This work explores one of the numerous playgrounds offered by polyesters. A series of poly (alkylene trans-1,4-cyclohexanedicarboxylate)s were synthesized combining trans-1,4-cyclohexane dicarboxylic acid with four diols containing an increasing number of methylene groups ( = 3, 4, 5 and 6). The resulting polyesters are fully aliphatic. Their backbones contain cyclic aliphatic moieties and linear aliphatic segments in different relative contents depending on . The flexibility of these polyesters can be finely tuned ( decreases proportionally to the increase in ), however the microstructure dramatically changes depending on whether is an odd or an even number (odd-even effect). On one hand, the odd-numbered samples are easier to melt-quench to a fully amorphous glassy state; on the other hand, the even-numbered samples are prone to crystallization and crystallize very fast. The developed microstructure is complex because of the probable coexistence of different crystalline structures, mesophases, and molecular arrangements depending on the cis/trans isomerism of the cyclohexane moiety. Preliminary tests provided mechanical and barrier properties that could make these polyesters suitable for packaging applications. Composting tests showed that increasing could eventually improve the biodegradation rate of these polyesters, although crystallinity remains the most influencing parameter.
{"title":"Synthesis and properties of poly (alkylene trans-1,4-cyclohexanedicarboxylate)s with different glycolic subunits","authors":"Giulia Guidotti , Clément Fosse , Michelina Soccio , Massimo Gazzano , Valentina Siracusa , Laurent Delbreilh , Antonella Esposito , Nadia Lotti","doi":"10.1016/j.polymdegradstab.2024.111050","DOIUrl":"10.1016/j.polymdegradstab.2024.111050","url":null,"abstract":"<div><div>This work explores one of the numerous playgrounds offered by polyesters. A series of poly (alkylene <em>trans</em>-1,4-cyclohexanedicarboxylate)s were synthesized combining <em>trans</em>-1,4-cyclohexane dicarboxylic acid with four diols containing an increasing number of methylene groups (<span><math><msub><mrow><mi>n</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> = 3, 4, 5 and 6). The resulting polyesters are fully aliphatic. Their backbones contain cyclic aliphatic moieties and linear aliphatic segments in different relative contents depending on <span><math><msub><mrow><mi>n</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>. The flexibility of these polyesters can be finely tuned (<span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>g</mi></mrow></msub></math></span> decreases proportionally to the increase in <span><math><msub><mrow><mi>n</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>), however the microstructure dramatically changes depending on whether <span><math><msub><mrow><mi>n</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> is an odd or an even number (odd-even effect). On one hand, the odd-numbered samples are easier to melt-quench to a fully amorphous glassy state; on the other hand, the even-numbered samples are prone to crystallization and crystallize very fast. The developed microstructure is complex because of the probable coexistence of different crystalline structures, mesophases, and molecular arrangements depending on the <em>cis</em>/<em>trans</em> isomerism of the cyclohexane moiety. Preliminary tests provided mechanical and barrier properties that could make these polyesters suitable for packaging applications. Composting tests showed that increasing <span><math><msub><mrow><mi>n</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> could eventually improve the biodegradation rate of these polyesters, although crystallinity remains the most influencing parameter.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111050"},"PeriodicalIF":6.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579060","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 : 2024-10-30DOI: 10.1016/j.polymdegradstab.2024.111066
Jingsheng Wang , Jun Wang , Fengyi Wang , Shuang Yang , Chaoqun Wu , Xi Chen , Kaiwen Chen , Pingan Song , Hao Wang , Siqi Huo
The escalating need for advanced, fire-resistant, single-component epoxy resin (EP) is fueled by its practicality and economic benefits, highlighting the necessity for the development of multifunctional flame-retardant latent curing agents. Herein, two liquid phosphorus-containing bis-imidazole compounds, PPDM and DPCMI, were synthesized as latent curing agents for EP, demonstrating multiple effects in improving latency, thermal stability, mechanical properties, and fire safety. EP/PPDM and EP/DPCMI showcased superior storage stability and rapid curing at moderate temperatures, with EP/PPDM standing out for its long shelf life of 7 d and being gelled within 18 min at 100 °C. The resulting thermosets presented increased glass transition temperatures (189.5 and 178.9 °C), due to the enhanced crosslinking densities. The presence of bis-imidazole groups in PPDM and DPCMI enabled EPs to form denser crosslinked networks, leading to improved mechanical strength and toughness. The limiting oxygen index (LOI) values of EP/PPDM and EP/DPCMI reached 29.5% and 29.0%, respectively. Compared to the control EP, EP/PPDM and EP/DPCMI showed 23.1% and 18.8% reductions in total heat release and 22.0% and 23.11% decreases in total smoke production. These results confirm the enhanced flame retardancy and smoke suppression of EP/PPDM and EP/DPCMI because of introducing phosphorus-containing groups. Even though the curing time was halved to 2.5 hours, EP/PPDM systems maintained satisfactory overall performances. Therefore, this work offers a scalable strategy for the fabrication of single-component EP systems combining rapid curing, satisfactory flame retardancy, and enhanced thermal stability and mechanical properties, aligning with the needs of industrial applications.
{"title":"Liquid phosphorus-based bis-imidazole compounds as latent curing agents for enhancing thermal, mechanical, and flame-retardant performances of single-component epoxy resins","authors":"Jingsheng Wang , Jun Wang , Fengyi Wang , Shuang Yang , Chaoqun Wu , Xi Chen , Kaiwen Chen , Pingan Song , Hao Wang , Siqi Huo","doi":"10.1016/j.polymdegradstab.2024.111066","DOIUrl":"10.1016/j.polymdegradstab.2024.111066","url":null,"abstract":"<div><div>The escalating need for advanced, fire-resistant, single-component epoxy resin (EP) is fueled by its practicality and economic benefits, highlighting the necessity for the development of multifunctional flame-retardant latent curing agents. Herein, two liquid phosphorus-containing bis-imidazole compounds, PPDM and DPCMI, were synthesized as latent curing agents for EP, demonstrating multiple effects in improving latency, thermal stability, mechanical properties, and fire safety. EP/PPDM and EP/DPCMI showcased superior storage stability and rapid curing at moderate temperatures, with EP/PPDM standing out for its long shelf life of 7 d and being gelled within 18 min at 100 °C. The resulting thermosets presented increased glass transition temperatures (189.5 and 178.9 °C), due to the enhanced crosslinking densities. The presence of bis-imidazole groups in PPDM and DPCMI enabled EPs to form denser crosslinked networks, leading to improved mechanical strength and toughness. The limiting oxygen index (LOI) values of EP/PPDM and EP/DPCMI reached 29.5% and 29.0%, respectively. Compared to the control EP, EP/PPDM and EP/DPCMI showed 23.1% and 18.8% reductions in total heat release and 22.0% and 23.11% decreases in total smoke production. These results confirm the enhanced flame retardancy and smoke suppression of EP/PPDM and EP/DPCMI because of introducing phosphorus-containing groups. Even though the curing time was halved to 2.5 hours, EP/PPDM systems maintained satisfactory overall performances. Therefore, this work offers a scalable strategy for the fabrication of single-component EP systems combining rapid curing, satisfactory flame retardancy, and enhanced thermal stability and mechanical properties, aligning with the needs of industrial applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111066"},"PeriodicalIF":6.3,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593278","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 : 2024-10-28DOI: 10.1016/j.polymdegradstab.2024.111055
Suha Lee , Jung-Wook Wee
Understanding the long-term durability of 3D-printed polymeric materials under varying temperature and humidity conditions is essential for expanding their industrial applications. Therefore, it is critical to assess the impact of degradation on mechanical properties such as tensile strength. In this study, we manufactured specimens with dual orientations by additive manufacturing-based 3D printing and subjected them to accelerated degradation under various temperature and humidity conditions to evaluate their durability in degradation environments. Mechanical properties significantly decreased under the most severe conditions, with a maximum reduction of 76.7 % observed in molecular weight. The deconvolution of the molecular weight distribution and its correlation with mechanical properties were thoroughly investigated. We derived an equation representing the relationship between the peaks obtained from deconvoluting the molecular weight distribution and the tensile strength. Furthermore, to expedite and simplify tensile strength assessment, we trained an artificial neural network (ANN) model using tensile test results to construct a predictive model. The ANN utilized temperature, humidity, printing angle, and time as input data, with tensile strength as the output. Validation of this model demonstrated the capability to predict tensile strength accurately under different temperature and humidity conditions.
{"title":"Effect of temperature and relative humidity on hydrolytic degradation of additively manufactured PLA: Characterization and artificial neural network modeling","authors":"Suha Lee , Jung-Wook Wee","doi":"10.1016/j.polymdegradstab.2024.111055","DOIUrl":"10.1016/j.polymdegradstab.2024.111055","url":null,"abstract":"<div><div>Understanding the long-term durability of 3D-printed polymeric materials under varying temperature and humidity conditions is essential for expanding their industrial applications. Therefore, it is critical to assess the impact of degradation on mechanical properties such as tensile strength. In this study, we manufactured specimens with dual orientations by additive manufacturing-based 3D printing and subjected them to accelerated degradation under various temperature and humidity conditions to evaluate their durability in degradation environments. Mechanical properties significantly decreased under the most severe conditions, with a maximum reduction of 76.7 % observed in molecular weight. The deconvolution of the molecular weight distribution and its correlation with mechanical properties were thoroughly investigated. We derived an equation representing the relationship between the peaks obtained from deconvoluting the molecular weight distribution and the tensile strength. Furthermore, to expedite and simplify tensile strength assessment, we trained an artificial neural network (ANN) model using tensile test results to construct a predictive model. The ANN utilized temperature, humidity, printing angle, and time as input data, with tensile strength as the output. Validation of this model demonstrated the capability to predict tensile strength accurately under different temperature and humidity conditions.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111055"},"PeriodicalIF":6.3,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572273","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 : 2024-10-26DOI: 10.1016/j.polymdegradstab.2024.111052
Yichen Chen , Xiaodong Jin , Wanfu Wang , Wufei Tang , Chenhao Liu , Shibing Sun
In this work, a novel single molecule flame retardant (DT-S) was synthesized through the self-assembly of diethyltriamine penta-(methylphosphonic) acid and sulfanilamide. Additionally, the three-dimensional sea urchin-like layered double hydroxide hollow dodecahedral structure (MOFs-LDH) was etched from a MOF to increase specific surface area and reaction sites. The chemical structures of DT-S and MOFs-LDH were comprehensively characterized. Subsequently, the obtained flame retardants were molten-compounding into PLA matrix. The fire performance of PLA composites was evaluated by limiting oxygen index (LOI), vertical combustion (UL-94), and cone calorimeter tests. Compared with neat PLA sample, the inclusion of 3 % DT-S and 2 % MOFs-LDH led to an increase in the LOI value from 19.9 to 35.0 %, an upgrade in the UL-94 rating from none to V-0, and a reduction in the peak heat release rate from 524.4 to 401.2 kW m−2. Analysis of the decomposition products of the PLA composites and the observation of char morphology suggested that DT-S and MOFs-LDH took effects in both condensed phase and gas phase. Furthermore, the evaluation of the UV protection performance using a UV–visible near-infrared spectrophotometer indicated an enhancement in the UV protection performance of PLA, achieving an "excellent" level in evaluating UV protection performance (UPF 50+).
{"title":"Biomimetic synthesis of sea urchin-Like MOFs-LDH and ternary synergistic flame retardants to improve the flame retardancy and UV resistance of Polylactic acid","authors":"Yichen Chen , Xiaodong Jin , Wanfu Wang , Wufei Tang , Chenhao Liu , Shibing Sun","doi":"10.1016/j.polymdegradstab.2024.111052","DOIUrl":"10.1016/j.polymdegradstab.2024.111052","url":null,"abstract":"<div><div>In this work, a novel single molecule flame retardant (DT-S) was synthesized through the self-assembly of diethyltriamine penta-(methylphosphonic) acid and sulfanilamide. Additionally, the three-dimensional sea urchin-like layered double hydroxide hollow dodecahedral structure (MOFs-LDH) was etched from a MOF to increase specific surface area and reaction sites. The chemical structures of DT-S and MOFs-LDH were comprehensively characterized. Subsequently, the obtained flame retardants were molten-compounding into PLA matrix. The fire performance of PLA composites was evaluated by limiting oxygen index (LOI), vertical combustion (UL-94), and cone calorimeter tests. Compared with neat PLA sample, the inclusion of 3 % DT-S and 2 % MOFs-LDH led to an increase in the LOI value from 19.9 to 35.0 %, an upgrade in the UL-94 rating from none to V-0, and a reduction in the peak heat release rate from 524.4 to 401.2 kW <em>m</em><sup>−2</sup>. Analysis of the decomposition products of the PLA composites and the observation of char morphology suggested that DT-S and MOFs-LDH took effects in both condensed phase and gas phase. Furthermore, the evaluation of the UV protection performance using a UV–visible near-infrared spectrophotometer indicated an enhancement in the UV protection performance of PLA, achieving an \"excellent\" level in evaluating UV protection performance (UPF 50+).</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111052"},"PeriodicalIF":6.3,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572274","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 : 2024-10-26DOI: 10.1016/j.polymdegradstab.2024.111054
Ruilong Li , Yao chen , Honglin Lian , Jianbing Guo , Xiaolang Chen , Junliang Li , Yongzhi Meng , Hong Wu
Maintaining a delicate balance between flame retardancy and amount of expandable graphite (EG) in flame retardant polypropylene (PP) is still a formidable challenge, primarily due to the lower flame-retardant efficiency of EG. In order to address this concern, a novel cobalt-doped nanosheet flame retardant (PAMA-Co) was fabricated by a hydrothermal method utilizing phytic acid (PA) and melamine (MA), exhibiting a promising potential in constructing synergistic EG flame retardant PP. Significantly, the incorporation of only 7 wt% PAMA-Co/23 wt% EG system raises the limiting oxygen index (LOI) of PP to 27.3% and UL-94 V0 level, which indicates the excellent synergistic flame-retardant efficiency of PAMA-Co. Furthermore, both the peak heat release rate (PHRR) and the peak smoke production rate (PSPR) of PP composites with 7 wt% PAMA-Co/23 wt% EG are substantially reduced, exhibiting an 81.6% lower PHRR and 87.8% PSPR compared to pure PP. The excellent flame-retardant efficiency is attributed to the following mechanisms: Gas-phase dilution, catalytic cross-linking charring effect, and the suppression of the EG “popcorn effect” of PAMA-Co. In summary, this work not only advances an understanding of flame-retardant mechanisms but also offers a practical, green strategy for enhancing the safety and utility of PP in various applications.
{"title":"Efficient flame retardancy of polypropylene by cobalt ions doped phytate melamine synergized with expandable graphite","authors":"Ruilong Li , Yao chen , Honglin Lian , Jianbing Guo , Xiaolang Chen , Junliang Li , Yongzhi Meng , Hong Wu","doi":"10.1016/j.polymdegradstab.2024.111054","DOIUrl":"10.1016/j.polymdegradstab.2024.111054","url":null,"abstract":"<div><div>Maintaining a delicate balance between flame retardancy and amount of expandable graphite (EG) in flame retardant polypropylene (PP) is still a formidable challenge, primarily due to the lower flame-retardant efficiency of EG. In order to address this concern, a novel cobalt-doped nanosheet flame retardant (PAMA-Co) was fabricated by a hydrothermal method utilizing phytic acid (PA) and melamine (MA), exhibiting a promising potential in constructing synergistic EG flame retardant PP. Significantly, the incorporation of only 7 wt% PAMA-Co/23 wt% EG system raises the limiting oxygen index (LOI) of PP to 27.3% and UL-94 V0 level, which indicates the excellent synergistic flame-retardant efficiency of PAMA-Co. Furthermore, both the peak heat release rate (PHRR) and the peak smoke production rate (PSPR) of PP composites with 7 wt% PAMA-Co/23 wt% EG are substantially reduced, exhibiting an 81.6% lower PHRR and 87.8% PSPR compared to pure PP. The excellent flame-retardant efficiency is attributed to the following mechanisms: Gas-phase dilution, catalytic cross-linking charring effect, and the suppression of the EG “popcorn effect” of PAMA-Co. In summary, this work not only advances an understanding of flame-retardant mechanisms but also offers a practical, green strategy for enhancing the safety and utility of PP in various applications.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111054"},"PeriodicalIF":6.3,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554154","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 : 2024-10-26DOI: 10.1016/j.polymdegradstab.2024.111053
Sara Adeleh , Roland Bol , Tabea Becker , Sonja Herres-Pawlis , Harry Vereecken , Thomas Pütz
The production of bio-based polymers as replacements for fossil-based ones is becoming increasingly important to the human society due to the decreasing availability of fossil resources combined with rising fuel prices, and their potential to reduce greenhouse gas emissions that are the main cause of climate change. There is strong societal and regulatory pressure for the development of more sustainable biodegradable bioplastics. Viable recycling options are still lacking for many of these plastics. Due to the novelty of biodegradable bioplastics valuable chains, more research is required to reduce technical and economic uncertainties and demonstrate the feasibility and economic competitiveness of them. Therefore, there is an urgent need for technology development and the design of transition paths towards structural changes in polymers establishing local and regional circular production of bioplastics with potential impact on global economies.
It is essential to understand the factors that control the environmental behavior and fate of such bioplastics as well as their impact on ecosystem functioning. Extensive studies with accurate measurement tools and specialized analytical techniques are needed for this purpose. The radiolabeling technique (14C) allows the quantification of the degradation process of biopolymers by easily being able to distinguish between CO2 which is produced during degradation polymers and other carbon sources in natural environment.
This review provides an overview of the application of the 14C-labeling technique in polymer degradation studies that is compared under various conditions. In following, standard methods for 14C-labeling, as well as its potentials, obstacles, and deficiencies in usage, are also discussed.
{"title":"Radiolabeling for polymers degradation studies: Opportunities and challenges ahead","authors":"Sara Adeleh , Roland Bol , Tabea Becker , Sonja Herres-Pawlis , Harry Vereecken , Thomas Pütz","doi":"10.1016/j.polymdegradstab.2024.111053","DOIUrl":"10.1016/j.polymdegradstab.2024.111053","url":null,"abstract":"<div><div>The production of bio-based polymers as replacements for fossil-based ones is becoming increasingly important to the human society due to the decreasing availability of fossil resources combined with rising fuel prices, and their potential to reduce greenhouse gas emissions that are the main cause of climate change. There is strong societal and regulatory pressure for the development of more sustainable biodegradable bioplastics. Viable recycling options are still lacking for many of these plastics. Due to the novelty of biodegradable bioplastics valuable chains, more research is required to reduce technical and economic uncertainties and demonstrate the feasibility and economic competitiveness of them. Therefore, there is an urgent need for technology development and the design of transition paths towards structural changes in polymers establishing local and regional circular production of bioplastics with potential impact on global economies.</div><div>It is essential to understand the factors that control the environmental behavior and fate of such bioplastics as well as their impact on ecosystem functioning. Extensive studies with accurate measurement tools and specialized analytical techniques are needed for this purpose. The radiolabeling technique (<sup>14</sup>C) allows the quantification of the degradation process of biopolymers by easily being able to distinguish between CO<sub>2</sub> which is produced during degradation polymers and other carbon sources in natural environment.</div><div>This review provides an overview of the application of the <sup>14</sup>C-labeling technique in polymer degradation studies that is compared under various conditions. In following, standard methods for <sup>14</sup>C-labeling, as well as its potentials, obstacles, and deficiencies in usage, are also discussed.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111053"},"PeriodicalIF":6.3,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572275","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}
The premature failure of bioresorbable self-expanding stents for peripheral arterial disease could lead to form thrombosis and threaten patients′ lives. Predicting the time and cause of mechanical and structural failure is crucial to prevent premature failure of implanted stents. Herein, we report a situ accelerated hydrolysis to investigate the degradation properties of self-expanding stents braided by high-performance Poly(L-lactic acid) (PLLA) monofilaments in an accelerated term over a formal long one. Degradation, microstructure, and mechanical properties were comprehensively evaluated to identify key factors of the failure during lifetime. The results show that the upper temperature limit for accelerated hydrolysis is 50 °C. The mechanical properties undergo multiple stages of functional holding, decreasing, and eventual failure. It is attributed to uneven degradation and distribution of crystalline and amorphous regions. Specifically, the disappearance of amorphous chains between fibrils at 6 months leads to mechanical failure. Further disappearance of amorphous chains within fibrils at 18 months results in structural disintegration. Additionally, the degradation behavior of the stents and potential effects of degradation products on vascular tissues are validated for predictive accuracy. These insights provide valuable experimental references for optimizing design and clinical application of PLLA-based self-expanding stents.
{"title":"Failure signal of high orientation Poly(L-lactic acid) monofilament for self-expanding stent during lifetime: Disappeared amorphous connections","authors":"Bin Wang, Jinbo Liu, Xue Hu, Chen Zhang, Qingwei Liu, Zhonghua Ni, Gutian Zhao","doi":"10.1016/j.polymdegradstab.2024.111044","DOIUrl":"10.1016/j.polymdegradstab.2024.111044","url":null,"abstract":"<div><div>The premature failure of bioresorbable self-expanding stents for peripheral arterial disease could lead to form thrombosis and threaten patients′ lives. Predicting the time and cause of mechanical and structural failure is crucial to prevent premature failure of implanted stents. Herein, we report a situ accelerated hydrolysis to investigate the degradation properties of self-expanding stents braided by high-performance Poly(L-lactic acid) (PLLA) monofilaments in an accelerated term over a formal long one. Degradation, microstructure, and mechanical properties were comprehensively evaluated to identify key factors of the failure during lifetime. The results show that the upper temperature limit for accelerated hydrolysis is 50 °C. The mechanical properties undergo multiple stages of functional holding, decreasing, and eventual failure. It is attributed to uneven degradation and distribution of crystalline and amorphous regions. Specifically, the disappearance of amorphous chains between fibrils at 6 months leads to mechanical failure. Further disappearance of amorphous chains within fibrils at 18 months results in structural disintegration. Additionally, the degradation behavior of the stents and potential effects of degradation products on vascular tissues are validated for predictive accuracy. These insights provide valuable experimental references for optimizing design and clinical application of PLLA-based self-expanding stents.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111044"},"PeriodicalIF":6.3,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572272","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 : 2024-10-22DOI: 10.1016/j.polymdegradstab.2024.111051
Sohail Yasin , Jianfeng Shi , Sheng Ye , Song Yihu , Aman Ullah , Guangzhong Li , Wenzhu Peng , Chaohua Gu
Additives play a crucial role in modifying and enhancing the properties of rubbers, improving mechanical strength, thermal stability, and chemical resistance to make them more suitable for various applications. The rubber industry faces challenges related to high resource consumption and toxic emissions, which are further impacted by the use of performance-enhancing additives. In hydrogen storage systems, tailored additives are required for rubbers to withstand elevated temperatures and high pressures, preventing hydrogen-induced swelling, a major cause of sealing failure. Herein, a novel form of carbonaceous material, carbon nano-onions (CNOs), and the bio-based plasticizer additive epoxidized soybean oil (ESO) are utilized in conventional silica-filled nitrile butadiene rubber (NBR) nanocomposites to develop low-carbon manufacturing high pressure hydrogen resistant O-rings for sealing applications. The results reveal that the incorporation of CNOs increases the crosslinking density (vc), assisted by ESO, in silica-filled NBR nanocomposites. While the conventional adipate-based plasticizer and ESO were found to be susceptible to high pressure hydrogen exposures, ESO demonstrated sustained compressive sealing properties with increase in von-Mises stress and in elevated thermo-oxidative conditions over time. The results of the life cycle assessment (LCA) recommend ESO for low-carbon manufacturing in rubber processing over conventional plasticizer.
{"title":"Sustainable rubber nanocomposites for hydrogen sealings: Impact of carbon nano-onions and bio-based plasticizer","authors":"Sohail Yasin , Jianfeng Shi , Sheng Ye , Song Yihu , Aman Ullah , Guangzhong Li , Wenzhu Peng , Chaohua Gu","doi":"10.1016/j.polymdegradstab.2024.111051","DOIUrl":"10.1016/j.polymdegradstab.2024.111051","url":null,"abstract":"<div><div>Additives play a crucial role in modifying and enhancing the properties of rubbers, improving mechanical strength, thermal stability, and chemical resistance to make them more suitable for various applications. The rubber industry faces challenges related to high resource consumption and toxic emissions, which are further impacted by the use of performance-enhancing additives. In hydrogen storage systems, tailored additives are required for rubbers to withstand elevated temperatures and high pressures, preventing hydrogen-induced swelling, a major cause of sealing failure. Herein, a novel form of carbonaceous material, carbon nano-onions (CNOs), and the bio-based plasticizer additive epoxidized soybean oil (ESO) are utilized in conventional silica-filled nitrile butadiene rubber (NBR) nanocomposites to develop low-carbon manufacturing high pressure hydrogen resistant O-rings for sealing applications. The results reveal that the incorporation of CNOs increases the crosslinking density (<em>v</em><sub>c</sub>), assisted by ESO, in silica-filled NBR nanocomposites. While the conventional adipate-based plasticizer and ESO were found to be susceptible to high pressure hydrogen exposures, ESO demonstrated sustained compressive sealing properties with increase in von-Mises stress and in elevated thermo-oxidative conditions over time. The results of the life cycle assessment (LCA) recommend ESO for low-carbon manufacturing in rubber processing over conventional plasticizer.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111051"},"PeriodicalIF":6.3,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554153","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}
The aim of this work was to evaluate the functional properties of a family of poly(ester amide)s (PEAs) for flexible food packaging applications. The polymers under study were previously synthesized via random copolymerization of furan 2,5-dicarboxylic acid (2,5-FDCA) with different amounts of 1,10-decanediol and an amido diol (AD 46). Poly(decamethylene furanoate) (PDF) and poly(ester amide) 46 (PEA 46) were the reference homopolymers. PEA copolymers were compression molded into films and subjected to WAXS, DSC, SEM analyses and water contact angle, mechanical, gas barrier tests. The results showed a remarkable improvement in the functional properties of PEAs compared to those of PDF, with a decrease up to about 50% of O2 and CO2 transmission rates, which were found to be comparable to those of commercial PET. The mechanical properties of PEAs were also improved in comparison with PDF because of the increased toughness and higher resistance to plastic deformation, paired with elongation at break up to 650%. In order to assess the effects of contact with food, the prepared films were treated with food simulants. Moreover, the films were stored in conditions of controlled temperature and humidity, chosen to replicate real scenarios of application involving aggressive environmental conditions. After contact with food simulant liquids, the materials became more rigid and less ductile, but their gas barrier properties remained superior to those of commercially widespread polyolefins. Finally, films were subjected to composting tests: the higher the amido diol content, the faster the degradation rate, which occurred via a mechanism of bulk hydrolysis, because of the higher hydrophilicity of amide groups. Overall, the results highlighted the potential of PEA copolymers for the production of biobased, sustainable, flexible food packaging.
这项研究的目的是评估用于食品软包装的一系列聚（酯酰胺）（PEAs）的功能特性。所研究的聚合物是以前通过 2,5-呋喃二甲酸（2,5-FDCA）与不同量的 1,10-癸二醇和氨基二醇（AD 46）无规共聚合合成的。聚(呋喃十甲酸)(PDF)和聚(酯酰胺)46 (PEA 46) 是参照均聚物。PEA 共聚物被压缩成型为薄膜，并进行了 WAXS、DSC、SEM 分析以及水接触角、机械和气体阻隔性测试。结果表明，与 PDF 相比，PEA 的功能特性有了明显改善，氧气和二氧化碳透过率降低了约 50%，与商用 PET 不相上下。与 PDF 相比，PEA 的机械性能也有所改善，因为其韧性增强，抗塑性变形能力提高，断裂伸长率高达 650%。为了评估与食品接触的影响，用食品模拟物对制备的薄膜进行了处理。此外，还将薄膜储存在温度和湿度受控的条件下，以复制涉及侵蚀性环境条件的实际应用场景。与食品模拟液体接触后，材料变得更加坚硬，延展性降低，但其气体阻隔性能仍然优于市场上广泛使用的聚烯烃。最后，对薄膜进行了堆肥试验：酰胺二醇含量越高，降解速度越快，由于酰胺基团的亲水性较强，降解是通过大量水解的机制进行的。总之，研究结果凸显了 PEA 共聚物在生产生物基、可持续、柔性食品包装方面的潜力。
{"title":"Mechanical properties, gas permeability and biodegradation mechanism of biobased poly(ester amide)s from 2,5-furandicarboxylic acid and amido diols for sustainable food packaging","authors":"Enrico Bianchi , Lazaros Papadopoulos , Michelina Soccio , Valentina Siracusa , Massimo Gazzano , Tobias Robert , Dimitrios N. Bikiaris , Nadia Lotti","doi":"10.1016/j.polymdegradstab.2024.111049","DOIUrl":"10.1016/j.polymdegradstab.2024.111049","url":null,"abstract":"<div><div>The aim of this work was to evaluate the functional properties of a family of poly(ester amide)s (PEAs) for flexible food packaging applications. The polymers under study were previously synthesized via random copolymerization of furan 2,5-dicarboxylic acid (2,5-FDCA) with different amounts of 1,10-decanediol and an amido diol (AD 46). Poly(decamethylene furanoate) (PDF) and poly(ester amide) 46 (PEA 46) were the reference homopolymers. PEA copolymers were compression molded into films and subjected to WAXS, DSC, SEM analyses and water contact angle, mechanical, gas barrier tests. The results showed a remarkable improvement in the functional properties of PEAs compared to those of PDF, with a decrease up to about 50% of O<sub>2</sub> and CO<sub>2</sub> transmission rates, which were found to be comparable to those of commercial PET. The mechanical properties of PEAs were also improved in comparison with PDF because of the increased toughness and higher resistance to plastic deformation, paired with elongation at break up to 650%. In order to assess the effects of contact with food, the prepared films were treated with food simulants. Moreover, the films were stored in conditions of controlled temperature and humidity, chosen to replicate real scenarios of application involving aggressive environmental conditions. After contact with food simulant liquids, the materials became more rigid and less ductile, but their gas barrier properties remained superior to those of commercially widespread polyolefins. Finally, films were subjected to composting tests: the higher the amido diol content, the faster the degradation rate, which occurred via a mechanism of bulk hydrolysis, because of the higher hydrophilicity of amide groups. Overall, the results highlighted the potential of PEA copolymers for the production of biobased, sustainable, flexible food packaging.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111049"},"PeriodicalIF":6.3,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142538132","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 : 2024-10-20DOI: 10.1016/j.polymdegradstab.2024.111048
Hiroto Tada , Ikuo Taniguchi
An aliphatic polyether/carbonate block copolymer, comprising poly(1,5-dioxepan-2-one) (PDXO, glass transition temperature Tg: -38 °C) and poly(L-lactide) (PLLA, Tg: 55 °C), evinces remarkable formability under pressure at temperatures significantly below the melting point of PLLA. A quantitative and detailed evaluation of the low-temperature molding of the block copolymer was conducted using a capillary rheometer. The findings reveal that block copolymers with PDXO composition >55 wt% demonstrate a propensity to flow at room temperature under 50 MPa pressure. Consequently, the practice of low-temperature molding serves to mitigate the degradation of polymer chains during the molding process, thereby augmenting recyclability. Furthermore, the enzymatic degradability of the block copolymer was extensively investigated using lipase PS and proteinase K. An interplay between the structure of the block copolymer and the degradation kinetics was explored. The polymeric materials developed, possessing both pressure formability and degradability, hold promising potential as environmentally benign polymers with reduced environmental impact.
{"title":"Pressure-induced formability and degradability of block copolymers composed of poly(1,5-dioxepan-2-one) and poly(L-lactide)","authors":"Hiroto Tada , Ikuo Taniguchi","doi":"10.1016/j.polymdegradstab.2024.111048","DOIUrl":"10.1016/j.polymdegradstab.2024.111048","url":null,"abstract":"<div><div>An aliphatic polyether/carbonate block copolymer, comprising poly(1,5-dioxepan-2-one) (PDXO, glass transition temperature <em>T</em><sub>g</sub>: -38 °C) and poly(L-lactide) (PLLA, <em>T</em><sub>g</sub>: 55 °C), evinces remarkable formability under pressure at temperatures significantly below the melting point of PLLA. A quantitative and detailed evaluation of the low-temperature molding of the block copolymer was conducted using a capillary rheometer. The findings reveal that block copolymers with PDXO composition >55 wt% demonstrate a propensity to flow at room temperature under 50 MPa pressure. Consequently, the practice of low-temperature molding serves to mitigate the degradation of polymer chains during the molding process, thereby augmenting recyclability. Furthermore, the enzymatic degradability of the block copolymer was extensively investigated using lipase PS and proteinase K. An interplay between the structure of the block copolymer and the degradation kinetics was explored. The polymeric materials developed, possessing both pressure formability and degradability, hold promising potential as environmentally benign polymers with reduced environmental impact.</div></div>","PeriodicalId":406,"journal":{"name":"Polymer Degradation and Stability","volume":"230 ","pages":"Article 111048"},"PeriodicalIF":6.3,"publicationDate":"2024-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554152","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}
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