Pub Date : 2025-12-24DOI: 10.1016/j.polymdegradstab.2025.111888
Xue-Min Yang , Qian-Qian Gao , Qian-Ting Wang , Dan Xiao
Aiming to achieving sustainable and efficient interfacial anti-fire catalysis during polymer combustion, a novel bio-based ferrocene-β-cyclodextrin conjugate (FCCD) was synthesized by self-assembly and condensation reactions. The chemical structure and surface morphology of FCCD were confirmed by FTIR, NMR, XRD, SEM, EDS, and XPS. Subsequently, the thermal, mechanical, and fire safety properties of epoxy (EP) with FCCD composites were studied in detail. The results showed the benzene, phenoxy, and cyclopentadiene radicals were generated by FCCD that disrupted combustion chain reactions in the gas phase, while ferrocene-derived radicals were suppressed to the formation of hydrocarbons and aromatic species. In the condensed phase, the formation of a honeycomb-like char layers was promoted through the synergistic pyrolysis of cyclodextrin’s polyhydroxy framework and ferrocene degradation products, providing both thermal shielding and catalytic reinforcement. Mechanistic analysis revealed that FCCD as an interfacial catalysis was operated in both gas and condensed phases, leading to significant anti-fire and smoke suppression behaviors. This work introduces a novel bio-based conjugate catalysis strategy for multifunctional and sustainable fire safety, offering a potential application in building materials, transportation equipment, and electronics.
{"title":"Novel bio-based ferrocene-β-cyclodextrin conjugate as an interfacial anti-fire catalysis to epoxy: Synthesis, characterization, combustion and smoke suppression behaviors","authors":"Xue-Min Yang , Qian-Qian Gao , Qian-Ting Wang , Dan Xiao","doi":"10.1016/j.polymdegradstab.2025.111888","DOIUrl":"10.1016/j.polymdegradstab.2025.111888","url":null,"abstract":"<div><div>Aiming to achieving sustainable and efficient interfacial anti-fire catalysis during polymer combustion, a novel bio-based ferrocene-<em>β</em>-cyclodextrin conjugate (FCCD) was synthesized by self-assembly and condensation reactions. The chemical structure and surface morphology of FCCD were confirmed by FTIR, NMR, XRD, SEM, EDS, and XPS. Subsequently, the thermal, mechanical, and fire safety properties of epoxy (EP) with FCCD composites were studied in detail. The results showed the benzene, phenoxy, and cyclopentadiene radicals were generated by FCCD that disrupted combustion chain reactions in the gas phase, while ferrocene-derived radicals were suppressed to the formation of hydrocarbons and aromatic species. In the condensed phase, the formation of a honeycomb-like char layers was promoted through the synergistic pyrolysis of cyclodextrin’s polyhydroxy framework and ferrocene degradation products, providing both thermal shielding and catalytic reinforcement. Mechanistic analysis revealed that FCCD as an interfacial catalysis was operated in both gas and condensed phases, leading to significant anti-fire and smoke suppression behaviors. This work introduces a novel bio-based conjugate catalysis strategy for multifunctional and sustainable fire safety, offering a potential application in building materials, transportation equipment, and electronics.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111888"},"PeriodicalIF":7.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838545","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}
Pub Date : 2025-12-24DOI: 10.1016/j.polymdegradstab.2025.111880
Jiapeng Fang , Qing Hu , Ziwu Han , Yuanyuan Li , Zhenfei Fu , Shilong Suo , Xiangyang Peng , Zheng Wang , Chunqing He , Pengfei Fang
Corona discharge on high-voltage transmission lines induces the aging of high-temperature vulcanized silicone rubber (HTV-SR), compromising its water resistance. This study investigated the HTV-SR aging mechanism under single-needle corona discharge by modulating the applied voltage to achieve varying corona intensities. Dual Mechanisms of Corona-Induced Aging in HTV were revealed by macromolecular network and chemical structure changes. Under low-intensity corona (4 kV) treatment, HTV-SR exhibited a decrease in swelling ratio and crystallinity, along with a weakening of the Si–C bond absorption peak, while the proportion of the soluble fraction remained largely unchanged. The aging process was dominated by cross‑linking, which restricted the free volume and consequently reduced the water diffusion coefficient. Under high-intensity corona (>7 kV) treatment, HTV-SR showed an increase in swelling ratio and soluble fraction, accompanied by a weakening of the Si–O bond absorption peak. The aging process was primarily characterized by network scission and oxidative degradation, leading to an expansion of free volume and the introduction of hydrophilic hydroxyl groups, thereby accelerating water diffusion. Finite element simulations elucidated electron energy as a critical factor governing the aging mechanism. As corona intensity increases, the proportion of electrons capable of rupturing Si–O bonds gradually exceeds those able to break Si–C bonds, thereby driving the aging behavior from crosslinking toward degradation. These findings provide valuable insights for the prediction of the aging pathway and developing protection strategies for silicone rubber insulating materials.
{"title":"Unveiling the dual mechanisms of corona-induced aging in HTV silicone rubber: Experiment and finite element simulation","authors":"Jiapeng Fang , Qing Hu , Ziwu Han , Yuanyuan Li , Zhenfei Fu , Shilong Suo , Xiangyang Peng , Zheng Wang , Chunqing He , Pengfei Fang","doi":"10.1016/j.polymdegradstab.2025.111880","DOIUrl":"10.1016/j.polymdegradstab.2025.111880","url":null,"abstract":"<div><div>Corona discharge on high-voltage transmission lines induces the aging of high-temperature vulcanized silicone rubber (HTV-SR), compromising its water resistance. This study investigated the HTV-SR aging mechanism under single-needle corona discharge by modulating the applied voltage to achieve varying corona intensities. Dual Mechanisms of Corona-Induced Aging in HTV were revealed by macromolecular network and chemical structure changes. Under low-intensity corona (4 kV) treatment, HTV-SR exhibited a decrease in swelling ratio and crystallinity, along with a weakening of the Si–C bond absorption peak, while the proportion of the soluble fraction remained largely unchanged. The aging process was dominated by cross‑linking, which restricted the free volume and consequently reduced the water diffusion coefficient. Under high-intensity corona (>7 kV) treatment, HTV-SR showed an increase in swelling ratio and soluble fraction, accompanied by a weakening of the Si–O bond absorption peak. The aging process was primarily characterized by network scission and oxidative degradation, leading to an expansion of free volume and the introduction of hydrophilic hydroxyl groups, thereby accelerating water diffusion. Finite element simulations elucidated electron energy as a critical factor governing the aging mechanism. As corona intensity increases, the proportion of electrons capable of rupturing Si–O bonds gradually exceeds those able to break Si–C bonds, thereby driving the aging behavior from crosslinking toward degradation. These findings provide valuable insights for the prediction of the aging pathway and developing protection strategies for silicone rubber insulating materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111880"},"PeriodicalIF":7.4,"publicationDate":"2025-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838507","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}
Pub Date : 2025-12-23DOI: 10.1016/j.polymdegradstab.2025.111877
Ping Wang , Hongyu Tian , Yiyang Zhou , Tongtong Zhang , Shi Dong , Longen Cheng , Wenbin Luo , Li Yang , Wenxiu Liu , Tian Cao , Mingdi Yang , Daosheng Sun
Developing high-performance composites for maglev train cables that combine excellent flame retardancy, mechanical properties and fatigue resistance is currently a significant challenge in special cable industry. Herein, a multifunctional reactive phosphorus nitrogen flame retardants (UPMDM) with flame retardant and filler surface modification functions was synthesized, and it was employed to control the polymer matrix-filler interactions and the microstructure of ethylene-vinyl acetate copolymer (EVA)-based composite during melt blending. Phosphorus-nitrogen composite flame retardant (MH@UPMDM) could be preformed before melt blending or formed in-situ during melt blending by the reaction between the isocyanate group (-NCO) of UPMDM and the hydroxyl group on the surface of magnesium hydroxide (MH), and the effect of processing type (physical blending/chemical grafting/in-situ reaction) on dispersion kinetics of MH in EVA matrix was investigated. The results indicate preformed MH@UPMDM can play a role in rigid crosslinkers to construct organic-inorganic hybrid network, thus effectively control the dispersion kinetics of the fillers and the filler-matrix interaction in the EVA matrix. Compared with EVA/MH composites, the elongation of EVA/MH@UPMDM composites is increased by nearly 2.2-fold, while it also exhibits an excellent fatigue-resistance under 1.0 × 104th cycles. Furthermore, MH@UPMDM can significantly enhance the flame retardant properties of the composites, the limiting oxygen index (LOI) of EVA/MH@UPMDM composite reaches 33.6 %, while its peak heat release rate (PHRR) and total heat release (THR) decreases to 277.82 kW/m2 and 74.71 MJ/m2 from 436.66 kW/m2 and 88.67 MJ/m2 compared to EVA/MH composites, which may be attributed to the multi-phase synergistic flame retardant mechanism of UPMDM.
{"title":"Multifunctional reactive P-N flame retardant for enhanced flame retardancy, mechanical properties and fatigue resistance of EVA-based cable materials via interfacial compatibilization and regional melting refinement of organic-inorganic interface","authors":"Ping Wang , Hongyu Tian , Yiyang Zhou , Tongtong Zhang , Shi Dong , Longen Cheng , Wenbin Luo , Li Yang , Wenxiu Liu , Tian Cao , Mingdi Yang , Daosheng Sun","doi":"10.1016/j.polymdegradstab.2025.111877","DOIUrl":"10.1016/j.polymdegradstab.2025.111877","url":null,"abstract":"<div><div>Developing high-performance composites for maglev train cables that combine excellent flame retardancy, mechanical properties and fatigue resistance is currently a significant challenge in special cable industry. Herein, a multifunctional reactive phosphorus nitrogen flame retardants (UPMDM) with flame retardant and filler surface modification functions was synthesized, and it was employed to control the polymer matrix-filler interactions and the microstructure of ethylene-vinyl acetate copolymer (EVA)-based composite during melt blending. Phosphorus-nitrogen composite flame retardant (MH@UPMDM) could be preformed before melt blending or formed in-situ during melt blending by the reaction between the isocyanate group (-NCO) of UPMDM and the hydroxyl group on the surface of magnesium hydroxide (MH), and the effect of processing type (physical blending/chemical grafting/in-situ reaction) on dispersion kinetics of MH in EVA matrix was investigated. The results indicate preformed MH@UPMDM can play a role in rigid crosslinkers to construct organic-inorganic hybrid network, thus effectively control the dispersion kinetics of the fillers and the filler-matrix interaction in the EVA matrix. Compared with EVA/MH composites, the elongation of EVA/MH@UPMDM composites is increased by nearly 2.2-fold, while it also exhibits an excellent fatigue-resistance under 1.0 × 10<sup>4</sup>th cycles. Furthermore, MH@UPMDM can significantly enhance the flame retardant properties of the composites, the limiting oxygen index (LOI) of EVA/MH@UPMDM composite reaches 33.6 %, while its peak heat release rate (PHRR) and total heat release (THR) decreases to 277.82 kW/m<sup>2</sup> and 74.71 MJ/m<sup>2</sup> from 436.66 kW/m<sup>2</sup> and 88.67 MJ/m<sup>2</sup> compared to EVA/MH composites, which may be attributed to the multi-phase synergistic flame retardant mechanism of UPMDM.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111877"},"PeriodicalIF":7.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922114","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}
Pub Date : 2025-12-23DOI: 10.1016/j.polymdegradstab.2025.111876
Jiuke Chen , Sabyasachi Gaan , Manfred Heuberger , Ali Gooneie
Phosphorus-based flame retardants (P-FRs) are widely recognized as effective halogen-free additives for flammable thermoplastics, such as polyethylene terephthalate (PET), offering both strong flame resistance and relatively low toxicity. Due to its broad applications, it is crucial to pin down the degradation behavior of PET in the presence of P-FRs to enhance fire safety and polymer circularity. During conventional mechanical recycling, the underlying chemistry in the PET/P-FR materials may cause adverse reactions, leading to deteriorated mechanical properties of recycled products. This study employed reactive molecular dynamics (ReaxFF-MD) simulations based on reactive force field (ReaxFF) to explore the degradation of the PET containing two model P-FRs, specifically DOPO-PEPA (DP) and Aflammit PCO 900 (AF), at elevated temperatures. The predicted thermal behavior of PET was validated against experimental data, and the degradation mechanisms of PET were scrutinized through the analysis of degradation products, bonding evolution, and extensive trajectory analysis. The theoretically predicted thermal decomposition mechanisms of P-FRs were successfully verified by experiment, which is also consistent with existing research. Compared with DP, the molecule AF shows a retarded decomposition during the heat-up before a rapid fragmentation occurs, which can be attributed to its low-energy chair conformation; DP decomposes earlier due to the weaker CO bond linkage and availability of protons via hydrogen abstraction. Our ReaxFF-MD simulations are based on quantum mechanical calculations and allow for an explicit investigation of the interactions between PET and P-FRs by including polymeric chains and additives in the same simulation. The reactions involving phosphorus species in the PET/P-FR were identified; notably DP fragment that can combine with the polymeric chain-end, as well as gasification effects from AF, which together aids in the comprehensive understanding of their different modes of action. In addition to the temperature effects, the oxidative conditions were included in this study to determine the thermo-oxidative degradation behavior. In this study, ReaxFF-MD simulations provide valuable insights into how thermal and thermo-oxidative degradation pathways evolve and control the fragmentation of PET and PET/P-FR systems. This methodology is proposed as a foundation for future research aimed at understanding complex reaction networks and improving the recycling quality of PET/P-FR materials.
{"title":"When PET meets phosphorus flame retardants: A ReaxFF molecular dynamics study","authors":"Jiuke Chen , Sabyasachi Gaan , Manfred Heuberger , Ali Gooneie","doi":"10.1016/j.polymdegradstab.2025.111876","DOIUrl":"10.1016/j.polymdegradstab.2025.111876","url":null,"abstract":"<div><div>Phosphorus-based flame retardants (P-FRs) are widely recognized as effective halogen-free additives for flammable thermoplastics, such as polyethylene terephthalate (PET), offering both strong flame resistance and relatively low toxicity. Due to its broad applications, it is crucial to pin down the degradation behavior of PET in the presence of P-FRs to enhance fire safety and polymer circularity. During conventional mechanical recycling, the underlying chemistry in the PET/P-FR materials may cause adverse reactions, leading to deteriorated mechanical properties of recycled products. This study employed reactive molecular dynamics (ReaxFF-MD) simulations based on reactive force field (ReaxFF) to explore the degradation of the PET containing two model P-FRs, specifically DOPO-PEPA (DP) and Aflammit PCO 900 (AF), at elevated temperatures. The predicted thermal behavior of PET was validated against experimental data, and the degradation mechanisms of PET were scrutinized through the analysis of degradation products, bonding evolution, and extensive trajectory analysis. The theoretically predicted thermal decomposition mechanisms of P-FRs were successfully verified by experiment, which is also consistent with existing research. Compared with DP, the molecule AF shows a retarded decomposition during the heat-up before a rapid fragmentation occurs, which can be attributed to its low-energy chair conformation; DP decomposes earlier due to the weaker C<img>O bond linkage and availability of protons via hydrogen abstraction. Our ReaxFF-MD simulations are based on quantum mechanical calculations and allow for an explicit investigation of the interactions between PET and P-FRs by including polymeric chains and additives in the same simulation. The reactions involving phosphorus species in the PET/P-FR were identified; notably DP fragment that can combine with the polymeric chain-end, as well as gasification effects from AF, which together aids in the comprehensive understanding of their different modes of action. In addition to the temperature effects, the oxidative conditions were included in this study to determine the thermo-oxidative degradation behavior. In this study, ReaxFF-MD simulations provide valuable insights into how thermal and thermo-oxidative degradation pathways evolve and control the fragmentation of PET and PET/P-FR systems. This methodology is proposed as a foundation for future research aimed at understanding complex reaction networks and improving the recycling quality of PET/P-FR materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111876"},"PeriodicalIF":7.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881259","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}
Pub Date : 2025-12-23DOI: 10.1016/j.polymdegradstab.2025.111878
Ruiqi Shao , Youxiang Qiu , Gaohui Wang , Tianshuai Ma , Nishonov Akbarjon , Tianyu Li , Amna Siddique , Shouguo Liu , Xiaoyuan Pei , Zhiwei Xu
Polyacrylonitrile (PAN)-based carbon fibers exhibit mechanical properties affected by structural evolution of microfibrils during pre-oxidation. Irradiation can effectively regulate microstructure and enhance the pre-oxidation effect of fibers. To precisely evaluate the effect of irradiation dose on microfibrils, synchrotron-based ultra-small-angle X-ray scattering (USAXS), in combination with small angle X-ray scattering and wide angle X-ray scattering, was employed. Results reveal that γ-irradiation induces dose-dependent structural modifications in the microfibril network, which is governed by the evolution of microporous structures and crystalline order in PAN fibers. At low-dose irradiation (≤100 kGy), cross-linking dominates, resulting in pore compression, improved orientation angle of microfibrils (from 7.26 to 6.21°).
In contrast, high doses (≥200 kGy) lead to chain scission, pore coarsening, and loss of microfibrils orientation. During irradiation fiber heat treatment, microfibrils evolution occurs in three stages and is regulated by irradiation dose. Initially (180–220 °C), ordering of segments in the amorphous region causes an increase in microfibrils dimensions while maintaining high orientation. Low-dose irradiation provides support through crosslinking, whereas high doses weaken stability due to chain breakage. Intermediately (220–250 °C), cyclization reactions disrupt crystalline regions, causing microfibrils breakage and orientation disorder. The crosslinked network from low-dose irradiation suppresses chain slip and mitigates damage. In contrast, high doses amplify defects and exacerbate disruption. Finally (250–280 °C), trapezoidal structures are formed, driving lateral compression and axial rearrangement of microfibrils. Low-dose irradiation promotes ordered densification; high doses cause disorder and loosening. An optimal dose of 100 kGy concurrently optimizes microfibrillar and microporous morphology, enhancing thermal stability and carbon yield.
{"title":"Radiation-thermal coupling-driven dynamic restructuring of PAN microfibril: dose-response mechanism of γ-irradiation pre-oxidation revealed by synchrotron radiation USAXS","authors":"Ruiqi Shao , Youxiang Qiu , Gaohui Wang , Tianshuai Ma , Nishonov Akbarjon , Tianyu Li , Amna Siddique , Shouguo Liu , Xiaoyuan Pei , Zhiwei Xu","doi":"10.1016/j.polymdegradstab.2025.111878","DOIUrl":"10.1016/j.polymdegradstab.2025.111878","url":null,"abstract":"<div><div>Polyacrylonitrile (PAN)-based carbon fibers exhibit mechanical properties affected by structural evolution of microfibrils during pre-oxidation. Irradiation can effectively regulate microstructure and enhance the pre-oxidation effect of fibers. To precisely evaluate the effect of irradiation dose on microfibrils, synchrotron-based ultra-small-angle X-ray scattering (USAXS), in combination with small angle X-ray scattering and wide angle X-ray scattering, was employed. Results reveal that γ-irradiation induces dose-dependent structural modifications in the microfibril network, which is governed by the evolution of microporous structures and crystalline order in PAN fibers. At low-dose irradiation (≤100 kGy), cross-linking dominates, resulting in pore compression, improved orientation angle of microfibrils (from 7.26 to 6.21°).</div><div>In contrast, high doses (≥200 kGy) lead to chain scission, pore coarsening, and loss of microfibrils orientation. During irradiation fiber heat treatment, microfibrils evolution occurs in three stages and is regulated by irradiation dose. Initially (180–220 °C), ordering of segments in the amorphous region causes an increase in microfibrils dimensions while maintaining high orientation. Low-dose irradiation provides support through crosslinking, whereas high doses weaken stability due to chain breakage. Intermediately (220–250 °C), cyclization reactions disrupt crystalline regions, causing microfibrils breakage and orientation disorder. The crosslinked network from low-dose irradiation suppresses chain slip and mitigates damage. In contrast, high doses amplify defects and exacerbate disruption. Finally (250–280 °C), trapezoidal structures are formed, driving lateral compression and axial rearrangement of microfibrils. Low-dose irradiation promotes ordered densification; high doses cause disorder and loosening. An optimal dose of 100 kGy concurrently optimizes microfibrillar and microporous morphology, enhancing thermal stability and carbon yield.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111878"},"PeriodicalIF":7.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881198","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}
Pub Date : 2025-12-23DOI: 10.1016/j.polymdegradstab.2025.111879
Xingda Li , Keyun Tao , Jiangmeng Song , Jinliang He , Shangshi Huang , Guochang Li , Yanhui Wei
The semi-conductive shielding layer is the important component of high-voltage cables, mainly composed of the polymer matrix and conductive carbon black(CB). In this paper, the aging characteristics of propylene-ethylene copolymer(POP)-toughening polypropylene(PP) semi-conductive composite materials is investigated. Furtherly, a novel aging status identification method based on the fluorescent probe is explored. Firstly, the shielding layer shows a shrinkage phenomenon suffering a long time for thermo-oxidative aging, that is, obvious gaps appear between the base resins. Meanwhile, the surface roughness reaches 32.1 nm, which is 300% of the unaged shielding layer. However, the shielding layer is injected more space charges into the insulation layer after 60 days of aging, reaching 0.710 × 10–7C, which is 50% higher than that of the unaged sample. Additionally, the elongation at break of the sample aged for 60 days decreases sharply to only 102%. Based on the above results, the chain initiation, chain growth and chain termination during the thermo-oxidative aging process of the shielding layer are analyzed, and the changes in oxygen-containing functional groups such as hydroxyl and carbonyl caused by aging are obtained. The fluorescent probes and confocal laser scanning microscopy(CLSM) are employed to track and localize hydroxyl groups in the shielding layer, achieving visualization of the aging process. Furthermore, by using the CLSM to conduct two-dimensional and three-dimensional imaging of the samples, the aging development process of the semi-conductive shielding layer is analyzed both in the plane and in the space. This work holds significant importance for the development and application of PP insulation cables.
{"title":"Aging Characteristics of Semi-conductive Shielding Layer used for Polypropylene Insulation Cable and A Novel Aging State Evaluation Method Based on Fluorescent Probes","authors":"Xingda Li , Keyun Tao , Jiangmeng Song , Jinliang He , Shangshi Huang , Guochang Li , Yanhui Wei","doi":"10.1016/j.polymdegradstab.2025.111879","DOIUrl":"10.1016/j.polymdegradstab.2025.111879","url":null,"abstract":"<div><div>The semi-conductive shielding layer is the important component of high-voltage cables, mainly composed of the polymer matrix and conductive carbon black(CB). In this paper, the aging characteristics of propylene-ethylene copolymer(POP)-toughening polypropylene(PP) semi-conductive composite materials is investigated. Furtherly, a novel aging status identification method based on the fluorescent probe is explored. Firstly, the shielding layer shows a shrinkage phenomenon suffering a long time for thermo-oxidative aging, that is, obvious gaps appear between the base resins. Meanwhile, the surface roughness reaches 32.1 nm, which is 300% of the unaged shielding layer. However, the shielding layer is injected more space charges into the insulation layer after 60 days of aging, reaching 0.710 × 10<sup>–7</sup>C, which is 50% higher than that of the unaged sample. Additionally, the elongation at break of the sample aged for 60 days decreases sharply to only 102%. Based on the above results, the chain initiation, chain growth and chain termination during the thermo-oxidative aging process of the shielding layer are analyzed, and the changes in oxygen-containing functional groups such as hydroxyl and carbonyl caused by aging are obtained. The fluorescent probes and confocal laser scanning microscopy(CLSM) are employed to track and localize hydroxyl groups in the shielding layer, achieving visualization of the aging process. Furthermore, by using the CLSM to conduct two-dimensional and three-dimensional imaging of the samples, the aging development process of the semi-conductive shielding layer is analyzed both in the plane and in the space. This work holds significant importance for the development and application of PP insulation cables.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111879"},"PeriodicalIF":7.4,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145881167","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}
Pub Date : 2025-12-22DOI: 10.1016/j.polymdegradstab.2025.111875
Jiale Song , Xiangrong Chen , Zhuohan Li , Xiaohe Chen , Ashish Paramane
As a key insulating medium in dry direct-current (DC) capacitors, biaxially oriented polypropylene (BOPP) film undergoes performance degradation under the long-term electro-thermal-mechanical multi-physics field, leading to failure of capacitor. To investigate the degradation mechanism of BOPP film’s insulation properties under long-term multi-physics field stress, a multi-stress aging platform and thermal pulse method (TPM) space charge testing platform were developed indigenously. The physicochemical properties, electrical properties, and space charge characteristics of 5.8 μm thick BOPP films were examined after aging at 150 kV/mm, 80 °C, and 10 N for 0 h, 168 h, 360 h, and 720 h. The results indicate that under prolonged multi-stress aging conditions, polypropylene molecular chains undergo scission, generating low molecular weight products. The size of surface defects, surface roughness, degree of crystallinity, and lamellar thickness gradually increased. The breakdown strength and inception voltage of internal discharge in the film decreased, whereas the discharge repetition rate increased. Successive injection of both positive and negative charges was observed within the films during the aging. The findings demonstrate that the breakdown performance is closely related to changes in charge injection and the internal structure of polypropylene. Increased space charge injection at the nanoscale leads to greater defect sizes and trap densities at the microscale, resulting in electric field distortion that frequently triggers the partial discharges and reduces breakdown strength at the macroscale.
{"title":"Effect of long-term electro-thermal-mechanical stresses on insulation degradation of biaxially oriented polypropylene films for dry direct-current capacitors application","authors":"Jiale Song , Xiangrong Chen , Zhuohan Li , Xiaohe Chen , Ashish Paramane","doi":"10.1016/j.polymdegradstab.2025.111875","DOIUrl":"10.1016/j.polymdegradstab.2025.111875","url":null,"abstract":"<div><div>As a key insulating medium in dry direct-current (DC) capacitors, biaxially oriented polypropylene (BOPP) film undergoes performance degradation under the long-term electro-thermal-mechanical multi-physics field, leading to failure of capacitor. To investigate the degradation mechanism of BOPP film’s insulation properties under long-term multi-physics field stress, a multi-stress aging platform and thermal pulse method (TPM) space charge testing platform were developed indigenously. The physicochemical properties, electrical properties, and space charge characteristics of 5.8 μm thick BOPP films were examined after aging at 150 kV/mm, 80 °C, and 10 N for 0 h, 168 h, 360 h, and 720 h. The results indicate that under prolonged multi-stress aging conditions, polypropylene molecular chains undergo scission, generating low molecular weight products. The size of surface defects, surface roughness, degree of crystallinity, and lamellar thickness gradually increased. The breakdown strength and inception voltage of internal discharge in the film decreased, whereas the discharge repetition rate increased. Successive injection of both positive and negative charges was observed within the films during the aging. The findings demonstrate that the breakdown performance is closely related to changes in charge injection and the internal structure of polypropylene. Increased space charge injection at the nanoscale leads to greater defect sizes and trap densities at the microscale, resulting in electric field distortion that frequently triggers the partial discharges and reduces breakdown strength at the macroscale.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111875"},"PeriodicalIF":7.4,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838552","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}
Pub Date : 2025-12-19DOI: 10.1016/j.polymdegradstab.2025.111874
Carla I. La Fuente Arias, Chelo González-Martínez, Amparo Chiralt
Biodegradation of bioplastics in marine ecosystems is affected by biotic and abiotic factors related to the marine zone and the material composition. In this study, the biodegradation and disintegration behavior of PHBV films containing or not containing catechin and cellulose fibers was studied in a simulated Sublittoral zone at laboratory scale. The films were produced by melt blending and compression molding. Biodegradation rate was monitored through the respirometric method, according to the standard ISO 19,679:2020. Disintegration rate (mass loss) of the samples was also analyzed at different exposure times, while the changes in microstructure and thermal behavior of the residual film were characterized. Likewise, the influence of the antimicrobial (catechin) on the bacterial biofilm and taxonomic profiles after 200 exposure days was studied by DNA extraction and the analysis by Amplicon Sequencing. Cellulose fibers slightly accelerated the films' biodegradation by promoting bulk hydrolysis in the matrix due to their hydrophilic nature. In contrast, Catechin delayed the biodegradation and disintegration of PHBV films, which was attributed to its crosslinking effect in the polymer amorphous phase and its influence on the biofilm bacterial population, which could reduce the predominance of enzyme-producing bacteria responsible for film depolymerization.
{"title":"Biodegradation of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in simulated sublittoral marine environment, as affected by reinforcing and antimicrobial agents","authors":"Carla I. La Fuente Arias, Chelo González-Martínez, Amparo Chiralt","doi":"10.1016/j.polymdegradstab.2025.111874","DOIUrl":"10.1016/j.polymdegradstab.2025.111874","url":null,"abstract":"<div><div>Biodegradation of bioplastics in marine ecosystems is affected by biotic and abiotic factors related to the marine zone and the material composition. In this study, the biodegradation and disintegration behavior of PHBV films containing or not containing catechin and cellulose fibers was studied in a simulated Sublittoral zone at laboratory scale. The films were produced by melt blending and compression molding. Biodegradation rate was monitored through the respirometric method, according to the standard ISO 19,679:2020. Disintegration rate (mass loss) of the samples was also analyzed at different exposure times, while the changes in microstructure and thermal behavior of the residual film were characterized. Likewise, the influence of the antimicrobial (catechin) on the bacterial biofilm and taxonomic profiles after 200 exposure days was studied by DNA extraction and the analysis by Amplicon Sequencing. Cellulose fibers slightly accelerated the films' biodegradation by promoting bulk hydrolysis in the matrix due to their hydrophilic nature. In contrast, Catechin delayed the biodegradation and disintegration of PHBV films, which was attributed to its crosslinking effect in the polymer amorphous phase and its influence on the biofilm bacterial population, which could reduce the predominance of enzyme-producing bacteria responsible for film depolymerization.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111874"},"PeriodicalIF":7.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838548","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}
Pub Date : 2025-12-18DOI: 10.1016/j.polymdegradstab.2025.111872
Shuangjiang He , Zhong Zeng , Wenbin Chen , Xiao Xiao , Ning An , Youquan Ling , Shuai Li , Long Ni , Xiaowen Zhao , Mei Liang , Yang Chen , Huawei Zou
To address the challenges encountered by conventional antioxidants, such as migration, toxicity, and single aging resistance mechanisms, which fail to meet the demands for high performance and sustainability. In this study, a series of multi-mechanistic bio-based antioxidants (PDTA-RE) featuring polyphenol-thiourea-rare earth synergy were designed through a sequential “polymerization-grafting-complexation” strategy. Then, the thermo-oxidative aging resistance of composites was evaluated via 121 °C accelerated aging tests, thermal analysis, and kinetic analysis of thermal-oxidative decomposition. Following 120 h of aging, the PDTASc/NBR composites exhibited a tensile strength retention rate of 93.63% and an aging coefficient (K) of 0.61, which were 79.85% and 258.82% higher than those of Neat/NBR, respectively, while superior to commercial antioxidants. Moreover, polyphenolic groups scavenge free radicals, thiourea mercapto decompose hydroperoxides, and rare earth ions trap residual radicals. Additionally, the polymerized framework and double bond anchoring endowed PDTA-RE with excellent anti-migration ability, avoiding high-temperature efficacy loss.
{"title":"Multi-mechanistic bio-based antioxidants constructed by polyphenol-thiourea-rare earth synergy on enhancing thermo-oxidative aging resistance of NBR","authors":"Shuangjiang He , Zhong Zeng , Wenbin Chen , Xiao Xiao , Ning An , Youquan Ling , Shuai Li , Long Ni , Xiaowen Zhao , Mei Liang , Yang Chen , Huawei Zou","doi":"10.1016/j.polymdegradstab.2025.111872","DOIUrl":"10.1016/j.polymdegradstab.2025.111872","url":null,"abstract":"<div><div>To address the challenges encountered by conventional antioxidants, such as migration, toxicity, and single aging resistance mechanisms, which fail to meet the demands for high performance and sustainability. In this study, a series of multi-mechanistic bio-based antioxidants (PDTA-RE) featuring polyphenol-thiourea-rare earth synergy were designed through a sequential “polymerization-grafting-complexation” strategy. Then, the thermo-oxidative aging resistance of composites was evaluated via 121 °C accelerated aging tests, thermal analysis, and kinetic analysis of thermal-oxidative decomposition. Following 120 h of aging, the PDTASc/NBR composites exhibited a tensile strength retention rate of 93.63% and an aging coefficient (<em>K</em>) of 0.61, which were 79.85% and 258.82% higher than those of Neat/NBR, respectively, while superior to commercial antioxidants. Moreover, polyphenolic groups scavenge free radicals, thiourea mercapto decompose hydroperoxides, and rare earth ions trap residual radicals. Additionally, the polymerized framework and double bond anchoring endowed PDTA-RE with excellent anti-migration ability, avoiding high-temperature efficacy loss.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111872"},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838550","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}
Pub Date : 2025-12-18DOI: 10.1016/j.polymdegradstab.2025.111873
Alulutho Ngonyamana , Bothwell Nyoni , Jabulani I. Mnyango , Invine T. Kandirai , Shanganyane P. Hlangothi , Sudhakar Muniyasamy
In the framework of a circular economy, bioplastics derived from renewable natural resources are gaining attention as sustainable alternatives to conventional plastics. This study reports the synthesis of bioplastic films from brown seaweed (Sargassum oligocystum) and red seaweed (Eucheuma spinosum) via alginate extraction, followed by structural and thermal characterization. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry results confirmed that Sargassum oligocystum-based bioplastic exhibited properties comparable to the commercial sodium alginate-derived bioplastic. Additionally, thermogravimetric analysis results revealed that Sargassum oligocystum decomposed in a single step near 220 °C, whereas Eucheuma spinosum degraded in two steps at 280 °C and 330 °C. The corresponding bioplastic films showed decomposition at 225 °C (Sargassum oligocystum) and 250 °C (Eucheuma spinosum). Kinetic studies indicated nucleation-controlled thermal degradation, with activation energies of 20.0 to 26.8 kJ/mol for Eucheuma spinosum and 43.8 to 49.5 kJ/mol for Sargassum oligocystum bioplastics. These findings demonstrate the potential of seaweed-derived bioplastics as renewable, thermally stable materials and provide insights into their degradation mechanisms for future material optimization and practical applications.
{"title":"Bioplastic films from Sargassum oligocystum and Eucheuma spinosum seaweeds: Preparation, thermal degradation, and kinetics analysis","authors":"Alulutho Ngonyamana , Bothwell Nyoni , Jabulani I. Mnyango , Invine T. Kandirai , Shanganyane P. Hlangothi , Sudhakar Muniyasamy","doi":"10.1016/j.polymdegradstab.2025.111873","DOIUrl":"10.1016/j.polymdegradstab.2025.111873","url":null,"abstract":"<div><div>In the framework of a circular economy, bioplastics derived from renewable natural resources are gaining attention as sustainable alternatives to conventional plastics. This study reports the synthesis of bioplastic films from brown seaweed (<em>Sargassum oligocystum</em>) and red seaweed (<em>Eucheuma spinosum</em>) <em>via</em> alginate extraction, followed by structural and thermal characterization. Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry results confirmed that <em>Sargassum oligocystum</em>-based bioplastic exhibited properties comparable to the commercial sodium alginate-derived bioplastic. Additionally, thermogravimetric analysis results revealed that <em>Sargassum oligocystum</em> decomposed in a single step near 220 °C, whereas <em>Eucheuma spinosum</em> degraded in two steps at <span><math><mo>≈</mo></math></span> 280 °C and 330 °C. The corresponding bioplastic films showed decomposition at <span><math><mo>≈</mo></math></span> 225 °C (<em>Sargassum oligocystum</em>) and 250 °C (<em>Eucheuma spinosum</em>). Kinetic studies indicated nucleation-controlled thermal degradation, with activation energies of 20.0 to 26.8 kJ/mol for <em>Eucheuma spinosum</em> and 43.8 to 49.5 kJ/mol for <em>Sargassum oligocystum</em> bioplastics. These findings demonstrate the potential of seaweed-derived bioplastics as renewable, thermally stable materials and provide insights into their degradation mechanisms for future material optimization and practical applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111873"},"PeriodicalIF":7.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838547","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}
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