔性能恶化。本研究提出了一种模型化的无溶剂策略，通过将硫醇使能的化学改性与双轴取向（BO）相结合来抑制TPS的退化并改善其与聚乳酸（PLA）的相容性。用巯基酸衍生物对淀粉进行化学改性，并通过双螺杆反应挤出与甘油塑化，得到可交联的Mx-TPS，随后与PLA熔融共混，形成前驱体片和BO膜。加工诱导的二硫化物形成和部分增塑剂固定稳定了TPS，而BO拉伸促进了应变诱导的结晶和PLA相的片层取向，共同减少了vh型淀粉在6°C和50°C储存期间的结晶。x射线衍射证实了抑制的vh型结晶度，所得薄膜具有更好的抗湿性和气体阻隔性能。巯基琥珀酸（MS）提供最强的整体效应，与增强的界面相互作用一致。与BO-PLA/MS-TPS膜相比，BO-PLA/MS-TPS膜的氧透性从1153.72降至589.31 cc·mil/m2·day·atm，水蒸气透性从159.21降至68.90 g·mil/m2·day·atm，拉伸性能有所提高。本研究展示了一种实用的加工概念，以提高PLA/ tps基薄膜的长期稳定性和屏障功能，用于可生物降解包装应用。

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引用次数: 0

Polymerization catalyst is key: Predicting molecular changes during mechanical recycling of phillips and ziegler-natta catalyst high-density polyethylene (HDPE) 聚合催化剂是关键：预测高密度聚乙烯（HDPE）机械回收过程中的分子变化

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-03 DOI: 10.1016/j.polymdegradstab.2026.111981

Alexsandar Arumugam , Jana Zimmermann , Thea Weingartz , Michael Fischlschweiger , Valerian Hirschberg

We present a systematic approach to predict the molecular degradation of high-density polyethylene (HDPE) during mechanical recycling based on the polymerization catalyst. HDPE represents about 12.5 wt % of the polymer world production and is industrially mainly produced by Phillips (P-HDPE) and Ziegler-Natta catalyst (ZN-HDPE). Two blow-moulding P- and ZNHDPE with identical melt flow indices (MFI) were subjected to mechanical recycling at an extrusion temperature of 170 °C and 210 °C, a screw speed of 180 rpm, and recycling times from 10 to 240 min. Chemical and rheological characterization revealed, that despite similar initial melt properties, P-HDPE and ZN- HDPE exhibited fully contrary degradation mechanisms: for recycled P- HDPE at 170 °C and 210 °C, the complex viscosity (|η*|) and the molecular weight drastically increased after 10 min of recycling time due to star-like branching, followed by chain scission at 170 °C, but crosslinking at 210 °C, resulting in unprocessable, rubber-like material. In contrast, recycled ZNHDPE exhibited a continuous drop in molecular weight and in |η*| across all conditions. This work provides a polymerization catalyst-specific framework to predict and engineer thermo-mechanical molecular degradation pathways in HDPE recyclates, paving the way to tailored recycling strategies to obtain value-added materials.

提出了一种基于聚合催化剂的高密度聚乙烯（HDPE）机械回收过程中分子降解的系统预测方法。HDPE约占聚合物世界产量的12.5%，工业上主要由Phillips （P-HDPE）和Ziegler-Natta catalyst （ZN-HDPE）生产。对熔体流动指数（MFI）相同的两种吹塑P-和ZNHDPE进行机械回收，挤出温度分别为170℃和210℃，螺杆转速为180 rpm，回收时间为10 ~ 240 min。化学和流变学表征表明，尽管P-HDPE和ZN- HDPE的初始熔体性质相似，但它们的降解机制完全相反：在170℃和210℃条件下，P-HDPE的复合粘度（|η*|）和分子量在回收10 min后急剧增加，原因是星形支化，随后在170℃发生链断裂，但在210℃发生交联，导致不可加工的类橡胶材料。相比之下，再生ZNHDPE在所有条件下均表现出分子量和|η*|的持续下降。这项工作为预测和设计HDPE回收物中的热机械分子降解途径提供了一个聚合催化剂特异性框架，为定制回收策略以获得增值材料铺平了道路。

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引用次数: 0

Non-migrating multifunctional macromolecular antioxidants based on hyperbranched polyglycerol for thermooxidative and photooxidative stabilization of polyolefins 基于超支化聚甘油的非迁移多功能高分子抗氧化剂用于聚烯烃热氧化和光氧化稳定

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-01-29 DOI: 10.1016/j.polymdegradstab.2026.111974

Katarína Mosnáčková , Bence Sármezey , Anna Vykydalová , Dóra Fecske , Györgyi Szarka , Béla Iván , Jaroslav Mosnáček , György Kasza

Multifunctional macromolecular antioxidants represent environmentally advantageous alternatives to conventional low molecular mass stabilizers for improving the long-term stability of polyolefins, such as polyethylene (PE) and polypropylene (PP), while minimizing additive migration in the surrounding environment. Hyperbranched macromolecules are especially promising for such purposes, due to their high number of functionalities, ease of production and limited migration. In this study, two hyperbranched polyglycerol (HbPG)-based antioxidants (HbPG-AoxAc) with different molar masses were synthesized by covalent attachment of sterically hindered phenolic units via esterification of the hydroxyl groups of HbPG. These macromolecular stabilizers were characterized by GPC, ¹H NMR and UV–Vis spectroscopies, confirming high antioxidant functionality and well-defined composition. Their performance in thermooxidative and photooxidative stabilization of LDPE and PP was systematically explored and compared with conventional low molecular mass stabilizers using chemiluminescence, oxidative induction time (OIT) determined by DSC, UV–Vis and FTIR spectroscopies. The obtained results indicate that the synthesized HbPG-AoxAc macromolecular antioxidants provide significant stabilization against both thermooxidative and photo-induced degradation in the polyolefin matrices, particularly in PP, and exhibit comparable efficiency to Irganox® 1010 and Irganox® HP-136, while outperforming the secondary antioxidant Irgafos® 168. Importantly, hexane extraction tests revealed negligible leaching of the macromolecular antioxidants, in sharp contrast to the extensive migration and loss observed for the low molecular mass reference additives. These findings confirm the potential of the HbPG-based macromolecular antioxidants as effective, low-migration additives for advanced and environmentally friendly polyolefin applications.

多功能大分子抗氧化剂是传统低分子质量稳定剂的环保替代品，可以提高聚烯烃（如聚乙烯（PE）和聚丙烯（PP））的长期稳定性，同时最大限度地减少添加剂在周围环境中的迁移。超支化大分子由于其大量的功能，易于生产和有限的迁移而特别有希望用于此类目的。本研究以高支化聚甘油（HbPG）为基础，通过HbPG羟基的酯化反应，将空间位阻酚单元共价连接，合成了两种不同摩尔质量的超支化聚甘油抗氧化剂（HbPG- aoxac）。这些大分子稳定剂通过GPC， 1H NMR和UV-Vis光谱进行了表征，证实了高抗氧化功能和明确的组成。利用化学发光、氧化诱导时间（OIT）（DSC、UV-Vis和FTIR）等方法，系统地探讨了它们在LDPE和PP的热氧化和光氧化稳定中的性能，并与传统的低分子质量稳定剂进行了比较。结果表明，合成的HbPG-AoxAc大分子抗氧化剂对聚烯烃基体（特别是PP）的热氧化和光诱导降解都具有显著的稳定性，其效率可与Irganox®1010和Irganox®HP-136相媲美，同时优于二级抗氧化剂Irganox®168。重要的是，己烷萃取试验显示，大分子抗氧化剂的浸出可以忽略不计，与低分子质量参考添加剂的广泛迁移和损失形成鲜明对比。这些发现证实了基于hbpg的大分子抗氧化剂作为高效、低迁移的先进环保聚烯烃添加剂的潜力。

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引用次数: 0

A phosphorus/nitrogen-containing additive to simultaneously improve the flame retardant and anti-corrosion of epoxy resins 一种含磷/含氮添加剂，可同时提高环氧树脂的阻燃性和耐腐蚀性

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-01-29 DOI: 10.1016/j.polymdegradstab.2026.111973

Yifang Hua , Xiaobei Li , Salman Khalid , Jun Sun , Shuhui Liu , Lianfeng Wu , Jiang Jing , Xiaoyu Gu , Sheng Zhang

Epoxy resins (EP) suffer from high flammability and poor corrosion resistance, which restrict their application in harsh environments. Herein, a novel phosphorus- and nitrogen-containing additive (MMPADA) was synthesized through the reaction of 3,5-diamino-1,2,4-triazole (DATA) with dimethyl methylphosphonate (DMMP). Remarkably, with only 2 wt.% MMPADA incorporation, the EP coating kept high transparency and exhibited outstanding flame retardancy. The latter was evidenced by a limiting oxygen index of 31.9 % and a UL-94 V-0 rating, and significant reductions in heat and smoke release. Meanwhile, electrochemical impedance spectroscopy (EIS) confirmed that the EP/2%MMPADA coating maintained much higher charge transfer resistance than the control EP, even after 40 days of immersion in 3.5 wt.% NaCl solution, demonstrating superior long-term anticorrosion performance. These results highlighted that incorporating merely 2 wt.% MMPADA endowed EP coatings with excellent transparency, flame retardancy, and corrosion resistance, thereby offering a feasible strategy to extend their service life in demanding environments.

环氧树脂（EP）具有高可燃性和较差的耐腐蚀性，限制了其在恶劣环境中的应用。本文以3,5-二氨基-1,2,4-三唑（DATA）与甲基膦酸二甲酯（DMMP）为原料，合成了一种新型的含磷含氮添加剂（MMPADA）。值得注意的是，仅添加2 wt.%的MMPADA， EP涂层保持了高透明度，并表现出出色的阻燃性。后者的极限氧指数为31.9%，UL-94 V-0等级，热量和烟雾释放显著减少。与此同时，电化学阻抗谱（EIS）证实，EP/2%MMPADA涂层在3.5 wt.% NaCl溶液中浸泡40天后，其电荷转移电阻仍远高于对照EP，表现出优异的长期防腐性能。这些结果表明，仅添加2%的MMPADA就能使EP涂层具有优异的透明度、阻燃性和耐腐蚀性，从而为延长其在苛刻环境中的使用寿命提供了可行的策略。

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引用次数: 0

Inhomogeneous photodegradation of BPA polycarbonate due to light diffraction by pigment particles 双酚a聚碳酸酯在颜料粒子衍射下的不均匀光降解

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-04 DOI: 10.1016/j.polymdegradstab.2026.111986

James E. Pickett , Gudrun A. Hutchins , Jacob P. Pickett

Bisphenol-A polycarbonate (PC) containing pigment particles exhibits distinctive photodegradation patterns after accelerated weathering exposure using a xenon arc lamp. The patterns are caused by diffraction of ultraviolet (UV) light and can be visualized by transmission electron microscopy (TEM) of thin cross sections after staining with RuO₄. Paraboloid shapes much larger than the particles are visible in sections made perpendicular to the surface while circular bullseye patterns are seen in slices parallel to the surface. Diffraction patterns can occur because the UV source is relatively compact and the orientation of the source and specimen surface is fixed. No patterns are visible by TEM in samples after outdoor exposure where the UV is more dispersed and the sun/specimen orientation varies with hour and season. Therefore, the patterns are artifacts of the test method. Comparison of published yellowing, physical property change, and erosion rates for pigmented and unpigmented PC after outdoor and xenon arc exposure suggests diffraction has at most a minor effect on the PC photodegradation rate.

含有颜料颗粒的双酚a聚碳酸酯（PC）在氙弧灯加速风化暴露后表现出独特的光降解模式。这些图案是由紫外线（UV）衍射引起的，用RuO4染色后可以通过透射电子显微镜（TEM）看到薄截面。在垂直于表面的切片中可以看到比颗粒大得多的抛物面形状，而在平行于表面的切片中可以看到圆形的靶心图案。衍射图案可以发生，因为紫外源是相对紧凑的，并且源和样品表面的方向是固定的。在室外暴露后，紫外线更分散，太阳/样品的方向随时间和季节而变化，透射电镜无法看到样品的图案。因此，模式是测试方法的工件。对比已发表的着色PC和未着色PC在室外和氙弧照射后的发黄、物理性质变化和侵蚀速率，表明衍射对PC光降解速率的影响最轻微。

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引用次数: 0

Molecular oxidative/pyrolysis evolution and influence on short-beam shear damage performance of 3D braided composites 三维编织复合材料分子氧化热解演化及其对短束剪切损伤性能的影响

IF 7.4 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2026-05-01 Epub Date: 2026-02-09 DOI: 10.1016/j.polymdegradstab.2026.111994

Yuanyuan Wu , Shuwei Huang , Rui Wang , Zhongwei Li , Baohui Shi

The damage caused by loading along the thickness direction of 3D braided composite is a common failure factor in the service process of their aerospace structural components, especially considering the environmental effect such as oxidative at high temperature. This paper has innovatively counted and analyzed the thermo-oxidative degradation path and productions of the oxidative skin layer and the pyrolysis core layer in 3D carbon fiber/epoxy resin braided composite using reactive molecular dynamic (RMD) method. The resulting influences on the stress and damage evolution in the braided composite were discussed during short-beam shear loading. The results indicate that the freedom volume ratio gradually stabilize for the oxidative skin layer and continuously decline for the pyrolysis core layer, and the values of the former are lower. After aging for 16 days at 180°C, the main oxidative productions include C13-O, C2, C3, C1, H, H₂O, CO₂ and H_2, and the sequence of formation rate is H₂O > CO₂ > H₂. Whereas, the main pyrolytic productions include C14-O, C7, C3, C2, C1, H₂O, CO₂ and H₂, and the sequence of formation rate is H₂O = CO₂ > H₂. The above variations at the molecular scale in the braided composite have reduced the 7.66 ± 0.84% for peak stress and 8.84 ± 0.52% for interlaminar shear strength values. Furthermore, the differences between the oxidative skin layer and the pyrolytic core layer also change the initial damage at the bottom tension end in the composite during loading caused by the more brittle of the oxidative skin layer.

三维编织复合材料沿厚度方向的载荷损伤是其航空航天结构件服役过程中常见的失效因素，特别是考虑到高温氧化等环境影响。采用反应分子动力学（reactive molecular dynamic， RMD）方法，创新性地对三维碳纤维/环氧树脂编织复合材料中氧化皮层和热解芯层的热氧化降解路径和产物进行了统计和分析。讨论了短梁剪切加载对编织复合材料应力和损伤演化的影响。结果表明：氧化皮层的自由体积比逐渐趋于稳定，热解芯层的自由体积比不断下降，且氧化皮层的自由体积比较低；180℃陈化16 d后，主要氧化产物为C13-O、C2、C3、C1、H、H2O、CO2和H2，生成速率顺序为H2O >； CO2 > H2。而主要热解产物为C14-O、C7、C3、C2、C1、H2O、CO2和H2，生成速率顺序为H2O = CO2 > H2。在分子尺度上，上述变化使编织复合材料的峰值应力降低了7.66±0.84%，层间剪切强度降低了8.84±0.52%。此外，氧化皮层与热解核心层之间的差异也改变了复合材料在加载过程中由于氧化皮层更脆而导致的底部张力端初始损伤。

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引用次数: 0