Pub Date : 2025-12-13DOI: 10.1016/j.polymdegradstab.2025.111860
Xingyao Li, Kangcheng Xu, Lin Wang, Yulu Zhang, Zhishuai Geng, Xangmei Li, Jiyu He, Rongjie Yang
The flammability of polymers limits their use, and traditional flame-retardant approaches no longer meet modern performance needs. To address issues with metal-based flame retardants—such as poor char-forming efficiency and mismatched decomposition—we designed a metal–ligand coordination system that mimics enzymatic catalysis to regulate polyurethane degradation. Under heat, the metal centers selectively cleave weak bonds, suppressing flammable small-molecule formation and promoting the generation of high-molecular-weight, carbon-rich intermediates. These intermediates rapidly crosslink and carbonize, forming a dense char layer that shifts degradation from gasification to carbonization. As a result, (Co-ATMP)₁-co-PU reduces HRR by 69.9%, SPR by 33%, and CO₂ release by 73.4%, while increasing char yield. This catalytic strategy significantly enhances flame retardancy and improves char stability at high temperature, offering a promising route to intrinsically flame-retardant polymers.
{"title":"Inspired by the catalytic properties of biological enzymes: Design of bifunctional catalytic flame retardants for enhanced polyurethane flame retardancy","authors":"Xingyao Li, Kangcheng Xu, Lin Wang, Yulu Zhang, Zhishuai Geng, Xangmei Li, Jiyu He, Rongjie Yang","doi":"10.1016/j.polymdegradstab.2025.111860","DOIUrl":"10.1016/j.polymdegradstab.2025.111860","url":null,"abstract":"<div><div>The flammability of polymers limits their use, and traditional flame-retardant approaches no longer meet modern performance needs. To address issues with metal-based flame retardants—such as poor char-forming efficiency and mismatched decomposition—we designed a metal–ligand coordination system that mimics enzymatic catalysis to regulate polyurethane degradation. Under heat, the metal centers selectively cleave weak bonds, suppressing flammable small-molecule formation and promoting the generation of high-molecular-weight, carbon-rich intermediates. These intermediates rapidly crosslink and carbonize, forming a dense char layer that shifts degradation from gasification to carbonization. As a result, (Co-ATMP)₁-co-PU reduces HRR by 69.9%, SPR by 33%, and CO₂ release by 73.4%, while increasing char yield. This catalytic strategy significantly enhances flame retardancy and improves char stability at high temperature, offering a promising route to intrinsically flame-retardant polymers.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111860"},"PeriodicalIF":7.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789250","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 : 2025-12-11DOI: 10.1016/j.polymdegradstab.2025.111859
Peiyong Ren , Xiaori Yang , Ziyu Wang , Jinwei Yang , Xiaoping Gao , Xin Jiang
With the rapid development of communication technologies, the demand for multifunctional textiles with both electromagnetic interference (EMI) shielding and flame retardancy has intensified. In this study, a graphene-based composite aerogel doped with NiZnFe2O4@MnO2 core-shell microspheres (NiZnFe2O4@MnO2/GA) was synthesized via hydrothermal reduction and subsequently integrated with ammonium polyphosphate (APP) into a waterborne polyurethane (WPU) matrix, which was coated onto aramid/stainless-steel textiles to produce a multifunctional fabric. Interfacial bonding was strengthened through chemical crosslinking, providing a structural basis for the integrated electromagnetic and thermal functions. The EMI shielding and flame-retardant performances of the coated fabrics were systematically evaluated to clarify their synergistic enhancement mechanisms. The three-dimensional (3D) conductive-magnetic network of the NiZnFe2O4@MnO2/GA heterostructure induced strong interfacial polarization losses, achieving a total shielding effectiveness (SET) of 44.5 dB at only 2 wt% loading with a 77 % absorption contribution. Meanwhile, the synergy between NiZnFe2O4@MnO2/GA and APP produced a dual flame-retardant mechanism by stabilizing the char layer and diluting flammable gases. The peak heat release rate (pHRR), total heat release (THR), total smoke production (TSP), and peak CO production (pCO) were reduced by 45.9 %, 53.9 %, 48.1 %, and 85.2 %, respectively, compared with pure WPU-coated fabrics. These findings provide a viable strategy for designing lightweight, flexible fabrics with integrated electromagnetic and thermal protection.
{"title":"Integrated electromagnetic shielding and flame retardancy in coated fabrics through synergistic NiZnFe2O4@MnO2/graphene aerogel and APP","authors":"Peiyong Ren , Xiaori Yang , Ziyu Wang , Jinwei Yang , Xiaoping Gao , Xin Jiang","doi":"10.1016/j.polymdegradstab.2025.111859","DOIUrl":"10.1016/j.polymdegradstab.2025.111859","url":null,"abstract":"<div><div>With the rapid development of communication technologies, the demand for multifunctional textiles with both electromagnetic interference (EMI) shielding and flame retardancy has intensified. In this study, a graphene-based composite aerogel doped with NiZnFe<sub>2</sub>O<sub>4</sub>@MnO<sub>2</sub> core-shell microspheres (NiZnFe<sub>2</sub>O<sub>4</sub>@MnO<sub>2</sub>/GA) was synthesized via hydrothermal reduction and subsequently integrated with ammonium polyphosphate (APP) into a waterborne polyurethane (WPU) matrix, which was coated onto aramid/stainless-steel textiles to produce a multifunctional fabric. Interfacial bonding was strengthened through chemical crosslinking, providing a structural basis for the integrated electromagnetic and thermal functions. The EMI shielding and flame-retardant performances of the coated fabrics were systematically evaluated to clarify their synergistic enhancement mechanisms. The three-dimensional (3D) conductive-magnetic network of the NiZnFe<sub>2</sub>O<sub>4</sub>@MnO<sub>2</sub>/GA heterostructure induced strong interfacial polarization losses, achieving a total shielding effectiveness (SE<sub>T</sub>) of 44.5 dB at only 2 wt% loading with a 77 % absorption contribution. Meanwhile, the synergy between NiZnFe<sub>2</sub>O<sub>4</sub>@MnO<sub>2</sub>/GA and APP produced a dual flame-retardant mechanism by stabilizing the char layer and diluting flammable gases. The peak heat release rate (pHRR), total heat release (THR), total smoke production (TSP), and peak CO production (pCO) were reduced by 45.9 %, 53.9 %, 48.1 %, and 85.2 %, respectively, compared with pure WPU-coated fabrics. These findings provide a viable strategy for designing lightweight, flexible fabrics with integrated electromagnetic and thermal protection.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111859"},"PeriodicalIF":7.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760746","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 : 2025-12-11DOI: 10.1016/j.polymdegradstab.2025.111858
Kata Enikő Decsov , Emese Győry-Slezák , Dániel Gere , Ferenc Ronkay , Béla Botond Marosfői , Sándor Lenk , Katalin Bocz
This study evaluates flame retardant formulations in recycled poly(ethylene terephthalate) (rPET) foams, focusing on processability, performance, and structure-property relationships. Microcellular foams were produced from post-industrial rPET using a CO₂-assisted batch foaming process, incorporating aluminium-tris-(diethylphosphinate) (AlPi), melamine polyphosphate (MPP), and their combination at 5 wt% loading. Morphological, thermal, flammability, mechanical, and optical properties were comprehensively assessed.
The CO₂-assisted process enabled the preparation of highly porous foams (void fraction >70 %) with fine cellular structures (average cell size ∼ 2 µm). AlPi showed superior flame retardant performance, achieving a limiting oxygen index (LOI) of 25.0 %, delayed ignition, and a 23 % reduction in peak heat release rate during cone calorimetry. Enhanced char formation containing thermally stable aluminium phosphates was confirmed via energy dispersive spectroscopy (EDS) and attenuated total reflectance infrared spectroscopy (ATR-IR) analyses. In contrast, MPP alone provided limited flame retardancy, and its combination with AlPi offered no synergistic benefit.
Mechanical performance was primarily determined by foam density, with negligible influence of flame retardant additives. The foams exhibited high crystallinity (χ > 31 %) due to strain-induced crystallisation during cell growth, contributing to enhanced thermomechanical stability. Additionally, the microcellular structure enabled excellent optical reflectivity (>90 %) in the visible spectrum, which was retained even in flame-retarded formulations.
{"title":"Flame retarded recycled PET foams: Comparative analysis of gas-phase and solid-phase additive performance and feasibility","authors":"Kata Enikő Decsov , Emese Győry-Slezák , Dániel Gere , Ferenc Ronkay , Béla Botond Marosfői , Sándor Lenk , Katalin Bocz","doi":"10.1016/j.polymdegradstab.2025.111858","DOIUrl":"10.1016/j.polymdegradstab.2025.111858","url":null,"abstract":"<div><div>This study evaluates flame retardant formulations in recycled poly(ethylene terephthalate) (rPET) foams, focusing on processability, performance, and structure-property relationships. Microcellular foams were produced from post-industrial rPET using a CO₂-assisted batch foaming process, incorporating aluminium-tris-(diethylphosphinate) (AlPi), melamine polyphosphate (MPP), and their combination at 5 wt% loading. Morphological, thermal, flammability, mechanical, and optical properties were comprehensively assessed.</div><div>The CO₂-assisted process enabled the preparation of highly porous foams (void fraction >70 %) with fine cellular structures (average cell size ∼ 2 µm). AlPi showed superior flame retardant performance, achieving a limiting oxygen index (LOI) of 25.0 %, delayed ignition, and a 23 % reduction in peak heat release rate during cone calorimetry. Enhanced char formation containing thermally stable aluminium phosphates was confirmed via energy dispersive spectroscopy (EDS) and attenuated total reflectance infrared spectroscopy (ATR-IR) analyses. In contrast, MPP alone provided limited flame retardancy, and its combination with AlPi offered no synergistic benefit.</div><div>Mechanical performance was primarily determined by foam density, with negligible influence of flame retardant additives. The foams exhibited high crystallinity (χ > 31 %) due to strain-induced crystallisation during cell growth, contributing to enhanced thermomechanical stability. Additionally, the microcellular structure enabled excellent optical reflectivity (>90 %) in the visible spectrum, which was retained even in flame-retarded formulations.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111858"},"PeriodicalIF":7.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760747","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 : 2025-12-11DOI: 10.1016/j.polymdegradstab.2025.111856
Jia-Xiang Yang, Ying-Jun Xu, Ya-Wei Zheng, Wan-Meng Song, Yun Liu
Ramie fiber-reinforced epoxy composites have high mechanical strength and outstanding corrosion resistance, and are widely used in many fields. However, ramie fiber and epoxy resin are inherently flammable, and there is an increasing focus on the flame-retardant improvement of Ramie fiber-reinforced epoxy (EP/RF) composites. In this study, an eco-friendly and higher efficient P-N-B flame retardant (denoted as DBC) was synthesized and subsequently applied to ramie fabric to impart flame retardancy of EP/RF composites. When the weight gain on ramie fabric was about 10 wt%, the limiting oxygen index of EP/RF-DBC is 32.6 %, and EP/RF-DBC has been upgraded from UL-94 No rating to UL-94 V-0 rating. Compared with EP/RF, the peak heat release rate and total heat release of EP/RF-DBC reduced by 31.9 % and 32.0 %, respectively, indicating that the introduction of DBC reduces the fire hazard of EP/RF. The presence of DBC promotes the dehydration of EP/RF into residual chars, which act as a barrier to block the exchange of heat and gas, releasing more noncombustible gases and diluting the concentration of combustible gases. In terms of mechanical properties, due to the low acidity of DBC and the presence of many amino groups in chitosan oligosaccharide, the adhesion between RF and EP is improved. The flexural strength and modulus of EP/RF-DBC are increased by 15.3 % and 32.1 %, respectively, compared with EP/RF.
{"title":"A P-N-B flame retardant synergistically improving fire safety and mechanical properties of ramie fabric/epoxy composites","authors":"Jia-Xiang Yang, Ying-Jun Xu, Ya-Wei Zheng, Wan-Meng Song, Yun Liu","doi":"10.1016/j.polymdegradstab.2025.111856","DOIUrl":"10.1016/j.polymdegradstab.2025.111856","url":null,"abstract":"<div><div>Ramie fiber-reinforced epoxy composites have high mechanical strength and outstanding corrosion resistance, and are widely used in many fields. However, ramie fiber and epoxy resin are inherently flammable, and there is an increasing focus on the flame-retardant improvement of Ramie fiber-reinforced epoxy (EP/RF) composites. In this study, an eco-friendly and higher efficient P-N-B flame retardant (denoted as DBC) was synthesized and subsequently applied to ramie fabric to impart flame retardancy of EP/RF composites. When the weight gain on ramie fabric was about 10 wt%, the limiting oxygen index of EP/RF-DBC is 32.6 %, and EP/RF-DBC has been upgraded from UL-94 No rating to UL-94 V-0 rating. Compared with EP/RF, the peak heat release rate and total heat release of EP/RF-DBC reduced by 31.9 % and 32.0 %, respectively, indicating that the introduction of DBC reduces the fire hazard of EP/RF. The presence of DBC promotes the dehydration of EP/RF into residual chars, which act as a barrier to block the exchange of heat and gas, releasing more noncombustible gases and diluting the concentration of combustible gases. In terms of mechanical properties, due to the low acidity of DBC and the presence of many amino groups in chitosan oligosaccharide, the adhesion between RF and EP is improved. The flexural strength and modulus of EP/RF-DBC are increased by 15.3 % and 32.1 %, respectively, compared with EP/RF.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111856"},"PeriodicalIF":7.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145760748","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 : 2025-12-08DOI: 10.1016/j.polymdegradstab.2025.111855
Tian Y. Liu , Wei J. Zhang , Tian C. Shi , Ze Y. Zhang , Zhi C. Zhen , Ping L. Wang , Xiu B. Yang , Dan Huang , Jun H. Ji , Ge X. Wang
Existing biodegradable plastics encounter performance limitations and degrade slowly in natural environments, especially seawater. Incorporating degradation-promoting monomers can accelerate breakdown but often weakens polymer backbone bonds and reduces crystallinity, sacrificing strength. Consequently, materials with both high strength and rapid degradability are currently missing. This study addresses this issue by enhancing intermolecular interactions in polymers to compensate for reduced mechanical strength. First, adipic acid, a long-chain aliphatic monomer, is introduced into non-degradable PET as a molecular chain flexibility regulator. Using fluorescence screening, polyethylene adipate-co-terephthalate (PEAT) with an optimal A/T ratio of 30/70, demonstrating the strongest intermolecular interactions, is selected as the base material. Glycolic (GA) and lactic (LA) acid are then incorporated as easily hydrolysable sites to synthesis PEATG and PEATL copolyesters. Despite being amorphous, these copolyesters maintain high mechanical strength (up to 70 MPa). Hydroxy acid incorporation accelerates hydrolysis, enabling rapid degradation in seawater and compost environments, especially in PEATG copolyesters. For example, after 238 days in seawater, the molecular weight of PEATG120 (69.9 MPa) drops below 103 g mol−1. After 122 days of composting, PEATG80 (58.5 MPa) and PEATL80 (61.3 MPa) achieve mineralization rates of 43.6 % and 19.1 %, respectively. This approach enables high-strength, fast-degrading materials for natural environments.
现有的可生物降解塑料在自然环境特别是海水中存在性能限制和降解缓慢的问题。加入促进降解的单体可以加速分解，但往往会削弱聚合物的主键，降低结晶度，从而牺牲强度。因此，目前缺乏具有高强度和快速降解性的材料。本研究通过增强聚合物中的分子间相互作用来弥补机械强度的降低，从而解决了这一问题。首先，将长链脂肪族单体己二酸作为分子链柔韧性调节剂引入不可降解PET中。通过荧光筛选，选择具有最强分子间相互作用的最佳A/T比为30/70的聚己二甲酸乙二醇酯（PEAT）作为基础材料。然后将乙醇酸（GA）和乳酸（LA）作为易水解位点掺入合成PEATG和PEATL共聚酯。尽管是无定形的，这些共聚酯保持高机械强度（高达70兆帕）。羟基酸的掺入加速了水解，使其能够在海水和堆肥环境中快速降解，特别是在PEATG共聚酯中。例如，在海水中浸泡238天后，PEATG120的分子量（69.9 MPa）降至103 g mol−1以下。经过122 d的堆肥处理，PEATG80 （58.5 MPa）和peat80 （61.3 MPa）的矿化率分别达到43.6%和19.1%。这种方法使高强度、快速降解的材料适用于自然环境。
{"title":"Breaking the strength-degradability trade-off in PET-based copolyesters via enhanced intermolecular interactions and embedding easily hydrolysable sites","authors":"Tian Y. Liu , Wei J. Zhang , Tian C. Shi , Ze Y. Zhang , Zhi C. Zhen , Ping L. Wang , Xiu B. Yang , Dan Huang , Jun H. Ji , Ge X. Wang","doi":"10.1016/j.polymdegradstab.2025.111855","DOIUrl":"10.1016/j.polymdegradstab.2025.111855","url":null,"abstract":"<div><div>Existing biodegradable plastics encounter performance limitations and degrade slowly in natural environments, especially seawater. Incorporating degradation-promoting monomers can accelerate breakdown but often weakens polymer backbone bonds and reduces crystallinity, sacrificing strength. Consequently, materials with both high strength and rapid degradability are currently missing. This study addresses this issue by enhancing intermolecular interactions in polymers to compensate for reduced mechanical strength. First, adipic acid, a long-chain aliphatic monomer, is introduced into non-degradable PET as a molecular chain flexibility regulator. Using fluorescence screening, polyethylene adipate-co-terephthalate (PEAT) with an optimal A/T ratio of 30/70, demonstrating the strongest intermolecular interactions, is selected as the base material. Glycolic (GA) and lactic (LA) acid are then incorporated as easily hydrolysable sites to synthesis PEATG and PEATL copolyesters. Despite being amorphous, these copolyesters maintain high mechanical strength (up to 70 MPa). Hydroxy acid incorporation accelerates hydrolysis, enabling rapid degradation in seawater and compost environments, especially in PEATG copolyesters. For example, after 238 days in seawater, the molecular weight of PEATG120 (69.9 MPa) drops below 10<sup>3</sup> g mol<sup>−1</sup>. After 122 days of composting, PEATG80 (58.5 MPa) and PEATL80 (61.3 MPa) achieve mineralization rates of 43.6 % and 19.1 %, respectively. This approach enables high-strength, fast-degrading materials for natural environments.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111855"},"PeriodicalIF":7.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789188","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}
Poly-(hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fully biobased and biodegradable in various environments aliphatic polyesters, are produced by a wide range of microorganisms and renewable raw materials. The synthesis of PHB with co-polymers poly-(3-hydroxyvalerate) (HV) allows for a decrease of the glass transition and melting temperatures towards a broadened thermal processing window. Mechanical tensile properties monitoring natural ageing behaviour of either melt blending and compression moulding (MB) or solvent casting (SC) formed PHB and PHBV, with variable content of HV molar composition and molecular weight (Mw) films, of both commercial and laboratory grade (produced from sugar-beet pulp (SBP) and simulated SBP hydrosols), revealed some characteristic differences and their dependence on Mw. These macroscopic results were interpreted via Fourier transform infrared spectroscopy/attenuated total reflection (FTIR/ATR), differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The variation of the ratio of absorbance in the crystalline and amorphous characteristic bands laid the basis for the quantitively determination of crystallinity index ratio (CI) dependence on the HV content and Mw, was consistent with the DSC crystallinity degree (Xc(%)). The crystallisation and melting behaviour of the laboratory and commercial PHB(V) grades, as expressed via POM, revealed the secondary crystallisation pattern predecessors. The goal was to associate the characteristics of polyhydroxyalkanoates (PHAs) with their response under industrial processing conditions.
{"title":"Comparative evaluation of bio-based films made of commercial PHB(V) and laboratory PHB(V) polymers produced from sugar beet pulp hydrosol","authors":"Ioanna-Georgia Athanasoulia, Philippos Tserotas, Demetres Briassoulis","doi":"10.1016/j.polymdegradstab.2025.111844","DOIUrl":"10.1016/j.polymdegradstab.2025.111844","url":null,"abstract":"<div><div>Poly-(hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fully biobased and biodegradable in various environments aliphatic polyesters, are produced by a wide range of microorganisms and renewable raw materials. The synthesis of PHB with co-polymers poly-(3-hydroxyvalerate) (HV) allows for a decrease of the glass transition and melting temperatures towards a broadened thermal processing window. Mechanical tensile properties monitoring natural ageing behaviour of either melt blending and compression moulding (MB) or solvent casting (SC) formed PHB and PHBV, with variable content of HV molar composition and molecular weight (Mw) films, of both commercial and laboratory grade (produced from sugar-beet pulp (SBP) and simulated SBP hydrosols), revealed some characteristic differences and their dependence on Mw. These macroscopic results were interpreted via Fourier transform infrared spectroscopy/attenuated total reflection (FTIR/ATR), differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The variation of the ratio of absorbance in the crystalline and amorphous characteristic bands laid the basis for the quantitively determination of crystallinity index ratio (<em>CI</em>) dependence on the HV content and Mw, was consistent with the DSC crystallinity degree (<em>X<sub>c</sub></em>(%)). The crystallisation and melting behaviour of the laboratory and commercial PHB(V) grades, as expressed via POM, revealed the secondary crystallisation pattern predecessors. The goal was to associate the characteristics of polyhydroxyalkanoates (PHAs) with their response under industrial processing conditions.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"244 ","pages":"Article 111844"},"PeriodicalIF":7.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746948","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 : 2025-12-08DOI: 10.1016/j.polymdegradstab.2025.111853
Fan Yang , Xing Li , Pengbo Wang , Yanzhi Wu , Xinheng Li , Yuxin Fang , Shaohua Wang
Understanding the aging mechanisms of polypropylene (PP) cable insulation under thermal and oxidative stress is crucial for ensuring the reliable operation of power systems. Although PP insulation holds promise as an alternative to cross-linked polyethylene (XLPE), its development is still ongoing, and its long-term aging process is not yet fully understood. In this work, the thermo-oxidative aging behavior of PP cable insulation was investigated using terahertz time-domain spectroscopy (THz-TDS). Optical and dielectric responses of the aged materials were extracted from the measured time-domain spectra. The thermal, chemical, and crystallization properties of the samples were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results show a clear decoupling between chemical oxidation and structural changes. The carbonyl index (CI) increased continuously with aging time, while crystallinity first increased and then decreased, reaching a peak at approximately 288 h. This behavior originates from a dynamic competition between recrystallization induced by chain scission and the degradation of existing crystalline regions. Both the real (ε′) and imaginary (ε″) components of the terahertz dielectric response closely followed the changes in crystallinity, rather than the steady increase in CI. A strong linear relationship (R² = 0.85) was established between ε′ and the crystallinity measured by XRD. These results suggest that the terahertz dielectric response of PP-g-MAH during aging is mainly influenced by structural changes rather than changes in chemical polarity. This finding not only provides new insights into the interaction mechanisms between terahertz waves and polymers but also offers a solid theoretical basis for developing non-destructive terahertz methods to assess the insulation performance of polymer materials.
{"title":"Non-destructive evaluation of thermo-oxidative aging in PP-g-MAH cable insulation using terahertz dielectric spectroscopy","authors":"Fan Yang , Xing Li , Pengbo Wang , Yanzhi Wu , Xinheng Li , Yuxin Fang , Shaohua Wang","doi":"10.1016/j.polymdegradstab.2025.111853","DOIUrl":"10.1016/j.polymdegradstab.2025.111853","url":null,"abstract":"<div><div>Understanding the aging mechanisms of polypropylene (PP) cable insulation under thermal and oxidative stress is crucial for ensuring the reliable operation of power systems. Although PP insulation holds promise as an alternative to cross-linked polyethylene (XLPE), its development is still ongoing, and its long-term aging process is not yet fully understood. In this work, the thermo-oxidative aging behavior of PP cable insulation was investigated using terahertz time-domain spectroscopy (THz-TDS). Optical and dielectric responses of the aged materials were extracted from the measured time-domain spectra. The thermal, chemical, and crystallization properties of the samples were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The results show a clear decoupling between chemical oxidation and structural changes. The carbonyl index (CI) increased continuously with aging time, while crystallinity first increased and then decreased, reaching a peak at approximately 288 h. This behavior originates from a dynamic competition between recrystallization induced by chain scission and the degradation of existing crystalline regions. Both the real (ε′) and imaginary (ε″) components of the terahertz dielectric response closely followed the changes in crystallinity, rather than the steady increase in CI. A strong linear relationship (R² = 0.85) was established between ε′ and the crystallinity measured by XRD. These results suggest that the terahertz dielectric response of PP-g-MAH during aging is mainly influenced by structural changes rather than changes in chemical polarity. This finding not only provides new insights into the interaction mechanisms between terahertz waves and polymers but also offers a solid theoretical basis for developing non-destructive terahertz methods to assess the insulation performance of polymer materials.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"244 ","pages":"Article 111853"},"PeriodicalIF":7.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145796674","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 : 2025-12-08DOI: 10.1016/j.polymdegradstab.2025.111852
Miriam Paola Barrera Nava , María Dolores de Dios Caputto , Rodrigo Navarro , Alberto Fernández Torres , Antonio Martínez-Richa , Ángel Marcos-Fernández
This study presents an efficient chemical upcycling route for complex poly(ethylene terephthalate) (PET) waste, including post-consumer bottles, thermoform PET, and the glycolysed monomer bis(2-hydroxyethyl) terephthalate (BHET), transforming them into liquid polyols for the synthesis of polyurethanes. The strategy is based on a catalysed solvolysis using ethylene carbonate (EC) as both a reagent and solvent, operating under mild conditions and at atmospheric pressure. A systematic screening demonstrated that caesium carbonate (Cs2CO3) is more efficient catalyst than KOH, as it minimises the hydrolysis of carbonate groups, thereby yielding polyols with a higher content of these valuable units. Kinetic studies revealed the critical importance of reaction time and the transition from a heterogeneous to a solvated and highly swollen polymer state.
The resulting polyols, with controlled molecular weights in the range of 1000–2500 g/mol —appropriate for use as soft segments— were successfully employed in the synthesis of polyurethanes. The final materials exhibited high molecular weights and thermal properties that correlate with the chemical composition of the precursor polyol, validating this methodology as a versatile and sustainable alternative to advance towards a circular economy.
{"title":"Chemical upcycling of complex PET waste: Upcycling of milder reaction conditions and use for polyurethane as added-value product","authors":"Miriam Paola Barrera Nava , María Dolores de Dios Caputto , Rodrigo Navarro , Alberto Fernández Torres , Antonio Martínez-Richa , Ángel Marcos-Fernández","doi":"10.1016/j.polymdegradstab.2025.111852","DOIUrl":"10.1016/j.polymdegradstab.2025.111852","url":null,"abstract":"<div><div>This study presents an efficient chemical upcycling route for complex poly(ethylene terephthalate) (PET) waste, including post-consumer bottles, thermoform PET, and the glycolysed monomer bis(2-hydroxyethyl) terephthalate (BHET), transforming them into liquid polyols for the synthesis of polyurethanes. The strategy is based on a catalysed solvolysis using ethylene carbonate (EC) as both a reagent and solvent, operating under mild conditions and at atmospheric pressure. A systematic screening demonstrated that caesium carbonate (Cs<sub>2</sub>CO<sub>3</sub>) is more efficient catalyst than KOH, as it minimises the hydrolysis of carbonate groups, thereby yielding polyols with a higher content of these valuable units. Kinetic studies revealed the critical importance of reaction time and the transition from a heterogeneous to a solvated and highly swollen polymer state.</div><div>The resulting polyols, with controlled molecular weights in the range of 1000–2500 g/mol —appropriate for use as soft segments— were successfully employed in the synthesis of polyurethanes. The final materials exhibited high molecular weights and thermal properties that correlate with the chemical composition of the precursor polyol, validating this methodology as a versatile and sustainable alternative to advance towards a circular economy.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"244 ","pages":"Article 111852"},"PeriodicalIF":7.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145748384","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 : 2025-12-07DOI: 10.1016/j.polymdegradstab.2025.111851
A.A. Nabiyev , O.I. Ivankov , A.K. Azhibekov , A.H.A. Elmekawy , E. Popov , S.F. Samadov , N.V.M. Trung , A.K. Mutali , A.A. Sidorin , O.S. Orlov , A.I. Kuklin
This paper presents the findings of a study on the effects of gamma radiation on the structural and thermal characteristics of high-density polyethylene nanocomposite films. These thin films consist of a combination of high-density polyethylene (HDPE) and nano-SiO2 particles prepared by hydrostatic thermal pressing a mixture of HDPE powder and nano-SiO2 in various volume concentrations (ω = 1 %, 5 %, 10 %, and 20 %). Radiation-induced defects and microstructural changes in HDPE nanocomposite films containing embedded nano-SiO2 particles were investigated under high-dose gamma irradiation (100–500 kGy). DBAS analysis revealed that SiO2 nanoparticles effectively suppress radiation-induced defect formation and positronium formation across most doses through void-filling and interfacial positron trapping mechanisms. Defect evolution showed a transition from chain scission-dominated behavior (increasing defects up to 300 kGy) to crosslinking dominance at 500 kGy, with SiO2 significantly mitigating both processes. However, at the critical dose of 300 kGy, where crystallinity (66.2 %) and structural reorganization peak, anomalous defect behavior was observed for 1 % and 20 % SiO2 loadings, attributed to insufficient structural constraint and interfacial stress concentration, respectively. Electron momentum distribution (EMD) analysis confirmed carbonyl group (C = O) formation during oxidative degradation. Optimal radiation resistance was achieved with 5–10 vol% SiO2 at doses up to 300 kGy, consistent with SAXS and WAXS findings.
These results provide fundamental insights into radiation resistance mechanisms and support the design of HDPE/SiO2 nanocomposites for use in high-dose radiation environments.
{"title":"High-dose gamma irradiation effects on HDPE/SiO2 nanocomposite films: Structure, crystallinity, defects, radiation endurance, dispersion, and interfacial behavior","authors":"A.A. Nabiyev , O.I. Ivankov , A.K. Azhibekov , A.H.A. Elmekawy , E. Popov , S.F. Samadov , N.V.M. Trung , A.K. Mutali , A.A. Sidorin , O.S. Orlov , A.I. Kuklin","doi":"10.1016/j.polymdegradstab.2025.111851","DOIUrl":"10.1016/j.polymdegradstab.2025.111851","url":null,"abstract":"<div><div>This paper presents the findings of a study on the effects of gamma radiation on the structural and thermal characteristics of high-density polyethylene nanocomposite films. These thin films consist of a combination of high-density polyethylene (HDPE) and nano-SiO<sub>2</sub> particles prepared by hydrostatic thermal pressing a mixture of HDPE powder and nano-SiO<sub>2</sub> in various volume concentrations (ω = 1 %, 5 %, 10 %, and 20 %). Radiation-induced defects and microstructural changes in HDPE nanocomposite films containing embedded nano-SiO<sub>2</sub> particles were investigated under high-dose gamma irradiation (100–500 kGy). DBAS analysis revealed that SiO<sub>2</sub> nanoparticles effectively suppress radiation-induced defect formation and positronium formation across most doses through void-filling and interfacial positron trapping mechanisms. Defect evolution showed a transition from chain scission-dominated behavior (increasing defects up to 300 kGy) to crosslinking dominance at 500 kGy, with SiO<sub>2</sub> significantly mitigating both processes. However, at the critical dose of 300 kGy, where crystallinity (66.2 %) and structural reorganization peak, anomalous defect behavior was observed for 1 % and 20 % SiO<sub>2</sub> loadings, attributed to insufficient structural constraint and interfacial stress concentration, respectively. Electron momentum distribution (EMD) analysis confirmed carbonyl group (C = O) formation during oxidative degradation. Optimal radiation resistance was achieved with 5–10 vol% SiO<sub>2</sub> at doses up to 300 kGy, consistent with SAXS and WAXS findings.</div><div>These results provide fundamental insights into radiation resistance mechanisms and support the design of HDPE/SiO<sub>2</sub> nanocomposites for use in high-dose radiation environments.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"245 ","pages":"Article 111851"},"PeriodicalIF":7.4,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789183","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 : 2025-12-07DOI: 10.1016/j.polymdegradstab.2025.111845
Cristian–Dragos Varganici , Immacolata Climaco , Liliana Rosu , Dan Rosu , Amedeo Amoresano , Flavia Zuber , Milijana Jovic , Qun Ren , Sabyasachi Gaan , Antonio Aronne , Claudio Imparato , Aurelio Bifulco
Biofouling poses a critical challenge with significant economic consequences, particularly in the naval industry, where it can increase fuel consumption by up to 40 % due to impaired hydrodynamics. With growing environmental regulations limiting the use of toxic biocides and the increasing demand for high-performing next-generation materials, effective multifunctional protective coatings have never been more desirable. Herein, we present a sustainable solution based on antifouling epoxy-based coatings incorporating rosin-modified hybrid TiO₂ particles, synthesized via the sol-gel method and functionalized in situ with hydrophobic alkylsilanes. Our results demonstrate a robust antibacterial and antifungal effect, driven by the formation of charge transfer complexes between rosin (i.e., a biowaste derived from the secretion of pines) and Ti⁴⁺, which generate reactive oxygen species on the coatings’ surface, effectively inhibiting microbial colonization. The addition of alkylsilanes enhances the antifouling performance by promoting the migration of the hybrid fillers to the surface, conferring superior hydrophobicity and hindering fungal adhesion. Crucially, the synergistic presence of silanes and TiO₂ also delivers a remarkable 38 % reduction in the peak of the heat release rate, boosting fire safety without compromising coating integrity. This work highlights an intriguing waste-to-wealth biocide-free strategy for engineering next-generation flame retardant, antimicrobial, and antifouling coatings, offering a scalable and environmentally conscious alternative for a wide range of industrial applications.
{"title":"Design of antifouling and fire-resistant epoxy composite coatings via rosin–TiO2 hybrid particles and hydrophobic silanes","authors":"Cristian–Dragos Varganici , Immacolata Climaco , Liliana Rosu , Dan Rosu , Amedeo Amoresano , Flavia Zuber , Milijana Jovic , Qun Ren , Sabyasachi Gaan , Antonio Aronne , Claudio Imparato , Aurelio Bifulco","doi":"10.1016/j.polymdegradstab.2025.111845","DOIUrl":"10.1016/j.polymdegradstab.2025.111845","url":null,"abstract":"<div><div>Biofouling poses a critical challenge with significant economic consequences, particularly in the naval industry, where it can increase fuel consumption by up to 40 % due to impaired hydrodynamics. With growing environmental regulations limiting the use of toxic biocides and the increasing demand for high-performing next-generation materials, effective multifunctional protective coatings have never been more desirable. Herein, we present a sustainable solution based on antifouling epoxy-based coatings incorporating rosin-modified hybrid TiO₂ particles, synthesized via the sol-gel method and functionalized in situ with hydrophobic alkylsilanes. Our results demonstrate a robust antibacterial and antifungal effect, driven by the formation of charge transfer complexes between rosin (i.e., a biowaste derived from the secretion of pines) and Ti⁴⁺, which generate reactive oxygen species on the coatings’ surface, effectively inhibiting microbial colonization. The addition of alkylsilanes enhances the antifouling performance by promoting the migration of the hybrid fillers to the surface, conferring superior hydrophobicity and hindering fungal adhesion. Crucially, the synergistic presence of silanes and TiO₂ also delivers a remarkable 38 % reduction in the peak of the heat release rate, boosting fire safety without compromising coating integrity. This work highlights an intriguing waste-to-wealth biocide-free strategy for engineering next-generation flame retardant, antimicrobial, and antifouling coatings, offering a scalable and environmentally conscious alternative for a wide range of industrial applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"244 ","pages":"Article 111845"},"PeriodicalIF":7.4,"publicationDate":"2025-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145746946","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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