Pub Date : 2024-11-20DOI: 10.1016/j.polymer.2024.127869
Yasser Zare, Muhammad Tajammal Munir, Kyong Yop Rhee, Soo-Jin Park
Current modeling approaches for the conductivity of polymer composites containing carbon nanofiber (CNF) called as PCNFs exhibit limitations. Herein, we introduce an enhanced Ouali model to accurately forecast the PCNF conductivity by incorporating the operative CNF amount and the conductivity contributions of CNFs, interphase region, and tunneling zones. The effective CNF volume fraction is derived from the dimensions of both CNFs and interphase, while the overall conductivity calculation integrates the resistances of interphase region and tunnels. The model's accuracy is validated through empirical conductivity measurements of various PCNF samples and extensive parametric analyses. An interphase depth (t) of less than 8 nm renders the composite insulative, whereas peak conductivity of 0.04 S/m is achieved at an interphase depth of 40 nm and interphase conductivity of 400 S/m. These results underscore the significant influence of interphase depth and conductivity on the overall electrical performance of the composites. Furthermore, a CNF length (l) below 13 μm or a contact diameter (d) under 10 nm also results in an insulative composite. Conversely, maximum values of CNF length (80 μm) and contact diameter (40 nm) enhance the composite's conductivity to 0.1 S/m. These findings illustrate the advantageous impact of longer nanofibers and wider tunnels on the electrical conductivity of PCNFs.
{"title":"A New Method for Conductivity Prediction in Polymer Carbon Nanofiber System by the Interphase Size and Total Conductivity of Constituents","authors":"Yasser Zare, Muhammad Tajammal Munir, Kyong Yop Rhee, Soo-Jin Park","doi":"10.1016/j.polymer.2024.127869","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127869","url":null,"abstract":"Current modeling approaches for the conductivity of polymer composites containing carbon nanofiber (CNF) called as PCNFs exhibit limitations. Herein, we introduce an enhanced Ouali model to accurately forecast the PCNF conductivity by incorporating the operative CNF amount and the conductivity contributions of CNFs, interphase region, and tunneling zones. The effective CNF volume fraction is derived from the dimensions of both CNFs and interphase, while the overall conductivity calculation integrates the resistances of interphase region and tunnels. The model's accuracy is validated through empirical conductivity measurements of various PCNF samples and extensive parametric analyses. An interphase depth (<em>t</em>) of less than 8 nm renders the composite insulative, whereas peak conductivity of 0.04 S/m is achieved at an interphase depth of 40 nm and interphase conductivity of 400 S/m. These results underscore the significant influence of interphase depth and conductivity on the overall electrical performance of the composites. Furthermore, a CNF length (<em>l</em>) below 13 μm or a contact diameter (<em>d</em>) under 10 nm also results in an insulative composite. Conversely, maximum values of CNF length (80 μm) and contact diameter (40 nm) enhance the composite's conductivity to 0.1 S/m. These findings illustrate the advantageous impact of longer nanofibers and wider tunnels on the electrical conductivity of PCNFs.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"11 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678675","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 : 2024-11-19DOI: 10.1016/j.polymer.2024.127865
Muhammad Ateeq, Arslan Akbar, Muhammad Shafique
Carbon fiber-reinforced polymer composites are widely used for their corrosion resistance, high strength, stiffness, and lightweight properties. However, the extensive use of carbon fiber generates significant waste at the end of its lifecycle. Recycling technologies can effectively recover carbon fiber from this waste, making it suitable for reuse in various applications. Recently, there has been a growing trend in using recycled carbon fiber as a reinforcement material in polymer matrices, offering a cost-effective alternative to virgin carbon fiber while maintaining excellent mechanical properties. However, most studies focus on the mechanical strength of parts made from recycled and virgin carbon fibers, with less attention given to the environmental impacts of these materials. The primary objective of this study is the comparative analysis of the specimens manufactured using recycled and virgin carbon fiber-reinforced polyamide-12 material based on the mechanical performance, life cycle cost, and environmental impact. The experimental investigations showed that the mechanical performance of the recycled carbon fiber polyamide-12 (rCFRP12) composites are more efficient than the specimens manufactured using the virgin carbon fiber polyamide-12 (vCFRP12) composites such as three-point bending test results show that parts made from rCFRP12 composites achieved a flexural strength of 56.25 MPa, outperforming those made with vCFRP12 (49.9 MPa). Additionally, the recycled composite specimens also exhibited higher tensile strength than their virgin carbon fiber counterparts. The life cycle analysis revealed that samples made with recycled carbon fiber have a lower environmental impact, reducing global warming, ozone depletion, and carcinogenic effects by 11.98% compared to those made with virgin carbon fiber. Additionally, the production cost of recycled carbon fiber is significantly lower than that of virgin carbon fiber.
{"title":"Advancing Circular Economy: Comparative Analysis of Recycled and Virgin Carbon Fiber 3D Printed Composites on Performance and Eco-Efficiency","authors":"Muhammad Ateeq, Arslan Akbar, Muhammad Shafique","doi":"10.1016/j.polymer.2024.127865","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127865","url":null,"abstract":"Carbon fiber-reinforced polymer composites are widely used for their corrosion resistance, high strength, stiffness, and lightweight properties. However, the extensive use of carbon fiber generates significant waste at the end of its lifecycle. Recycling technologies can effectively recover carbon fiber from this waste, making it suitable for reuse in various applications. Recently, there has been a growing trend in using recycled carbon fiber as a reinforcement material in polymer matrices, offering a cost-effective alternative to virgin carbon fiber while maintaining excellent mechanical properties. However, most studies focus on the mechanical strength of parts made from recycled and virgin carbon fibers, with less attention given to the environmental impacts of these materials. The primary objective of this study is the comparative analysis of the specimens manufactured using recycled and virgin carbon fiber-reinforced polyamide-12 material based on the mechanical performance, life cycle cost, and environmental impact. The experimental investigations showed that the mechanical performance of the recycled carbon fiber polyamide-12 (rCFRP12) composites are more efficient than the specimens manufactured using the virgin carbon fiber polyamide-12 (vCFRP12) composites such as three-point bending test results show that parts made from rCFRP12 composites achieved a flexural strength of 56.25 MPa, outperforming those made with vCFRP12 (49.9 MPa). Additionally, the recycled composite specimens also exhibited higher tensile strength than their virgin carbon fiber counterparts. The life cycle analysis revealed that samples made with recycled carbon fiber have a lower environmental impact, reducing global warming, ozone depletion, and carcinogenic effects by 11.98% compared to those made with virgin carbon fiber. Additionally, the production cost of recycled carbon fiber is significantly lower than that of virgin carbon fiber.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"54 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671048","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 : 2024-11-19DOI: 10.1016/j.polymer.2024.127860
Elli Bellou, Anastasios C. Manikas, Maria Giovanna Pastore Carbone, Stella Peloni, Christos Tsakonas, Costas Galiotis
Failure of polymers frequently initiates at discontinuities in the material, such as holes and notches, as they constitute points of increased stress concentration. Herein, we propose the use of monolayer graphene produced via Chemical Vapour Deposition to monitor the stress distribution close to a defect in poly(methyl methacrylate). Combining in-situ Raman spectroscopic mapping with tensile tests, the stress/strain distribution around the defect can be probed via monitoring the wavenumber shift of the spectroscopic features of graphene. The measured stress concentration factor of 2.41 is remarkably close to the value derived from Finite Element Analysis, and agrees with other studies in the literature, thus demonstrating that the proposed technique is reliable, and that graphene can accurately sense stress concentration close to a defect, with a sub-micron spatial resolution and a strain resolution of ≈ 60 με.
{"title":"Monitoring stress concentration in polymers with circular notch exploiting graphene-based sensors","authors":"Elli Bellou, Anastasios C. Manikas, Maria Giovanna Pastore Carbone, Stella Peloni, Christos Tsakonas, Costas Galiotis","doi":"10.1016/j.polymer.2024.127860","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127860","url":null,"abstract":"Failure of polymers frequently initiates at discontinuities in the material, such as holes and notches, as they constitute points of increased stress concentration. Herein, we propose the use of monolayer graphene produced via Chemical Vapour Deposition to monitor the stress distribution close to a defect in poly(methyl methacrylate). Combining in-situ Raman spectroscopic mapping with tensile tests, the stress/strain distribution around the defect can be probed via monitoring the wavenumber shift of the spectroscopic features of graphene. The measured stress concentration factor of 2.41 is remarkably close to the value derived from Finite Element Analysis, and agrees with other studies in the literature, thus demonstrating that the proposed technique is reliable, and that graphene can accurately sense stress concentration close to a defect, with a sub-micron spatial resolution and a strain resolution of ≈ 60 με.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"69 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671050","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}
High-performance epoxy materials often necessitate curing at high-temperature, which can lead to defects, brittleness, deformation and processing difficulties. In this paper, the modifier sulfhydryl hyperbranched polysiloxane (HSiSH) was fabricated by the “one-pot” method. And investigated the effect of HSiSH on the curing temperature, mechanical and thermal properties of epoxy resin. The epoxy with the addition of 2.0 wt% HSiSH showcased superior comprehensive properties, including flexural strength of 159.37 MPa, impact strength of 24.77 kJ/m2, and tensile shear strength of 14.02 MPa, as well as the thermal properties are improved. Moreover, the presence of 2 wt% HSiSH can facilitate the curing process reducing the apparent activation energy by 12.25%. The highly branched topology, chain entanglement, "rigid-flexible" -Si-O-C- segment and active groups improve the strength and toughness of the material. Simultaneously, the numerous reactive groups within HSiSH actively participate in the curing reaction, thereby enhancing the adhesion between the resin and the substrate surface which increasing the bonding performance of the adhesive. This study lays a solid theoretical foundation for developing high-performance epoxy resins cured at lower and moderate temperatures.
{"title":"Epoxy resins containing sulfhydryl hyperbranched polysiloxane with desirable mechanical properties and lower curing temperature","authors":"Feifei Wang, Junyan Yao, Kaiming Yang, Bingrui Shi, Zhenlong Zhang, Weixu Feng, Hongxia Yan","doi":"10.1016/j.polymer.2024.127859","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127859","url":null,"abstract":"High-performance epoxy materials often necessitate curing at high-temperature, which can lead to defects, brittleness, deformation and processing difficulties. In this paper, the modifier sulfhydryl hyperbranched polysiloxane (HSiSH) was fabricated by the “one-pot” method. And investigated the effect of HSiSH on the curing temperature, mechanical and thermal properties of epoxy resin. The epoxy with the addition of 2.0 wt% HSiSH showcased superior comprehensive properties, including flexural strength of 159.37 MPa, impact strength of 24.77 kJ/m<sup>2</sup>, and tensile shear strength of 14.02 MPa, as well as the thermal properties are improved. Moreover, the presence of 2 wt% HSiSH can facilitate the curing process reducing the apparent activation energy by 12.25%. The highly branched topology, chain entanglement, \"rigid-flexible\" -Si-O-C- segment and active groups improve the strength and toughness of the material. Simultaneously, the numerous reactive groups within HSiSH actively participate in the curing reaction, thereby enhancing the adhesion between the resin and the substrate surface which increasing the bonding performance of the adhesive. This study lays a solid theoretical foundation for developing high-performance epoxy resins cured at lower and moderate temperatures.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"99 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670811","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}
This study investigates the flexural strength of 3D-printed nylon-carbon reinforced composite specimens, highlighting the impact of infill density and layer height on mechanical performance. The findings indicate that a printing layer height of 0.10 mm with 100% infill density exhibits the highest flexural strength, supporting a maximum load of 127 N, compared to 76.7 N at 50% infill density. Microstructural study has clearly illustrated the structural distortion, revealing that a rise in layer height correlates with an escalation in structural distortion. An Artificial Neural Network (ANN) model is thus utilized to achieve high predictive accuracy in order to predict flexural behaviour. R-values above 0.98 are obtained across training, validation, and test datasets, indicating that ANN-based modelling may be able to facilitate quick optimization of 3D printing parameters for high-performance applications. These findings establish carbon-reinforced nylon as a formidable competitor for use in industries such as aerospace and automotive, where strength and durability are important.
本研究调查了三维打印尼龙-碳增强复合材料试样的抗弯强度，突出了填充密度和层高对机械性能的影响。研究结果表明，打印层高为 0.10 毫米、填充密度为 100% 的试样具有最高的抗弯强度，可承受 127 牛顿的最大载荷，而填充密度为 50% 的试样仅能承受 76.7 牛顿的载荷。微观结构研究清楚地表明了结构的变形，揭示了层高的增加与结构变形的升级相关。因此，利用人工神经网络（ANN）模型实现了高预测精度，以预测弯曲行为。训练、验证和测试数据集的 R 值均高于 0.98，这表明基于 ANN 的建模可能有助于快速优化高性能应用的 3D 打印参数。这些研究结果确立了碳增强尼龙在航空航天和汽车等对强度和耐用性要求较高的行业中的强大竞争力。
{"title":"Evaluation of Flexural strength of 3D-Printed Nylon with carbon reinforcement: An experimental validation using ANN","authors":"Vijay Kumar, Dhinakaran Veeman, Murugan Vellaisamy, Vikrant Singh","doi":"10.1016/j.polymer.2024.127854","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127854","url":null,"abstract":"This study investigates the flexural strength of 3D-printed nylon-carbon reinforced composite specimens, highlighting the impact of infill density and layer height on mechanical performance. The findings indicate that a printing layer height of 0.10 mm with 100% infill density exhibits the highest flexural strength, supporting a maximum load of 127 N, compared to 76.7 N at 50% infill density. Microstructural study has clearly illustrated the structural distortion, revealing that a rise in layer height correlates with an escalation in structural distortion. An Artificial Neural Network (ANN) model is thus utilized to achieve high predictive accuracy in order to predict flexural behaviour. R-values above 0.98 are obtained across training, validation, and test datasets, indicating that ANN-based modelling may be able to facilitate quick optimization of 3D printing parameters for high-performance applications. These findings establish carbon-reinforced nylon as a formidable competitor for use in industries such as aerospace and automotive, where strength and durability are important.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"22 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142671049","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}
N-bromosuccinimide (NBS) has notable selectivity for brominating aromatic compounds with alkyl side chains. This study employs NBS in lieu of liquid bromine to prepare spinnable isotropic pitch derived from ethylene tar pitch (ETP) using a selective photobromination-debromination approach. The prepared isotropic pitches were then utilized to fabricate isotropic pitch-based carbon fibers (IPCFs) through a process involving melt spinning, oxidative stabilization, and subsequent carbonization. As the amount of NBS added increases in the photobromination stage, the softening point, pitch yield, average molecular weight, and degree of polymerization of the resulting isotropic pitch gradually increase, whereas its spinnability first improves but then decreases. Compared with the isotropic pitch manufactured through thermal polymerization alone, the isotropic pitch that undergo photobromination–debromination exhibits a more linear molecular structure formed by methylene/ethylidene-bridged aromatic units. This molecular structure enhances its spinnability, significantly improving the mechanical performance of the resulting IPCFs. The isotropic pitch produced with 15 wt% NBS during photobromination demonstrates exceptional spinnability, yielding carbon fibers with excellent mechanical characteristics. These fibers exhibit a tensile strength of 1333 MPa, Young’s modulus of 64 GPa, and an elongation property of 2.4%. This work provides a new method for the high value-added utilization of ET by controlling the molecular structure of the pitch precursor.
{"title":"Controllable preparation of spinnable isotropic pitches for carbon fibers with high tensile strength from low-cost ethylene tar pitch by a selective photobromination–debromination method","authors":"Ganggang Zhai, Jianguang Guo, Yongsheng Tian, Guanming Yuan, Ye Cong, Baoliu Li, Qin Zhang, Yongting Chen, Xuanke Li, Zhijun Dong","doi":"10.1016/j.polymer.2024.127862","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127862","url":null,"abstract":"N-bromosuccinimide (NBS) has notable selectivity for brominating aromatic compounds with alkyl side chains. This study employs NBS in lieu of liquid bromine to prepare spinnable isotropic pitch derived from ethylene tar pitch (ETP) using a selective photobromination-debromination approach. The prepared isotropic pitches were then utilized to fabricate isotropic pitch-based carbon fibers (IPCFs) through a process involving melt spinning, oxidative stabilization, and subsequent carbonization. As the amount of NBS added increases in the photobromination stage, the softening point, pitch yield, average molecular weight, and degree of polymerization of the resulting isotropic pitch gradually increase, whereas its spinnability first improves but then decreases. Compared with the isotropic pitch manufactured through thermal polymerization alone, the isotropic pitch that undergo photobromination–debromination exhibits a more linear molecular structure formed by methylene/ethylidene-bridged aromatic units. This molecular structure enhances its spinnability, significantly improving the mechanical performance of the resulting IPCFs. The isotropic pitch produced with 15 wt% NBS during photobromination demonstrates exceptional spinnability, yielding carbon fibers with excellent mechanical characteristics. These fibers exhibit a tensile strength of 1333 MPa, Young’s modulus of 64 GPa, and an elongation property of 2.4%. This work provides a new method for the high value-added utilization of ET by controlling the molecular structure of the pitch precursor.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"2 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670982","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 : 2024-11-19DOI: 10.1016/j.polymer.2024.127864
Delia Mihaela Rata, Anca Niculina Cadinoiu, Leonard Ionut Atanase, Gabriela Vochita, Sverre Arne Sande, Marcel Popa
Conventional administration of drugs to the inner ear involves therapeutic instability and non-specificity of release, and to overcome these limitations, various drug delivery systems have been developed. The aim of this study was to prepare and characterize peptides-functionalized oligochitosan microcapsules loaded with Dexamethasone and magnetic nanoparticles, which can be used for dual active targeted treatment of inner ear inflammation. The diameter of spherical microcapsules in aqueous solutions was found in the micrometer range. In vitro dexamethasone release kinetics, capsules biodegradation, haemolysis and cellular viability on V79-4 normal cells were also investigated. The release efficiency of dexamethasone from the microcapsules was between 74% and 99.8% after 24 hours. Obtained results indicated that all analyzed microcapsules showed hemolysis degrees lower than 3%, which demonstrated their non-hemolytic character. The viability and morphology tests on V79-4 cells depended on the administered dose and after a 48-hour treatment, all analyzed capsules showed a non-toxic, weak or moderately cytotoxic effect.
{"title":"Peptide-functionalized magnetic microcapsules loaded with dexamethasone for dual active targeted treatment of inner ear inflammation","authors":"Delia Mihaela Rata, Anca Niculina Cadinoiu, Leonard Ionut Atanase, Gabriela Vochita, Sverre Arne Sande, Marcel Popa","doi":"10.1016/j.polymer.2024.127864","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127864","url":null,"abstract":"Conventional administration of drugs to the inner ear involves therapeutic instability and non-specificity of release, and to overcome these limitations, various drug delivery systems have been developed. The aim of this study was to prepare and characterize peptides-functionalized oligochitosan microcapsules loaded with Dexamethasone and magnetic nanoparticles, which can be used for dual active targeted treatment of inner ear inflammation. The diameter of spherical microcapsules in aqueous solutions was found in the micrometer range. <em>In vitro</em> dexamethasone release kinetics, capsules biodegradation, haemolysis and cellular viability on V79-4 normal cells were also investigated. The release efficiency of dexamethasone from the microcapsules was between 74% and 99.8% after 24 hours. Obtained results indicated that all analyzed microcapsules showed hemolysis degrees lower than 3%, which demonstrated their non-hemolytic character. The viability and morphology tests on V79-4 cells depended on the administered dose and after a 48-hour treatment, all analyzed capsules showed a non-toxic, weak or moderately cytotoxic effect.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"6 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673697","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 : 2024-11-19DOI: 10.1016/j.polymer.2024.127866
Yanwen Chen, Jianguo Xu, Miao Miao, Xueqin Shi, Nana Li
The ultrafiltration membrane serves to sieve macromolecules but is unable to eliminate heavy metal ions in water, and is prone to be polluted by macromolecules. To achieve the multifunctional and anti-fouling of polyvinylidene fluoride (PVDF) ultrafiltration membrane, we employed the chemical grafting method to synthesize carboxymethyl polyvinyl alcohol (CPVA). Subsequently, we blended CPVA with the PVDF membrane, employing the non-solvent co-induced phase separation (NIPS) method to fabricate the carboxymethylated PVA modified PVDF (CPVA/PVDF) ultrafiltration membrane, which demonstrated significant Cu(II) absorbance capability alongside anti-fouling properties. By observing the sieve-adsorption process, we observed a substantial enhancement in permeate flux, increasing from 1.21 L·m-2·h-1 for the pure PVDF membrane to 53.37 L·m-2·h-1 for the CPVA/PVDF membrane. The static adsorption of the ultrafiltration membrane satisfied the Langmuir and Freundlich isothermal models and followed pseudo-second-order kinetic model. Moreover, the blended membrane effectively removed Bovine Serum Albumin (BSA) and Cu(II) simultaneously, achieving BSA rejection efficiency of 92.00% and Cu(II) removal rate of 90.89%. After 10 cycles of sieving and adsorption, the BSA rejection efficiency remained consistently above 91.00%, while the initial Cu(II) removal rate exceeded 81.00%, indicating excellent reproducibility. In addition to the filtration of BSA, the blended membrane exhibited a low irreversible fouling of 2.59% and a high fouling recovery rate of 97.41%, underscoring its robust anti-fouling properties. The developed sieve-adsorption ultrafiltration membrane lays a solid foundation for the effective treatment of complex wastewater streams.
{"title":"Carboxymethylated PVA/PVDF ultrafiltration membrane for removing Cu(II) from water","authors":"Yanwen Chen, Jianguo Xu, Miao Miao, Xueqin Shi, Nana Li","doi":"10.1016/j.polymer.2024.127866","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127866","url":null,"abstract":"The ultrafiltration membrane serves to sieve macromolecules but is unable to eliminate heavy metal ions in water, and is prone to be polluted by macromolecules. To achieve the multifunctional and anti-fouling of polyvinylidene fluoride (PVDF) ultrafiltration membrane, we employed the chemical grafting method to synthesize carboxymethyl polyvinyl alcohol (CPVA). Subsequently, we blended CPVA with the PVDF membrane, employing the non-solvent co-induced phase separation (NIPS) method to fabricate the carboxymethylated PVA modified PVDF (CPVA/PVDF) ultrafiltration membrane, which demonstrated significant Cu(II) absorbance capability alongside anti-fouling properties. By observing the sieve-adsorption process, we observed a substantial enhancement in permeate flux, increasing from 1.21 L·m<sup>-2</sup>·h<sup>-1</sup> for the pure PVDF membrane to 53.37 L·m<sup>-2</sup>·h<sup>-1</sup> for the CPVA/PVDF membrane. The static adsorption of the ultrafiltration membrane satisfied the Langmuir and Freundlich isothermal models and followed pseudo-second-order kinetic model. Moreover, the blended membrane effectively removed Bovine Serum Albumin (BSA) and Cu(II) simultaneously, achieving BSA rejection efficiency of 92.00% and Cu(II) removal rate of 90.89%. After 10 cycles of sieving and adsorption, the BSA rejection efficiency remained consistently above 91.00%, while the initial Cu(II) removal rate exceeded 81.00%, indicating excellent reproducibility. In addition to the filtration of BSA, the blended membrane exhibited a low irreversible fouling of 2.59% and a high fouling recovery rate of 97.41%, underscoring its robust anti-fouling properties. The developed sieve-adsorption ultrafiltration membrane lays a solid foundation for the effective treatment of complex wastewater streams.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"63 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673609","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 polymer dispersity index (PDI) is a vital metric for characterizing molecular weight distribution, significantly influencing polymer material performance. However, achieving precise control over PDI in polymer synthesis remains a substantial challenge. In this study, we introduce an approach for modifying the PDI of poly(methyl acrylate) (PMA) in switchable reversible addition-fragmentation chain transfer radical polymerizations (RAFT). The devised strategy involves the utilization of photoresponsive hexaarylbiimidazole (HABI) as a mediator, coupled with temporal programming, to cyclically deactivate and reactivate propagating radicals at distinct stages throughout the polymerization process. The precise timing of the light stimulus is facilitated through computer-controlled single-chip microcomputer technology, ensuring automatic modulation of the optical state and mitigating operational inaccuracies. By manipulating external light conditions, the PDI of PMAs can be systematically adjusted within the range of 1.80 to 2.59. Validation through successful chain-extension experiments and analysis via MALDI-TOF MS confirm the preservation of good chain-end fidelity across PMAs with varying PDIs fabricated through this methodology.
{"title":"Control of Molecular Weight Distribution through Photoresponsive RAFT Polymerization with a Temporal Program-Controlled System","authors":"Jincheng Sui, Xiaoyu Miao, Xin Cao, Qiuyu Ding, Longqiang Xiao, Linxi Hou","doi":"10.1016/j.polymer.2024.127863","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127863","url":null,"abstract":"The polymer dispersity index (PDI) is a vital metric for characterizing molecular weight distribution, significantly influencing polymer material performance. However, achieving precise control over PDI in polymer synthesis remains a substantial challenge. In this study, we introduce an approach for modifying the PDI of poly(methyl acrylate) (PMA) in switchable reversible addition-fragmentation chain transfer radical polymerizations (RAFT). The devised strategy involves the utilization of photoresponsive hexaarylbiimidazole (HABI) as a mediator, coupled with temporal programming, to cyclically deactivate and reactivate propagating radicals at distinct stages throughout the polymerization process. The precise timing of the light stimulus is facilitated through computer-controlled single-chip microcomputer technology, ensuring automatic modulation of the optical state and mitigating operational inaccuracies. By manipulating external light conditions, the PDI of PMAs can be systematically adjusted within the range of 1.80 to 2.59. Validation through successful chain-extension experiments and analysis <em>via</em> MALDI-TOF MS confirm the preservation of good chain-end fidelity across PMAs with varying PDIs fabricated through this methodology.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"55 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142670810","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 : 2024-11-17DOI: 10.1016/j.polymer.2024.127817
Jordan Varma, Isha Farook, Jianxun Cui, Eva Morgenthaler, Caitlin Bien, Tiffany Yu, Dorin Preda, W. John Kidd, David Gamliel, Todd Emrick
We describe the fabrication of biopolymer foams formed from aqueous solutions of hydroxypropyl cellulose, whereby freezing-induced phase-separation and solvent removal yields robust foam structures that are elastic in air and when wet, and that are stable to repeated compression when fully saturated with water. Through mechanisms of phase-separation, pore formation, and covalent crosslinking, we discovered effective methods to prepare microporous HPC foams that resist gelation even when exposed to water for long time frames (at least months). Employing multifunctional carboxylic acid crosslinkers allowed the foams to maintain their integrity when dry or wet, while the presence of α-cellulose as an additive further augmented their mechanical integrity and provided a means to adjust elasticity. The amount of crosslinker employed in the foaming process significantly impacted foam stability and water uptake, while polymeric crosslinkers enabled insertion of sulfobetaine zwitterionic moieties into the foams. Notably, the thermal transition characteristic of HPC solutions and gels proved operative in foam form, as seen in release of water from a saturated HPC foam using a combination of compressive and thermal mechanisms.
{"title":"Biopolymer Foams Composed of Hydroxypropyl Cellulose: Fabrication, Aqueous Stability, and Mechanical Integrity","authors":"Jordan Varma, Isha Farook, Jianxun Cui, Eva Morgenthaler, Caitlin Bien, Tiffany Yu, Dorin Preda, W. John Kidd, David Gamliel, Todd Emrick","doi":"10.1016/j.polymer.2024.127817","DOIUrl":"https://doi.org/10.1016/j.polymer.2024.127817","url":null,"abstract":"We describe the fabrication of biopolymer foams formed from aqueous solutions of hydroxypropyl cellulose, whereby freezing-induced phase-separation and solvent removal yields robust foam structures that are elastic in air and when wet, and that are stable to repeated compression when fully saturated with water. Through mechanisms of phase-separation, pore formation, and covalent crosslinking, we discovered effective methods to prepare microporous HPC foams that resist gelation even when exposed to water for long time frames (at least months). Employing multifunctional carboxylic acid crosslinkers allowed the foams to maintain their integrity when dry or wet, while the presence of α-cellulose as an additive further augmented their mechanical integrity and provided a means to adjust elasticity. The amount of crosslinker employed in the foaming process significantly impacted foam stability and water uptake, while polymeric crosslinkers enabled insertion of sulfobetaine zwitterionic moieties into the foams. Notably, the thermal transition characteristic of HPC solutions and gels proved operative in foam form, as seen in release of water from a saturated HPC foam using a combination of compressive and thermal mechanisms.","PeriodicalId":405,"journal":{"name":"Polymer","volume":"169 1","pages":""},"PeriodicalIF":4.6,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665546","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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