Polymer Degradation and Stability最新文献_第4页

Surface modification of carbon dots by boron and phosphorus to construct flame-retardant epoxy resin with high mechanical and low dielectric properties

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-17 DOI: 10.1016/j.polymdegradstab.2025.111275

Lingzhi Wang , Hua Liu , Birong Zeng , Kaibin He , Yiting Xu , Conghui Yuan , Lizong Dai

The effective combination of flame retardant element and carbon dots for the development of epoxy composites with high mechanical property and low dielectric constant in the field of flame retardant material is still a challenge. Herein, the boron and phosphorus dual-element doped carbon dots (BP&NCDs) was synthesized using a simple Kabachnik-Fields reaction, and then incorporated into epoxy resin in different amount to prepare a series of EP/BP&NCDs composites. The optical, thermal stability, mechanical, dielectric and flame-retardant properties were tested by many techniques such as UV–vis spectroscopy, FL, TEM, TG, UL-94 and LOI e.g. It showed that the EP/BP&NCDs composites had favorable transparency, hydrophobicity, mechanical and dielectric properties, while maintaining the photo-luminescent properties. It was worth noting that the EP/3 %-BP&NCDs composite with only 3 % BP&NCDs addition exhibited significant flame-retardant properties with a UL-94 V-0 rating and a limiting oxygen index (LOI) of 31.3 %. Meanwhile, it led to obvious reductions of 34.9 %, 26.6 %, and 15.6 % in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP), respectively. Furthermore, compared with pure EP, the EP/3 %-BP&NCDs composites enhanced the bending strength and impact strength by 32.3 % and 30.3 %, but reduced the dielectric constant and dielectric loss by about 40.0 % and 50.0 %, respectively. When EP/BP&NCDs composites were burned, a continuous and dense carbon layer was formed due to the synergistic action of phosphorus and boron in CDs. Overall the carbon dots (CDs) after surface modification could be applied in epoxy resin system for the achievement of multiple functional EP composites with good flame retardancy, mechanical and dielectric property at low addition, which is helpful to provide a universal strategy in this field.

{"title":"Surface modification of carbon dots by boron and phosphorus to construct flame-retardant epoxy resin with high mechanical and low dielectric properties","authors":"Lingzhi Wang , Hua Liu , Birong Zeng , Kaibin He , Yiting Xu , Conghui Yuan , Lizong Dai","doi":"10.1016/j.polymdegradstab.2025.111275","DOIUrl":"10.1016/j.polymdegradstab.2025.111275","url":null,"abstract":"<div><div>The effective combination of flame retardant element and carbon dots for the development of epoxy composites with high mechanical property and low dielectric constant in the field of flame retardant material is still a challenge. Herein, the boron and phosphorus dual-element doped carbon dots (BP&NCDs) was synthesized using a simple Kabachnik-Fields reaction, and then incorporated into epoxy resin in different amount to prepare a series of EP/BP&NCDs composites. The optical, thermal stability, mechanical, dielectric and flame-retardant properties were tested by many techniques such as UV–vis spectroscopy, FL, TEM, TG, UL-94 and LOI e.g. It showed that the EP/BP&NCDs composites had favorable transparency, hydrophobicity, mechanical and dielectric properties, while maintaining the photo-luminescent properties. It was worth noting that the EP/3 %-BP&NCDs composite with only 3 % BP&NCDs addition exhibited significant flame-retardant properties with a UL-94 V-0 rating and a limiting oxygen index (LOI) of 31.3 %. Meanwhile, it led to obvious reductions of 34.9 %, 26.6 %, and 15.6 % in peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP), respectively. Furthermore, compared with pure EP, the EP/3 %-BP&NCDs composites enhanced the bending strength and impact strength by 32.3 % and 30.3 %, but reduced the dielectric constant and dielectric loss by about 40.0 % and 50.0 %, respectively. When EP/BP&NCDs composites were burned, a continuous and dense carbon layer was formed due to the synergistic action of phosphorus and boron in CDs. Overall the carbon dots (CDs) after surface modification could be applied in epoxy resin system for the achievement of multiple functional EP composites with good flame retardancy, mechanical and dielectric property at low addition, which is helpful to provide a universal strategy in this field.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111275"},"PeriodicalIF":6.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a green polyelectrolyte coating to improve flame retardancy and hygroscopic properties of polyamide 6 fabrics

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-17 DOI: 10.1016/j.polymdegradstab.2025.111274

Pengyu Wang, Jian Liu, Hongfei Li, Xiaoyu Gu, Jun Sun, Sheng Zhang

Polyamide 6 (PA6) fabrics release toxic smoke during combustion, which contributes to environmental pollution and poses a serious threat to human health. In this study, a green polyelectrolyte flame-retardant coating (DT) was built using an ion-exchange reaction method and applied to the surface of PA6 fabric via a simple dipping-padding process. The limiting oxygen index (LOI) of the DT-treated PA6 fabric was increased from 19.1 % for the control PA6 fabric to 23.6 %. The damaged length was reduced from 16.0 cm for the control PA6 fabric to 3.5 cm, and the melt-dripping phenomenon was effectively eliminated. Compared to the control PA6 fabric (559 kW/m²and 22.1 MJ/m²), the heat release rate and total heat release of the DT-treated fabric were significantly reduced to 260.2 kW/m²and 14.7 MJ/m², respectively. Additionally, the DT coating enhanced the hygroscopicity of the PA6 fabric. Char residue analysis showed that the produced phosphoric acid and polyphosphoric acid effectively promoted the formation of a dense, and intumescent char layer, inhibiting the transfer of heat and oxygen. Furthermore, the release of non-flammable gases during combustion diluted the flammable gases, further enhancing the flame-retardant properties of the PA6 fabric. This environmentally friendly flame-retardant polyelectrolyte coating offers a sustainable approach for the development of eco-conscious flame-retardant fabrics.

{"title":"Development of a green polyelectrolyte coating to improve flame retardancy and hygroscopic properties of polyamide 6 fabrics","authors":"Pengyu Wang, Jian Liu, Hongfei Li, Xiaoyu Gu, Jun Sun, Sheng Zhang","doi":"10.1016/j.polymdegradstab.2025.111274","DOIUrl":"10.1016/j.polymdegradstab.2025.111274","url":null,"abstract":"<div><div>Polyamide 6 (PA6) fabrics release toxic smoke during combustion, which contributes to environmental pollution and poses a serious threat to human health. In this study, a green polyelectrolyte flame-retardant coating (DT) was built using an ion-exchange reaction method and applied to the surface of PA6 fabric via a simple dipping-padding process. The limiting oxygen index (LOI) of the DT-treated PA6 fabric was increased from 19.1 % for the control PA6 fabric to 23.6 %. The damaged length was reduced from 16.0 cm for the control PA6 fabric to 3.5 cm, and the melt-dripping phenomenon was effectively eliminated. Compared to the control PA6 fabric (559 kW/m²and 22.1 MJ/m²), the heat release rate and total heat release of the DT-treated fabric were significantly reduced to 260.2 kW/m²and 14.7 MJ/m², respectively. Additionally, the DT coating enhanced the hygroscopicity of the PA6 fabric. Char residue analysis showed that the produced phosphoric acid and polyphosphoric acid effectively promoted the formation of a dense, and intumescent char layer, inhibiting the transfer of heat and oxygen. Furthermore, the release of non-flammable gases during combustion diluted the flammable gases, further enhancing the flame-retardant properties of the PA6 fabric. This environmentally friendly flame-retardant polyelectrolyte coating offers a sustainable approach for the development of eco-conscious flame-retardant fabrics.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111274"},"PeriodicalIF":6.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143464634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Photocatalytic degradation of polystyrene under mild conditions by nanostructured bismuth carbonate

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-16 DOI: 10.1016/j.polymdegradstab.2025.111271

Victor H. Pino-Ramos , E. Bucio , Lucy-Caterine Daza-Gómez , David Díaz

Polystyrene (PS) is a widely used single-use plastic and a major component of global waste. Its overaccumulation poses a critical environmental issue due to its non-biodegradable chemical structure, featuring phenyl moieties and long linear alkanes. Urgent recycling solutions are needed as the problem continues to worsen. In this work, the photodegradation of PS using (BiO)₂CO₃ nanoparticles under UV-light, converting it into useful products like phthalates which have potential applications as plasticizers. The effects of catalyst load and exposure time on the reaction yield are discussed in this research. The (BiO)₂CO₃ nanoparticle powders were obtained by atmospheric CO₂ absorption, and they were characterized using XRD, SEM, HRTEM and SEM-EDS. The oxidized PS was analyzed using FTIR-ATR, TGA, and DSC, confirming successful oxidation at room temperature. The degradation products were identified by FTIR, and their structures verified by NMR ¹H, ¹³C. This approach offers a promising recycling solution for PS waste.

{"title":"Photocatalytic degradation of polystyrene under mild conditions by nanostructured bismuth carbonate","authors":"Victor H. Pino-Ramos , E. Bucio , Lucy-Caterine Daza-Gómez , David Díaz","doi":"10.1016/j.polymdegradstab.2025.111271","DOIUrl":"10.1016/j.polymdegradstab.2025.111271","url":null,"abstract":"<div><div>Polystyrene (PS) is a widely used single-use plastic and a major component of global waste. Its overaccumulation poses a critical environmental issue due to its non-biodegradable chemical structure, featuring phenyl moieties and long linear alkanes. Urgent recycling solutions are needed as the problem continues to worsen. In this work, the photodegradation of PS using (BiO)<sub>2</sub>CO<sub>3</sub> nanoparticles under UV-light, converting it into useful products like phthalates which have potential applications as plasticizers. The effects of catalyst load and exposure time on the reaction yield are discussed in this research. The (BiO)<sub>2</sub>CO<sub>3</sub> nanoparticle powders were obtained by atmospheric CO<sub>2</sub> absorption, and they were characterized using XRD, SEM, HRTEM and SEM-EDS. The oxidized PS was analyzed using FTIR-ATR, TGA, and DSC, confirming successful oxidation at room temperature. The degradation products were identified by FTIR, and their structures verified by NMR <sup>1</sup>H, <sup>13</sup>C. This approach offers a promising recycling solution for PS waste.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111271"},"PeriodicalIF":6.3,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heritage PVC objects: Understanding the diffusion-evaporation of plasticizers

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-15 DOI: 10.1016/j.polymdegradstab.2025.111270

Tjaša Rijavec , Sonia Bujok , Sergii Antropov , G. Asher Newsome , Josep Grau-Bové , Irena Kralj Cigić , Krzysztof Kruczała , Łukasz Bratasz , Matija Strlič

The predominance of diffusion-evaporation of plasticizers in heritage collections is investigated and an analytical method of studying surface exudates based on dry swabbing is introduced for an in-situ museum survey. Most plasticized heritage PVC objects exhibit no visible surface exudates, indicating plasticizer loss is governed by the diffusion-evaporation process and not phase-separation. A new approach to analyzing the diffusion-evaporation process based on experimental data is presented to model plasticizer loss at room conditions. Experiments conducted with historical PVC objects exposed to accelerated degradation for up to 8 weeks at moderate temperatures enable the monitoring of plasticizer loss. Evaluation of the mass loss and the chromatographically determined plasticizer content allows us to determine the temperature dependence of the diffusion coefficient and the surface emission coefficient. Three representative groups of heritage PVC are identified and the activation energies for the coupled diffusion-evaporation processes are used to determine the rate-limiting step and introduce a general model for predicting plasticizer loss from the time of storage, temperature, and thickness of an object. The model can be used as part of risk assessment in heritage PVC collections.

{"title":"Heritage PVC objects: Understanding the diffusion-evaporation of plasticizers","authors":"Tjaša Rijavec , Sonia Bujok , Sergii Antropov , G. Asher Newsome , Josep Grau-Bové , Irena Kralj Cigić , Krzysztof Kruczała , Łukasz Bratasz , Matija Strlič","doi":"10.1016/j.polymdegradstab.2025.111270","DOIUrl":"10.1016/j.polymdegradstab.2025.111270","url":null,"abstract":"<div><div>The predominance of diffusion-evaporation of plasticizers in heritage collections is investigated and an analytical method of studying surface exudates based on dry swabbing is introduced for an <em>in-situ</em> museum survey. Most plasticized heritage PVC objects exhibit no visible surface exudates, indicating plasticizer loss is governed by the diffusion-evaporation process and not phase-separation. A new approach to analyzing the diffusion-evaporation process based on experimental data is presented to model plasticizer loss at room conditions. Experiments conducted with historical PVC objects exposed to accelerated degradation for up to 8 weeks at moderate temperatures enable the monitoring of plasticizer loss. Evaluation of the mass loss and the chromatographically determined plasticizer content allows us to determine the temperature dependence of the diffusion coefficient and the surface emission coefficient. Three representative groups of heritage PVC are identified and the activation energies for the coupled diffusion-evaporation processes are used to determine the rate-limiting step and introduce a general model for predicting plasticizer loss from the time of storage, temperature, and thickness of an object. The model can be used as part of risk assessment in heritage PVC collections.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111270"},"PeriodicalIF":6.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Degradation behavior of polybutylene succinate with fillers

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-15 DOI: 10.1016/j.polymdegradstab.2025.111266

Yosuke Muranaka, Takanari Koike, Tatsuya Osuga, Taisuke Maki

The degradation profiles of poly(butylene succinate) (PBS) with filler were quantitatively evaluated with respect to the degradation rate and the effect of filler content. The types of fillers examined were activated carbon (AC), mesoporous silica, and cellulose nanofiber. Compost degradation and temperature-elevated hydrolysis were performed, and the rate of molecular weight reduction was found to be independent of filler type and content. The ISO 14,855–1 protocol showed no effect of microbial degradation on the molecular weight change profile but did reveal degradation by hydrolysis. The low filler content did not affect the crystallinity or polydispersity index, which suggests that the degradation proceeded uniformly in the crystalline and amorphous phases. However, the crystallinity was lower when the content was high, and the weight decreased at a higher rate. These results suggest that crystallization was inhibited by AC during sample molding, thus promoted the elution of low-molecular-weight components, which were stuck in crystalline regime, from amorphous regime. No AC discharge was observed during temperature-elevated hydrolysis, which was quantitatively confirmed by carbon balance analysis. This finding suggested that the hydrolysis rate of PBS around the AC was very small. The kinetic analysis of the molecular weight change profile of PBS was conducted, and the activation energy of degradation was determined to be 73 kJ/mol. The parameters determined in this study enable the prediction of the time change in the molecular weight of PBS resulting from hydrolysis.

{"title":"Degradation behavior of polybutylene succinate with fillers","authors":"Yosuke Muranaka, Takanari Koike, Tatsuya Osuga, Taisuke Maki","doi":"10.1016/j.polymdegradstab.2025.111266","DOIUrl":"10.1016/j.polymdegradstab.2025.111266","url":null,"abstract":"<div><div>The degradation profiles of poly(butylene succinate) (<strong>PBS</strong>) with filler were quantitatively evaluated with respect to the degradation rate and the effect of filler content. The types of fillers examined were activated carbon (<strong>AC</strong>), mesoporous silica, and cellulose nanofiber. Compost degradation and temperature-elevated hydrolysis were performed, and the rate of molecular weight reduction was found to be independent of filler type and content. The ISO 14,855–1 protocol showed no effect of microbial degradation on the molecular weight change profile but did reveal degradation by hydrolysis. The low filler content did not affect the crystallinity or polydispersity index, which suggests that the degradation proceeded uniformly in the crystalline and amorphous phases. However, the crystallinity was lower when the content was high, and the weight decreased at a higher rate. These results suggest that crystallization was inhibited by AC during sample molding, thus promoted the elution of low-molecular-weight components, which were stuck in crystalline regime, from amorphous regime. No AC discharge was observed during temperature-elevated hydrolysis, which was quantitatively confirmed by carbon balance analysis. This finding suggested that the hydrolysis rate of PBS around the AC was very small. The kinetic analysis of the molecular weight change profile of PBS was conducted, and the activation energy of degradation was determined to be 73 kJ/mol. The parameters determined in this study enable the prediction of the time change in the molecular weight of PBS resulting from hydrolysis.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111266"},"PeriodicalIF":6.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Understanding the degradation and mechanical performance of hyperelastic polylactide copolymers through bulk and ultrathin film analysis correlation

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-15 DOI: 10.1016/j.polymdegradstab.2025.111267

Hanin Alkhamis , Shivam Saretia , Susanne Schwanz , Rainhard Machatschek , Axel T. Neffe , Katarzyna Polak-Kraśna

Appropriate degradation behavior of medical implants is essential, as early degradation of implanted biomaterials can lead to premature loss of mechanical integrity, causing complications such as inflammation and inadequate support during the critical healing period. Therefore, understanding the degradation of newly developed materials for in vivo applications is crucial. Here, we investigated the degradation behavior of blends from Poly[(L-lactide)-co-(ε-caprolactone)] and Poly(D-lactide) (PLLAcoCL/PDLA) in which stereocomplex crystals of the isotactic lactide sequences impart hyperelastic behavior. The PLLAcoCL/PDLA blends were studied through in vitro bulk degradation studies (in printed films and electrospun meshes) and in thin-films using the Langmuir technique. Chemical, thermal, and mechanical properties were assessed at different time-points, highlighting the effects of blends composition and stereocomplexation. The PLLAcoCL/PDLA polymer blend shows promising potential as a covering for expandable cardiovascular implants, offering high ultimate strains (up to >700 %), elasticity, stability, and minimal mass loss during the crucial early healing period (4 weeks). Mechanical data suggest that specific blend ratios, particularly the 95:5 ratio in electrospun meshes, maintained mechanical integrity longer than others (E = 5.7 MPa at week 9), which was reflected in the mass loss of meshes (remaining mass = 67 wt% at week 20). Lower PDLA content accelerated early degradation while enhancing oxidative resistance, whereas higher PDLA content slowed degradation but increased crystallinity. These findings emphasize how blend composition influences degradation rates, mechanical behavior, and stability. Findings highlight the role of composition in tailoring implant degradation and support predictive modeling for cardiovascular applications.

{"title":"Understanding the degradation and mechanical performance of hyperelastic polylactide copolymers through bulk and ultrathin film analysis correlation","authors":"Hanin Alkhamis , Shivam Saretia , Susanne Schwanz , Rainhard Machatschek , Axel T. Neffe , Katarzyna Polak-Kraśna","doi":"10.1016/j.polymdegradstab.2025.111267","DOIUrl":"10.1016/j.polymdegradstab.2025.111267","url":null,"abstract":"<div><div>Appropriate degradation behavior of medical implants is essential, as early degradation of implanted biomaterials can lead to premature loss of mechanical integrity, causing complications such as inflammation and inadequate support during the critical healing period. Therefore, understanding the degradation of newly developed materials for in vivo applications is crucial. Here, we investigated the degradation behavior of blends from Poly[(L-lactide)-co-(ε-caprolactone)] and Poly(D-lactide) (PLLAcoCL/PDLA) in which stereocomplex crystals of the isotactic lactide sequences impart hyperelastic behavior. The PLLAcoCL/PDLA blends were studied through in vitro bulk degradation studies (in printed films and electrospun meshes) and in thin-films using the Langmuir technique. Chemical, thermal, and mechanical properties were assessed at different time-points, highlighting the effects of blends composition and stereocomplexation. The PLLAcoCL/PDLA polymer blend shows promising potential as a covering for expandable cardiovascular implants, offering high ultimate strains (up to >700 %), elasticity, stability, and minimal mass loss during the crucial early healing period (4 weeks). Mechanical data suggest that specific blend ratios, particularly the 95:5 ratio in electrospun meshes, maintained mechanical integrity longer than others (<em>E</em> = 5.7 MPa at week 9), which was reflected in the mass loss of meshes (remaining mass = 67 wt% at week 20). Lower PDLA content accelerated early degradation while enhancing oxidative resistance, whereas higher PDLA content slowed degradation but increased crystallinity. These findings emphasize how blend composition influences degradation rates, mechanical behavior, and stability. Findings highlight the role of composition in tailoring implant degradation and support predictive modeling for cardiovascular applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111267"},"PeriodicalIF":6.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Microwave-Assisted oxidative degradation of poly(vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene): Preparation, characterization, and reaction mechanism

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-15 DOI: 10.1016/j.polymdegradstab.2025.111269

Ranran Qi, Ziwen Gan, Qi Wang, Xiaojie Zhang, Mingyi Liao

In this study, microwave (MW)-assisted oxidative degradation of poly(vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene) (P(VDF-TFE-HFP)) was applied to synthesize carboxy-terminated liquid fluororubber, referred to as LTCFs-246. The resulting product has a carboxyl content of 3.01%, a number-average molecular weight (Mn) of 2100 g/mol, and a polydispersity index (PDI) of 1.61. The product's structure was characterized and analyzed in detail using techniques such as ¹⁹F NMR, UV–Vis, and FTIR spectroscopy. Results indicate that the selective dehydrofluorination reaction (K_HF reaction) primarily occurs on four sequence structures: HFP-VDF-HFP, HFP-VDF-TFE, TFE-VDF-HFP, and TFE-VDF-TFE, with similar degrees of reactivity across these structures. Two types of C=C bonds were formed in the LTCFs-246 backbone, primarily through Hofmann elimination and, to a lesser extent, Zaitsev elimination. The oxidative reaction (K_C-C reaction) was temperature-dependent. At lower temperatures, H₂O₂ decomposed slowly, limiting the K_C-C reaction; as the temperature increased, H₂O₂ rapidly decomposed, actively engaging in the K_C-C reaction and extensively consuming C=C bonds. Once H₂O₂ was fully consumed, the K_C-C reaction ceased, while the K_HF reaction continued uninterrupted. In conclusion, this study provides strong evidence to advance the understanding of the oxidative degradation mechanism of MW-assisted P(VDF-TFE-HFP).

{"title":"Microwave-Assisted oxidative degradation of poly(vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene): Preparation, characterization, and reaction mechanism","authors":"Ranran Qi, Ziwen Gan, Qi Wang, Xiaojie Zhang, Mingyi Liao","doi":"10.1016/j.polymdegradstab.2025.111269","DOIUrl":"10.1016/j.polymdegradstab.2025.111269","url":null,"abstract":"<div><div>In this study, microwave (MW)-assisted oxidative degradation of poly(vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene) (P(VDF-TFE-HFP)) was applied to synthesize carboxy-terminated liquid fluororubber, referred to as LTCFs-246. The resulting product has a carboxyl content of 3.01%, a number-average molecular weight (Mn) of 2100 g/mol, and a polydispersity index (PDI) of 1.61. The product's structure was characterized and analyzed in detail using techniques such as <sup>19</sup>F NMR, UV–Vis, and FTIR spectroscopy. Results indicate that the selective dehydrofluorination reaction (K<sub>HF</sub> reaction) primarily occurs on four sequence structures: HFP-VDF-HFP, HFP-VDF-TFE, TFE-VDF-HFP, and TFE-VDF-TFE, with similar degrees of reactivity across these structures. Two types of C=C bonds were formed in the LTCFs-246 backbone, primarily through Hofmann elimination and, to a lesser extent, Zaitsev elimination. The oxidative reaction (K<sub>C-C</sub> reaction) was temperature-dependent. At lower temperatures, H<sub>2</sub>O<sub>2</sub> decomposed slowly, limiting the K<sub>C-C</sub> reaction; as the temperature increased, H<sub>2</sub>O<sub>2</sub> rapidly decomposed, actively engaging in the K<sub>C-C</sub> reaction and extensively consuming C=C bonds. Once H<sub>2</sub>O<sub>2</sub> was fully consumed, the K<sub>C-C</sub> reaction ceased, while the K<sub>HF</sub> reaction continued uninterrupted. In conclusion, this study provides strong evidence to advance the understanding of the oxidative degradation mechanism of MW-assisted P(VDF-TFE-HFP).</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"235 ","pages":"Article 111269"},"PeriodicalIF":6.3,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synthesis and characterization of block copolymers consisting of poly(ethylene succinate) and poly(amino acid)s

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-13 DOI: 10.1016/j.polymdegradstab.2025.111265

Sumito Kumagai , Motosuke Imada , Senri Hayashi , Atsushi Katsuragi , Kaoko Sato , Hideki Abe , Noriyuki Asakura , Yasumasa Takenaka

In this study, novel block copolymers consisting of poly(ethylene succinate) (PES) and poly(amino acid)s were synthesized, and their thermal and mechanical properties and biodegradability characteristics were investigated. Various types of poly(amino acid) units were successfully introduced using N-phenyloxycarbonyl amino acids (NPCs). The reactions between the terminally aminated PES and the NPCs were conducted by heating in N,N-dimethylacetamide at 65 °C. Structural analyses of the obtained polymers confirmed that the reaction with the NPCs proceeded from both ends of the terminally aminated PES. The results of material property measurements demonstrated that the melting point of the block copolymer containing poly(alanine) units increased beyond 200 °C while that of the original PES was ∼100 °C. Additionally, its strain at break increased ∼80-fold compared to that of PES with a similar molecular weight. The results of biodegradability tests using a soil suspension as an inoculum indicated that some of the block copolymers underwent biodegradation, and a correlation was observed between the biodegradability and the type and feed amount of NPC. Therefore, it was proposed that the degree, rate, and onset time of biodegradation could be controlled by altering the type and amount of incorporated poly(amino acid) units. This research may contribute to the optimal and facile synthesis of polyester-b-poly(amino acid) copolymers and to the expansion of the range of available biodegradable materials.

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引用次数: 0

In situ assembly of polyphosphazene on Fe-MMT nanosheets for high-performance flame-retardant epoxy composites

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-12 DOI: 10.1016/j.polymdegradstab.2025.111264

Keqing Zhou , Yaqin Wu , Lian Yin , Jianjian Luo , Kaihua Lu , Bin Yu , Yongqian Shi , Sheng Zhang , Shizhen Jia

Epoxy resin is a widely utilized thermosetting polymer, however, its flammability and brittleness significantly hinder its broader application and development. This study introduces a novel polyphosphazene modified iron-based montmorillonite (Fe-OMMT@PZS), aimed at enhancing the characteristics of advanced EP composites. These results revealed that Fe-OMMT@PZS was not only evenly dispersed within the EP matrix, but also enhanced the thermal stability and fire resistance of EP composites. In comparison to pure EP, the EP/Fe-OMMT@PZS 10 composites exhibited reductions of 57.1%, 20.5%, 50%, 44.4%, 60%, and 56% in the peak heat release rate (PHRR), total heat release (THR), peak smoke production rate (PSPR), total smoke production (TSP), peak carbon monoxide production rate (PCO), and peak carbon dioxide production rate (PCO₂), respectively. The outstanding fire safety performance was attributed to catalytic carbonization induced by metal compounds and phosphates, the capture of free radicals in gas phase, and dilution effect by non-combustible gases, and the physical barrier created by the Fe-OMMT nanosheets. Furthermore, when the Fe-OMMT@PZS content reached 3 wt%, the composites demonstrated significant improvements in mechanical properties, with increases of 58.8%, 94.6% and 161.9% in elongation at break, tensile strength and tensile modulus, respectively, demonstrating outstanding toughness enhancement. This research provides an effective strategy for tackling the balance between mechanical properties and flame resistance.

环氧树脂是一种应用广泛的热固性聚合物，但其易燃性和脆性极大地阻碍了它的广泛应用和发展。本研究介绍了一种新型聚磷酸盐改性铁基蒙脱石（Fe-OMT@PZS），旨在增强先进 EP 复合材料的特性。研究结果表明，Fe-OMT@PZS 不仅能均匀地分散在 EP 基体中，还能增强 EP 复合材料的热稳定性和耐火性。与纯 EP 相比，EP/Fe-OMMT@PZS 10 复合材料的峰值放热率 (PHRR)、总放热率 (THR)、峰值产烟率 (PSPR)、总产烟率 (TSP)、峰值一氧化碳产率 (PCO) 和峰值二氧化碳产率 (PCO2) 分别降低了 57.1%、20.5%、50%、44.4%、60% 和 56%。出色的消防安全性能归功于金属化合物和磷酸盐的催化碳化、气相中自由基的捕获、不可燃气体的稀释作用以及 Fe-OMMT 纳米片形成的物理屏障。此外，当 Fe-OMMT@PZS 的含量达到 3 wt% 时，复合材料的力学性能得到了显著改善，断裂伸长率、拉伸强度和拉伸模量分别提高了 58.8%、94.6% 和 161.9%，显示出突出的韧性增强效果。这项研究为解决机械性能和阻燃性之间的平衡问题提供了一种有效的策略。

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引用次数: 0

Simultaneously-enhanced flame retardancy, mechanical property and acid/alkali corrosion resistance of ethylene vinyl acetate/aluminum trihydrate composite induced by crosslinking and microencapsulated expandable graphite

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability

Pub Date : 2025-02-11 DOI: 10.1016/j.polymdegradstab.2025.111263

Haoqi Xing , Jiaqi Li , Mengna Liu , Xuefan Yang , Jichun Liu , Bingli Pan , Haibo Chang

The most noticeable problem of aluminum trihydrate (ATH) as a flame retardant for polymers is its low efficiency and poor acid/alkali corrosion resistance. Herein, ethylene vinyl acetate (EVA) was chosen as polymer matrix and a blend of EVA18 (EVA with 18 % vinyl acetate, VA) and EVA40 (EVA with 40 % VA) was crosslinked properly. Microencapsulated expandable graphite (MEG) was introduced into crosslinked EVA (CLEVA) blend/ATH composite. The obtained CLEVA blend/ATH/MEG composite was investigated regarding its various properties. Results evince that ATH's fire-retarding efficiency is very low and up to 65 wt% ATH must be incorporated in order to confer ample flame retardancy on EVA. The CLEVA blend/ATH/MEG composite with 37 wt% ATH and 3 wt% MEG shows highly-enhanced flame retardancy, mechanical property and excellent acid/alkali corrosion resistance simultaneously. Remarkable synergism between ATH and MEG is found in CLEVA, which has elevated flame-retardant efficiency significantly. The increase in mechanical property derives mainly from crosslinking of polymer blend and the intumescent char produced by MEG on composite surface is responsible for the enhanced flame retardancy and corrosion resistance. Partial removal of ATH from the surface of CLEVA/ATH/MEG composite by chemical corrosion has no impact on fire retardancy of this composite. The flame retardation occurs in condensed phase. This work provides an easy and feasible strategy to overcome the drawbacks of ATH in flame-retarded EVA.

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引用次数: 0