Pub Date : 2024-11-13DOI: 10.1016/j.polymdegradstab.2024.111072
Jinghang Zhu , Yiqun Fang , Ruofan Yang , Yiqing Fu , Guoqing Li , Xiaoyan Bai , Weihong Wang , Yongming Song , Qingwen Wang
In this study, a fully bio-based intumescent flame retardant, phytic acid vanillin arginine salt (VR-PA), was designed and synthesized by l-arginine (AR) and vanillin (VA) via a Schiff base reaction, followed by the introduction of phytic acid (PA) using electrostatic ionic interactions. The intumescent flame retardant, VR-PA, was incorporated into wood flour polypropylene composites (WFPP) to enhance their flame retardant and smoke suppression properties. Compared to pure WF, the limiting oxygen index (LOI) of WFPP with 20 wt% VR-PA increased to 28.2 %, while the peak heat release rate and total heat release were reduced by 35.4 % and 20.6 %, respectively. Additionally, the WF with 15 wt% VR-PA exhibited the greatest reduction in total smoke production, with a significant decrease of 42.1 %. The improved flame retardant and smoke suppression performance of the WF is attributed to the free radical trapping effect of VR-PA in the gas phase during the combustion process, as well as the formation of an expanded and continuous carbon layer during in the condensed phase. This study provides a green method to enhance the flame retardancy and smoke suppression of WFPP composites.
{"title":"A fully bio-based intumescent flame retardant for enhancing the flame retardancy and smoke suppression properties of wood flour polypropylene composites","authors":"Jinghang Zhu , Yiqun Fang , Ruofan Yang , Yiqing Fu , Guoqing Li , Xiaoyan Bai , Weihong Wang , Yongming Song , Qingwen Wang","doi":"10.1016/j.polymdegradstab.2024.111072","DOIUrl":"10.1016/j.polymdegradstab.2024.111072","url":null,"abstract":"<div><div>In this study, a fully bio-based intumescent flame retardant, phytic acid vanillin arginine salt (VR-PA), was designed and synthesized by l-arginine (AR) and vanillin (VA) via a Schiff base reaction, followed by the introduction of phytic acid (PA) using electrostatic ionic interactions. The intumescent flame retardant, VR-PA, was incorporated into wood flour polypropylene composites (WFPP) to enhance their flame retardant and smoke suppression properties. Compared to pure WF, the limiting oxygen index (LOI) of WFPP with 20 wt% VR-PA increased to 28.2 %, while the peak heat release rate and total heat release were reduced by 35.4 % and 20.6 %, respectively. Additionally, the WF with 15 wt% VR-PA exhibited the greatest reduction in total smoke production, with a significant decrease of 42.1 %. The improved flame retardant and smoke suppression performance of the WF is attributed to the free radical trapping effect of VR-PA in the gas phase during the combustion process, as well as the formation of an expanded and continuous carbon layer during in the condensed phase. This study provides a green method to enhance the flame retardancy and smoke suppression of WFPP composites.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111072"},"PeriodicalIF":6.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142653356","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 : 2024-11-13DOI: 10.1016/j.polymdegradstab.2024.111086
Tongzhi Zang , Jinzhe Zhang , Yuhan Liu , Siwen Chen , Siyu Han , Jing Guo , Jianshe Hu , Zhipeng Hou , Liqun Yang , Hong Cui
Biodegradable polymeric materials play an important role in the field of clinical science. However, the advancement of non-toxic polymeric materials with excellent performance and controlled degradation properties remains a challenge. Herein, a series of biodegradable and bioresorbable poly (trimethylene carbonate-co-p-dioxanone) [P(TMC-co-PDO), PTD] copolymers were prepared as polymer materials through random copolymerization of trimethylene carbonate (TMC) and p-dioxanone (PDO). In vitro enzymatic degradation mediated by aspergillus oryzae lipase showed that PTD polymer materials exhibit a controllable degradation rate and well form-stability by regulating the PDO content in the composition. The relationship between the chemical structure and the final performance of the PTD copolymers at the molecular level was studied in detail. The results indicate that the introduction of PDO significantly enhances the form-stability of low molecular weight PTMC and significantly accelerates its degradation rate. This initiative provides a feasible strategy for the modification and extensive application of low molecular weight PTMC. It is envisioned that this PTD is a promising candidate for clinical polymer implantable drug delivery systems.
{"title":"Enhancing the degradation properties of poly (trimethylene carbonate) by simple and effective copolymerization of trimethylene carbonate with p-dioxanone","authors":"Tongzhi Zang , Jinzhe Zhang , Yuhan Liu , Siwen Chen , Siyu Han , Jing Guo , Jianshe Hu , Zhipeng Hou , Liqun Yang , Hong Cui","doi":"10.1016/j.polymdegradstab.2024.111086","DOIUrl":"10.1016/j.polymdegradstab.2024.111086","url":null,"abstract":"<div><div>Biodegradable polymeric materials play an important role in the field of clinical science. However, the advancement of non-toxic polymeric materials with excellent performance and controlled degradation properties remains a challenge. Herein, a series of biodegradable and bioresorbable poly (trimethylene carbonate-co-p-dioxanone) [P(TMC-co-PDO), PTD] copolymers were prepared as polymer materials through random copolymerization of trimethylene carbonate (TMC) and <em>p-</em>dioxanone (PDO). In vitro enzymatic degradation mediated by aspergillus oryzae lipase showed that PTD polymer materials exhibit a controllable degradation rate and well form-stability by regulating the PDO content in the composition. The relationship between the chemical structure and the final performance of the PTD copolymers at the molecular level was studied in detail. The results indicate that the introduction of PDO significantly enhances the form-stability of low molecular weight PTMC and significantly accelerates its degradation rate. This initiative provides a feasible strategy for the modification and extensive application of low molecular weight PTMC. It is envisioned that this PTD is a promising candidate for clinical polymer implantable drug delivery systems.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111086"},"PeriodicalIF":6.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699343","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 : 2024-11-12DOI: 10.1016/j.polymdegradstab.2024.111085
Ying Tao, Tianyu Liu, Ming Bao, Xiuyuan Ni
The preparation of high-performance flame retardants specialized for melt-spinning polyamide 66 (PA66) fibers remains a big challenge nowadays. This study has synthesized a highly dispersed, phosphorus-containing titanocene complex, namely Cp2Ti(DBA). The synthesized flame retardant possesses high dispersibility and compatibility in PA66. Flammability tests show that Cp2Ti(DBA) exhibits efficient flame retardancy in PA66. With the addition of 15 wt % of Cp2Ti(DBA) in PA66, a LOI value of 29.9 % is achieved, and the peak heat release rate (PHRR) and total heat release (THR) are reduced by 36 % and 26 %, respectively, as compared to pure PA66. Based on the py-GC MS study and char analysis, Cp2Ti(DBA) shows a dual-phase flame-retardant mechanism. In the gas phase, Cp2Ti(DBA) releases the phosphorus-containing free radicals, which capture the highly reactive free radicals. While in the condensed phase, titanium promotes the phosphaphenanthrene fragments to degrade and retains phosphorus in the form of titanium phosphates, which reinforce the barrier effect and stability of the char layer. This work may provide an efficient flame retardant with promising applications in PA66, especially for the melt-spinning of fibers.
{"title":"The synthesis of an efficient titanium-based flame retardant with high dispersibility in polyamide 66","authors":"Ying Tao, Tianyu Liu, Ming Bao, Xiuyuan Ni","doi":"10.1016/j.polymdegradstab.2024.111085","DOIUrl":"10.1016/j.polymdegradstab.2024.111085","url":null,"abstract":"<div><div>The preparation of high-performance flame retardants specialized for melt-spinning polyamide 66 (PA66) fibers remains a big challenge nowadays. This study has synthesized a highly dispersed, phosphorus-containing titanocene complex, namely Cp<sub>2</sub>Ti(DBA). The synthesized flame retardant possesses high dispersibility and compatibility in PA66. Flammability tests show that Cp<sub>2</sub>Ti(DBA) exhibits efficient flame retardancy in PA66. With the addition of 15 wt % of Cp<sub>2</sub>Ti(DBA) in PA66, a LOI value of 29.9 % is achieved, and the peak heat release rate (PHRR) and total heat release (THR) are reduced by 36 % and 26 %, respectively, as compared to pure PA66. Based on the py-GC MS study and char analysis, Cp<sub>2</sub>Ti(DBA) shows a dual-phase flame-retardant mechanism. In the gas phase, Cp<sub>2</sub>Ti(DBA) releases the phosphorus-containing free radicals, which capture the highly reactive free radicals. While in the condensed phase, titanium promotes the phosphaphenanthrene fragments to degrade and retains phosphorus in the form of titanium phosphates, which reinforce the barrier effect and stability of the char layer. This work may provide an efficient flame retardant with promising applications in PA66, especially for the melt-spinning of fibers.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111085"},"PeriodicalIF":6.3,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699341","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 : 2024-11-12DOI: 10.1016/j.polymdegradstab.2024.111081
Amit K. Jha , Daniella V. Martinez , Jay E. Salinas , Estevan J. Martinez , Ryan D. Davis , Alberto Rodriguez , Hemant Choudhary , Michael S. Kent , Oleg Davydovich
For carbonaceous waste materials that cannot be readily recycled, upcycling through deconstruction and subsequent biological conversion of the breakdown products to fuels, chemicals, or intermediates is a promising strategy. However, deconstructing certain important types of waste plastics such as polyolefins and polystyrene, and also lignin, requires cleaving carbon-carbon bonds. We show that carbon-carbon backbone bonds can be cleaved efficiently by a Fenton reaction in polymers that contain carboxylic acid (COOH) groups. For polyacrylic acid, a model water-soluble polymer, decrease in molecular weight from Mp = 28,000 g/mol to Mp < 700 g/mol occurred with H2O2 loading of only 2 molar equivalents to monomer at pH 4. This method was then applied to partially deconstruct two commercial oxidized polyethylene (oxPE) wax samples with much lower density of COOH groups. A modification of the method, in which dihydroxybenzene was included for a chelator-mediated Fenton (CMF) reaction, greatly increased the deconstruction efficiency. For a sample with acid number of 35 (or ∼ 1 COOH per 114 C atoms), 9.5 % +/- 0.6 % of the carbon was recovered as water-soluble species and an additional 13 % was recovered with subsequent acetone extraction. Mass spectrometry analysis of the water-soluble compounds revealed that most of the low molecular weight fragments form three series, where the members of each series differ by the number of CH2 units. The series contains carboxylic acid and alcohol groups. A panel of microorganisms was tested for growth on this substrate as sole carbon source and several organisms showed promising growth as measured by optical density of cultures at 600 nm. Rhodococcus ruber and Brevundimonas vesicularis grew well on the PE breakdown products with no further carbon or nitrogen sources added whereas Bacillus megaterium, Yarrowia lipolytica MYA 2613, Sphingopyxis witflariensis, and Sphingomonas PWE1 along with Rhodococcus ruber and Brevundimonas vesicularis grew well on the PE breakdown products in the presence of tryptone. Several ideas are discussed to improve the overall conversion with this approach.
{"title":"Deconstruction of carbon-carbon bonded polymers for biological conversion through COOH-functionalization and Fenton chemistry","authors":"Amit K. Jha , Daniella V. Martinez , Jay E. Salinas , Estevan J. Martinez , Ryan D. Davis , Alberto Rodriguez , Hemant Choudhary , Michael S. Kent , Oleg Davydovich","doi":"10.1016/j.polymdegradstab.2024.111081","DOIUrl":"10.1016/j.polymdegradstab.2024.111081","url":null,"abstract":"<div><div>For carbonaceous waste materials that cannot be readily recycled, upcycling through deconstruction and subsequent biological conversion of the breakdown products to fuels, chemicals, or intermediates is a promising strategy. However, deconstructing certain important types of waste plastics such as polyolefins and polystyrene, and also lignin, requires cleaving carbon-carbon bonds. We show that carbon-carbon backbone bonds can be cleaved efficiently by a Fenton reaction in polymers that contain carboxylic acid (COOH) groups. For polyacrylic acid, a model water-soluble polymer, decrease in molecular weight from M<sub>p</sub> = 28,000 g/mol to M<sub>p</sub> < 700 g/mol occurred with H<sub>2</sub>O<sub>2</sub> loading of only 2 molar equivalents to monomer at pH 4. This method was then applied to partially deconstruct two commercial oxidized polyethylene (oxPE) wax samples with much lower density of COOH groups. A modification of the method, in which dihydroxybenzene was included for a chelator-mediated Fenton (CMF) reaction, greatly increased the deconstruction efficiency. For a sample with acid number of 35 (or ∼ 1 COOH per 114 C atoms), 9.5 % +/- 0.6 % of the carbon was recovered as water-soluble species and an additional 13 % was recovered with subsequent acetone extraction. Mass spectrometry analysis of the water-soluble compounds revealed that most of the low molecular weight fragments form three series, where the members of each series differ by the number of CH<sub>2</sub> units. The series contains carboxylic acid and alcohol groups. A panel of microorganisms was tested for growth on this substrate as sole carbon source and several organisms showed promising growth as measured by optical density of cultures at 600 nm. <em>Rhodococcus ruber</em> and <em>Brevundimonas vesicularis</em> grew well on the PE breakdown products with no further carbon or nitrogen sources added whereas <em>Bacillus megaterium, Yarrowia lipolytica</em> MYA 2613<em>, Sphingopyxis witflariensis</em>, and <em>Sphingomonas</em> PWE1 along with <em>Rhodococcus ruber</em> and <em>Brevundimonas vesicularis</em> grew well on the PE breakdown products in the presence of tryptone. Several ideas are discussed to improve the overall conversion with this approach.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111081"},"PeriodicalIF":6.3,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699785","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 : 2024-11-10DOI: 10.1016/j.polymdegradstab.2024.111084
Dali Yang, Alexander S. Edgar, Brennan S. Billow, Jack K. Brett
Many structure/property relationships of hydrolyzed poly(ester urethane) (PEU) – a thermoplastic – have been reported. Examples include changes in molecular weight vs. elongation at break and crosslink density vs. mechanical strength. However, the effect of molecular weight (or molar mass) reduction on some physical, thermal, and chemical properties of hydrolyzed PEU have not been reported. Therefore, a large set of hydrolyzed PEU (Estane®5703) samples were obtained from two aging experiments: 1) accelerated aging conducted under various environments (air, nitrogen, moisture) and at 64 °C and below for almost three years, and 2) natural aging conducted under ambient conditions for more than three decades. The hydrolyzed samples were characterized via multi-detection gel permeation chromatography (GPC), thermogravimetric analysis (TGA), modulated differential scanning calorimetry (mDSC), UV–vis spectroscopy, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy techniques. Hydrolysis of ester linkages in the soft-segments decreases both the molecular weight (Mw) and the melting point (Tm) of Estane (from ∼55 °C to 39 °C). Aging above this Tm, increased mobility of polymer chains and water diffusivity in the PEU matrix alter the PEU degradation pathway from those expected at aging temperatures below this Tm and have significant bearing on the critical molecular weight (MC) at which the physical, chemical, thermal, and mechanical properties of Estane change abruptly. While a MC value of 20 kDa is found for PEU hydrolysis at mild temperatures (e.g., as low as 39 °C), the value of MC increases with increasing aging temperatures. To complement the existing structure/property relationships reported in the literature, more correlations are obtained, which include the effect of Mw on polydispersity, intrinsic viscosity (Mark-Houwink equation), UV extinction coefficient, and dn/dc (GPC analysis) values. Furthermore, we seek to bolster previously reported aging models for PEU by developing a practical model with which the extent of degradation and material performance can be predicted based on aging under different temperature ranges both above and below the melting point of Estane.
{"title":"Hydrolysis of poly(ester urethane): In-depth mechanistic pathway determination through thermal and chemical characterization","authors":"Dali Yang, Alexander S. Edgar, Brennan S. Billow, Jack K. Brett","doi":"10.1016/j.polymdegradstab.2024.111084","DOIUrl":"10.1016/j.polymdegradstab.2024.111084","url":null,"abstract":"<div><div>Many structure/property relationships of hydrolyzed poly(ester urethane) (PEU) – a thermoplastic – have been reported. Examples include changes in molecular weight vs. elongation at break and crosslink density vs. mechanical strength. However, the effect of molecular weight (or molar mass) reduction on some physical, thermal, and chemical properties of hydrolyzed PEU have not been reported. Therefore, a large set of hydrolyzed PEU (Estane®5703) samples were obtained from two aging experiments: 1) accelerated aging conducted under various environments (air, nitrogen, moisture) and at 64 °C and below for almost three years, and 2) natural aging conducted under ambient conditions for more than three decades. The hydrolyzed samples were characterized via multi-detection gel permeation chromatography (GPC), thermogravimetric analysis (TGA), modulated differential scanning calorimetry (mDSC), UV–vis spectroscopy, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy techniques. Hydrolysis of ester linkages in the soft-segments decreases both the molecular weight (M<sub>w</sub>) and the melting point (T<sub>m</sub>) of Estane (from ∼55 °C to 39 °C). Aging above this T<sub>m</sub>, increased mobility of polymer chains and water diffusivity in the PEU matrix alter the PEU degradation pathway from those expected at aging temperatures below this T<sub>m</sub> and have significant bearing on the critical molecular weight (M<sub>C</sub>) at which the physical, chemical, thermal, and mechanical properties of Estane change abruptly. While a M<sub>C</sub> value of 20 kDa is found for PEU hydrolysis at mild temperatures (e.g., as low as 39 °C), the value of M<sub>C</sub> increases with increasing aging temperatures. To complement the existing structure/property relationships reported in the literature, more correlations are obtained, which include the effect of M<sub>w</sub> on polydispersity, intrinsic viscosity (Mark-Houwink equation), UV extinction coefficient, and dn/dc (GPC analysis) values. Furthermore, we seek to bolster previously reported aging models for PEU by developing a practical model with which the extent of degradation and material performance can be predicted based on aging under different temperature ranges both above and below the melting point of Estane.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111084"},"PeriodicalIF":6.3,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743122","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}
Pub Date : 2024-11-10DOI: 10.1016/j.polymdegradstab.2024.111073
Yuhong Zhao , Yu Li , Fei Ma , Xiaolong Xing , Shujuan Wang , Tao Hong , Chengshuang Zhang , Xinli Jing
Phenolic resins (PRs) are one of the most important matrix resins for advanced aerospace thermal protection composites. However, improving the thermal stability and char yield of PRs while maintaining the good processability always remain a challenge. Herein, a resole-type PR (H-BPM), which contained no free phenol and exhibited good processability was synthesized from p, p’-dihydroxy diphenylmethane. The hydroxymethyl content of H-BPM was tuned to obtain resin networks with varied crosslinking density. The total number of crosslinking bridges, methylene bridges and dimethyl ether bridges were proposed to evaluate the different crosslinking bonding content in cured H-BPM, offering a quantitative description of the crosslinked structure. The cured resin with optimized crosslinked structure exhibited excellent thermal stability with a high thermal decomposition temperature of 376°C and a char yield (800°C, nitrogen) of 66%. Additionally, the carbon fabric composites based on optimized resin possesses high interlaminar shear strength of 37 MPa and superior ablative resistance with a linear ablation rate of 0.0195 mm/s and a mass ablation rate of 0.0460 g/s. This study provides new solutions to develop high char yield PRs matrix for ablative resistant composites without introducing any inorganic compounds.
{"title":"Optimization of crosslinked network structure of cured phenolic resin with high char yield","authors":"Yuhong Zhao , Yu Li , Fei Ma , Xiaolong Xing , Shujuan Wang , Tao Hong , Chengshuang Zhang , Xinli Jing","doi":"10.1016/j.polymdegradstab.2024.111073","DOIUrl":"10.1016/j.polymdegradstab.2024.111073","url":null,"abstract":"<div><div>Phenolic resins (PRs) are one of the most important matrix resins for advanced aerospace thermal protection composites. However, improving the thermal stability and char yield of PRs while maintaining the good processability always remain a challenge. Herein, a resole-type PR (H-BPM), which contained no free phenol and exhibited good processability was synthesized from <em>p, p’</em>-dihydroxy diphenylmethane. The hydroxymethyl content of H-BPM was tuned to obtain resin networks with varied crosslinking density. The total number of crosslinking bridges, methylene bridges and dimethyl ether bridges were proposed to evaluate the different crosslinking bonding content in cured H-BPM, offering a quantitative description of the crosslinked structure. The cured resin with optimized crosslinked structure exhibited excellent thermal stability with a high thermal decomposition temperature of 376°C and a char yield (800°C, nitrogen) of 66%. Additionally, the carbon fabric composites based on optimized resin possesses high interlaminar shear strength of 37 MPa and superior ablative resistance with a linear ablation rate of 0.0195 mm/s and a mass ablation rate of 0.0460 g/s. This study provides new solutions to develop high char yield PRs matrix for ablative resistant composites without introducing any inorganic compounds.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111073"},"PeriodicalIF":6.3,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699862","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 : 2024-11-09DOI: 10.1016/j.polymdegradstab.2024.111082
Hongqiang Zhu , Qiufei Chen , Hamza Malik , Yuhang Wang , Jian He , Bomou Ma , Xueli Wang , Hui Zhang , Yong Liu , Jianyong Yu
Understanding and regulating the oxidative stabilization behavior of polyacrylonitrile (PAN) precursor fibers are critical subjects of high-performance carbon fiber production technologies. Here, we performed continuous stabilization and carbonization of PAN fibers at industrial carbon fiber production lines in different locales (different oxygen partial pressure in atmosphere), and investigated the microstructural evolution of the fibers with a systematically analysis at different stages. Influence of oxygen partial pressure in oxidative stabilization atmosphere on tensile modulus of the obtained carbon fibers was obvious. Oxygen diffused into PAN fibers during oxidative stabilization, more homogeneous and crosslinked structures generated under higher oxygen partial pressure atmosphere, and gave the stabilized fibers lower skin-core ratio. The graphite layers gradually generated in the subsequent carbonization stages, and the gathered graphite layers transformed into graphite microcrystalline, the wide-angle x-ray diffraction (WAXD) demonstrated that higher oxygen partial pressure conditions contributed to the generation of higher crystallite preferred orientation and bigger crystallite size, Raman spectroscopy also confirmed the obtained carbon fibers with higher oxygen partial pressure conditions possessed more ordered graphite structures. Thus, relatively higher oxygen partial pressure in air gave the stabilized fibers more crosslinked structures, and contributed to the formation of high-performance carbon fibers.
了解和调节聚丙烯腈（PAN）原纤维的氧化稳定行为是高性能碳纤维生产技术的关键课题。在此，我们在不同地区（不同氧分压环境）的工业碳纤维生产线上对 PAN 纤维进行了连续稳定和碳化，并在不同阶段对纤维的微观结构演变进行了系统分析。氧化稳定气氛中的氧分压对碳纤维拉伸模量的影响非常明显。在氧化稳定过程中，氧气扩散到 PAN 纤维中，在氧分压较高的气氛中产生了更均匀的交联结构，并使稳定后的纤维具有较低的皮芯比。广角 X 射线衍射（WAXD）表明，较高的氧分压条件有助于产生更高的晶粒优选取向和更大的晶粒尺寸，拉曼光谱也证实了在较高氧分压条件下获得的碳纤维具有更有序的石墨结构。因此，空气中相对较高的氧分压使稳定纤维具有更多的交联结构，有助于形成高性能碳纤维。
{"title":"A comparison of the effect of oxygen partial pressure on microstructural evolution of PAN fibers during industrial carbon fiber production line at different altitudes","authors":"Hongqiang Zhu , Qiufei Chen , Hamza Malik , Yuhang Wang , Jian He , Bomou Ma , Xueli Wang , Hui Zhang , Yong Liu , Jianyong Yu","doi":"10.1016/j.polymdegradstab.2024.111082","DOIUrl":"10.1016/j.polymdegradstab.2024.111082","url":null,"abstract":"<div><div>Understanding and regulating the oxidative stabilization behavior of polyacrylonitrile (PAN) precursor fibers are critical subjects of high-performance carbon fiber production technologies. Here, we performed continuous stabilization and carbonization of PAN fibers at industrial carbon fiber production lines in different locales (different oxygen partial pressure in atmosphere), and investigated the microstructural evolution of the fibers with a systematically analysis at different stages. Influence of oxygen partial pressure in oxidative stabilization atmosphere on tensile modulus of the obtained carbon fibers was obvious. Oxygen diffused into PAN fibers during oxidative stabilization, more homogeneous and crosslinked structures generated under higher oxygen partial pressure atmosphere, and gave the stabilized fibers lower skin-core ratio. The graphite layers gradually generated in the subsequent carbonization stages, and the gathered graphite layers transformed into graphite microcrystalline, the wide-angle x-ray diffraction (WAXD) demonstrated that higher oxygen partial pressure conditions contributed to the generation of higher crystallite preferred orientation and bigger crystallite size, Raman spectroscopy also confirmed the obtained carbon fibers with higher oxygen partial pressure conditions possessed more ordered graphite structures. Thus, relatively higher oxygen partial pressure in air gave the stabilized fibers more crosslinked structures, and contributed to the formation of high-performance carbon fibers.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111082"},"PeriodicalIF":6.3,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654172","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}
Cotton is widely used in daily life. However, its flammability limits its application in certain areas. In this study, a novel formaldehyde-free reactive flame retardant, ASBSMP, derived from a bis-triazine ring ammonium phosphonate, was successfully synthesized. The ASBSMP/cotton exhibited excellent flame-retardant properties, with self-extinguishing characteristics and a LIMITING OXYGEN INDEX (LOI) of 41.8 %. Even after 50 washing cycles, the LOI remained at a high level of 30.3 %, indicating outstanding durability. Thermogravimetric analysis (TGA) revealed its superior thermal stability. Cone calorimeter tests further confirmed the superior flame retardancy of the treated cotton, showing a 44.6 % reduction in total heat release (THR) and a 90.1 % reduction in peak heat release rate (PHRR) compared to pure cotton. Results from Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and char residue analyses demonstrated that ASBSMP exhibited flame-retardant activity in both the gas and condensed phases. ASBSMP/cotton exhibited outstanding mechanical integrity for a wide range of applications.
{"title":"A synthetic bis-triazine ring derivative based on ammonium phosphonate towards durable flame-retardant modification of cotton fabrics","authors":"Chenghao Yang, Xin Jin, Xu Li, Xiangji Liu, Zhou Lu, Chaohong Dong","doi":"10.1016/j.polymdegradstab.2024.111083","DOIUrl":"10.1016/j.polymdegradstab.2024.111083","url":null,"abstract":"<div><div>Cotton is widely used in daily life. However, its flammability limits its application in certain areas. In this study, a novel formaldehyde-free reactive flame retardant, ASBSMP, derived from a bis-triazine ring ammonium phosphonate, was successfully synthesized. The ASBSMP/cotton exhibited excellent flame-retardant properties, with self-extinguishing characteristics and a LIMITING OXYGEN INDEX (LOI) of 41.8 %. Even after 50 washing cycles, the LOI remained at a high level of 30.3 %, indicating outstanding durability. Thermogravimetric analysis (TGA) revealed its superior thermal stability. Cone calorimeter tests further confirmed the superior flame retardancy of the treated cotton, showing a 44.6 % reduction in total heat release (THR) and a 90.1 % reduction in peak heat release rate (PHRR) compared to pure cotton. Results from Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), and char residue analyses demonstrated that ASBSMP exhibited flame-retardant activity in both the gas and condensed phases. ASBSMP/cotton exhibited outstanding mechanical integrity for a wide range of applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"231 ","pages":"Article 111083"},"PeriodicalIF":6.3,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699342","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 : 2024-11-07DOI: 10.1016/j.polymdegradstab.2024.111080
Xuchen Wang , Hongqiang Shen , Dahua Shou , Yu Liu , Tianyi Wang , Zhaozhu Zheng , Zeyu Zhao , Xiaoqin Wang , Gang Li
Surgical sutures are essential in wound closure, with different wound sites demanding sutures with specific mechanical properties and biodegradation rates. While silk sutures have a rich history of clinical use, they are typically regarded as nonabsorbable due to their slow degradation in the human body. In this study, we present the development of an absorbable surgical silk suture (ASS) that features controllable biodegradability and mechanical properties, along with excellent biocompatibility and antibacterial attributes. The ASS was created through a straightforward enzymatic hydrolysis process using proteinase K on degummed braided silk sutures. Additionally, we enhance the mechanical properties of the ASS by applying a regenerated silk fibroin (RSF) coating technology, which uses vapor treatment under water and methanol atmospheres. This combination of enzymatic hydrolysis and RSF coating technology allows for the customization of ASS's biodegradation rates while ensuring that the suture diameter and tensile strength comply with the United States Pharmacopeia (USP) standards for absorbable sutures. This innovative approach addresses the dynamic needs of medical professionals and patients alike, providing a novel solution for wound closure.
手术缝合线对伤口闭合至关重要，不同的伤口部位需要具有特定机械性能和生物降解率的缝合线。虽然蚕丝缝合线的临床应用历史悠久，但由于其在人体内降解缓慢，通常被认为是不可吸收的。在本研究中，我们介绍了一种可吸收手术丝缝线（ASS）的开发情况，这种缝线具有可控的生物降解性和机械性能，以及出色的生物相容性和抗菌特性。这种可吸收手术蚕丝缝合线是利用蛋白酶 K 对脱胶编织蚕丝缝合线进行直接酶水解而制成的。此外，我们还采用了再生蚕丝纤维素（RSF）涂层技术，在水和甲醇气氛下进行蒸气处理，从而增强了 ASS 的机械性能。酶水解和 RSF 涂层技术的结合可以定制 ASS 的生物降解率，同时确保缝合线的直径和拉伸强度符合美国药典 (USP) 的可吸收缝合线标准。这种创新方法满足了医疗专业人员和患者的动态需求，为伤口闭合提供了一种新颖的解决方案。
{"title":"A braided surgical silk suture with controllable biodegradability via enzymatic hydrolysis","authors":"Xuchen Wang , Hongqiang Shen , Dahua Shou , Yu Liu , Tianyi Wang , Zhaozhu Zheng , Zeyu Zhao , Xiaoqin Wang , Gang Li","doi":"10.1016/j.polymdegradstab.2024.111080","DOIUrl":"10.1016/j.polymdegradstab.2024.111080","url":null,"abstract":"<div><div>Surgical sutures are essential in wound closure, with different wound sites demanding sutures with specific mechanical properties and biodegradation rates. While silk sutures have a rich history of clinical use, they are typically regarded as nonabsorbable due to their slow degradation in the human body. In this study, we present the development of an absorbable surgical silk suture (ASS) that features controllable biodegradability and mechanical properties, along with excellent biocompatibility and antibacterial attributes. The ASS was created through a straightforward enzymatic hydrolysis process using proteinase K on degummed braided silk sutures. Additionally, we enhance the mechanical properties of the ASS by applying a regenerated silk fibroin (RSF) coating technology, which uses vapor treatment under water and methanol atmospheres. This combination of enzymatic hydrolysis and RSF coating technology allows for the customization of ASS's biodegradation rates while ensuring that the suture diameter and tensile strength comply with the United States Pharmacopeia (USP) standards for absorbable sutures. This innovative approach addresses the dynamic needs of medical professionals and patients alike, providing a novel solution for wound closure.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111080"},"PeriodicalIF":6.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700564","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 : 2024-11-07DOI: 10.1016/j.polymdegradstab.2024.111056
Tong-Yu Bai, Xiang-Xin Xiao, Guan-Qi Zheng, Qin Zhang, Zi-Ni Wang, Li Chen, Bo-Wen Liu, Yu-Zhong Wang
Polycarbonate is a widely used engineering plastic material, but its limited flame retardancy has restricted its application in high-end fields such as aviation and railways. In this study, we propose a novel copolymerization/macromolecular blending strategy to produce a high-performance, fire-safe polycarbonate composite. By copolymerizing with polydimethylsiloxane oligomer and blending with macromolecular polyarylate, the resulting PC-BPDMS5/PITR successfully achieved a UL-94 V-0 rating and a high limiting oxygen index value of 34.2 %. The peak heat release and total smoke release were significantly reduced by 45.2 % and 27.4 %, respectively, compared to pure PC. SEM, Raman, and XPS analyses confirmed the condensed-phase dominated flame-retardant mechanism, attributed to the char-forming ability of the polyarylate and polydimethylsiloxane segments. Polydimethylsiloxane segments can decompose to produce small molecules such as methane, and the left structure with silicon, which undergo cross-linking reactions with the substrate during combustion to promote char formation. The polyaromatic ring structure of PITR can also participate in the formation of a dense and stable char layer. The excellent compatibility between the polyarylate and the PC matrix, combined with the superior flexibility of polydimethylsiloxane, allowed the composite to maintain mechanical properties comparable to pure PC. Additionally, the increased molar volume resulted in a low dielectric constant for PC-BPDMS5/PITR. This work presents a promising approach for the development of high-performance polycarbonate composites.
聚碳酸酯是一种广泛使用的工程塑料材料，但其有限的阻燃性限制了它在航空和铁路等高端领域的应用。在本研究中，我们提出了一种新型共聚/大分子共混策略，以生产高性能、防火安全的聚碳酸酯复合材料。通过与聚二甲基硅氧烷低聚物共聚并与高分子聚芳酸酯共混，制得的 PC-BPDMS5/PITR 成功达到了 UL-94 V-0 等级，极限氧指数值高达 34.2%。与纯 PC 相比，峰值热释放量和总烟雾释放量分别显著降低了 45.2% 和 27.4%。扫描电子显微镜、拉曼和 XPS 分析证实了聚芳酸酯和聚二甲基硅氧烷片段的成炭能力主导了凝聚相阻燃机制。聚二甲基硅氧烷段可分解产生甲烷等小分子，左侧结构中含有硅，在燃烧过程中会与基质发生交联反应，促进炭的形成。PITR 的多芳香族环结构还能参与形成致密稳定的炭层。聚芳酸酯与 PC 基体之间出色的兼容性，再加上聚二甲基硅氧烷优越的柔韧性，使复合材料能够保持与纯 PC 相当的机械性能。此外，摩尔体积的增加使 PC-BPDMS5/PITR 的介电常数降低。这项研究为开发高性能聚碳酸酯复合材料提供了一种前景广阔的方法。
{"title":"Fire-safe and mechanically robust polycarbonate composite enabled by novel copolymerization/macromolecular blending strategy","authors":"Tong-Yu Bai, Xiang-Xin Xiao, Guan-Qi Zheng, Qin Zhang, Zi-Ni Wang, Li Chen, Bo-Wen Liu, Yu-Zhong Wang","doi":"10.1016/j.polymdegradstab.2024.111056","DOIUrl":"10.1016/j.polymdegradstab.2024.111056","url":null,"abstract":"<div><div>Polycarbonate is a widely used engineering plastic material, but its limited flame retardancy has restricted its application in high-end fields such as aviation and railways. In this study, we propose a novel copolymerization/macromolecular blending strategy to produce a high-performance, fire-safe polycarbonate composite. By copolymerizing with polydimethylsiloxane oligomer and blending with macromolecular polyarylate, the resulting PC-BPDMS<sub>5</sub>/PITR successfully achieved a UL-94 V-0 rating and a high limiting oxygen index value of 34.2 %. The peak heat release and total smoke release were significantly reduced by 45.2 % and 27.4 %, respectively, compared to pure PC. SEM, Raman, and XPS analyses confirmed the condensed-phase dominated flame-retardant mechanism, attributed to the char-forming ability of the polyarylate and polydimethylsiloxane segments. Polydimethylsiloxane segments can decompose to produce small molecules such as methane, and the left structure with silicon, which undergo cross-linking reactions with the substrate during combustion to promote char formation. The polyaromatic ring structure of PITR can also participate in the formation of a dense and stable char layer. The excellent compatibility between the polyarylate and the PC matrix, combined with the superior flexibility of polydimethylsiloxane, allowed the composite to maintain mechanical properties comparable to pure PC. Additionally, the increased molar volume resulted in a low dielectric constant for PC-BPDMS<sub>5</sub>/PITR. This work presents a promising approach for the development of high-performance polycarbonate composites.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111056"},"PeriodicalIF":6.3,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654171","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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