Chaoen Jin, Lei Wang, Huamei Zhu, Fan Wang, Yaping Zhu, Huimin Qi
Silicon‐containing arylacetylene resin (PSA)‐matrix composites hold great potential for aerospace applications due to their excellent heat resistance. In recent years, many PSAs with specific functions have been designed via materials genome approach (MGA), and appropriate resin transfer molding (RTM) curing processes need to be screened to strike a balance between low cost and high quality. In this study, a novel tool based on finite element curing simulation and multiobjective genetic algorithm was developed to optimize the RTM curing process for novel PSA‐matrix composites. The silicon‐containing fluorenylacetylene resin (PSA‐VBF) was selected as the object to systematically characterize its apparent curing kinetics. To address the problem of explosive polymerization of the resin at the injection port during the RTM process, a multiobjective optimization of the curing process using a genetic algorithm was performed to obtain the Pareto front with the maximum temperature gradient at the injection port of the resin, the maximum degree of cure gradient of the composites, and the process time as the objectives. A global sensitivity analysis was also conducted to identify the key parameters. The results demonstrate that the optimized curing process can significantly reduce the temperature gradient and the curing degree gradient with improved curing efficiency.
{"title":"Multiobjective optimization of resin transfer molding curing process for silicon‐containing arylacetylene resin‐matrix composites","authors":"Chaoen Jin, Lei Wang, Huamei Zhu, Fan Wang, Yaping Zhu, Huimin Qi","doi":"10.1002/pat.6586","DOIUrl":"https://doi.org/10.1002/pat.6586","url":null,"abstract":"Silicon‐containing arylacetylene resin (PSA)‐matrix composites hold great potential for aerospace applications due to their excellent heat resistance. In recent years, many PSAs with specific functions have been designed via materials genome approach (MGA), and appropriate resin transfer molding (RTM) curing processes need to be screened to strike a balance between low cost and high quality. In this study, a novel tool based on finite element curing simulation and multiobjective genetic algorithm was developed to optimize the RTM curing process for novel PSA‐matrix composites. The silicon‐containing fluorenylacetylene resin (PSA‐VBF) was selected as the object to systematically characterize its apparent curing kinetics. To address the problem of explosive polymerization of the resin at the injection port during the RTM process, a multiobjective optimization of the curing process using a genetic algorithm was performed to obtain the Pareto front with the maximum temperature gradient at the injection port of the resin, the maximum degree of cure gradient of the composites, and the process time as the objectives. A global sensitivity analysis was also conducted to identify the key parameters. The results demonstrate that the optimized curing process can significantly reduce the temperature gradient and the curing degree gradient with improved curing efficiency.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"17 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Superhydrophobic coatings have been used to solve the problems of oil spills polluting water sources and water resource shortages. However, the short service life of superhydrophobic coatings limit their widely application. In this work, a novel fluorine‐free, self‐healing, and superhydrophobic coating composing of polydimethylsiloxane (PDMS), polydopamine (PDA) modified halloysite nanotubes (HNT), and beeswax (BW) are fabricated for oil/water separation as well as fog‐water collection. Herein, PDA stabilizes the dispersion of HNT in the coating, and meanwhile enhances the adhesion of modified nanoparticles on fabric surfaces. The as‐fabricated coatings occupied a water contact angle of 163.1°, demonstrating exceptional superhydrophobic characteristics. The superhydrophobic coating exhibited superior oil/water separation efficiency of over 99.5% and outstanding fog‐water collection rate of 990 ~ 1208 mg cm−2 h−1. Owing to the presence of BW, the coatings demonstrated remarkable self‐healing properties and can regain superhydrophobicity after 100 wear cycles with just a short heating treatment. Therefore, this facile strategy has great potential for large‐scale manufacturing of multifunctional superhydrophobic coatings.
{"title":"Fluorine‐free, self‐healing, and superhydrophobic coating for efficient oil/water separation and fog‐water collection","authors":"Yuzhu Hu, Meng Zhou, Xinya Zhang, Heqing Fu","doi":"10.1002/pat.6584","DOIUrl":"https://doi.org/10.1002/pat.6584","url":null,"abstract":"Superhydrophobic coatings have been used to solve the problems of oil spills polluting water sources and water resource shortages. However, the short service life of superhydrophobic coatings limit their widely application. In this work, a novel fluorine‐free, self‐healing, and superhydrophobic coating composing of polydimethylsiloxane (PDMS), polydopamine (PDA) modified halloysite nanotubes (HNT), and beeswax (BW) are fabricated for oil/water separation as well as fog‐water collection. Herein, PDA stabilizes the dispersion of HNT in the coating, and meanwhile enhances the adhesion of modified nanoparticles on fabric surfaces. The as‐fabricated coatings occupied a water contact angle of 163.1°, demonstrating exceptional superhydrophobic characteristics. The superhydrophobic coating exhibited superior oil/water separation efficiency of over 99.5% and outstanding fog‐water collection rate of 990 ~ 1208 mg cm<jats:sup>−2</jats:sup> h<jats:sup>−1</jats:sup>. Owing to the presence of BW, the coatings demonstrated remarkable self‐healing properties and can regain superhydrophobicity after 100 wear cycles with just a short heating treatment. Therefore, this facile strategy has great potential for large‐scale manufacturing of multifunctional superhydrophobic coatings.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"78 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142257003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aiming at achieving low‐frequency and broadband sound absorption under the premise of light and thin layers, in this paper, polyvinyl butyral (PVB) nanofiber membranes were micro‐perforated and then combined sequentially to prepare multi‐layer micro‐perforated nanofiber membrane (MPNM) for acoustic noise reduction. It was demonstrated that the multi‐layer MPNM exhibited a high absorption (constantly over 50%) in the frequency of 480–2500 Hz. In addition, the established theoretical model of the sound absorbing coefficient can accurately predict the sound absorption performance of the structure with different layers, which can provide a theoretical foundation for the design of the structure of the nanofibrous membrane acoustic absorber. Based on the proposed acoustic model, the relationships between the absorption properties and the parameters were investigated, and it was found that the effective acoustic absorption frequency range and acoustic absorption coefficient curve of the multi‐layer MPNM were closely related to the size and arrangement of hole diameter, perforation rate, fiber membrane thickness, and cavity depth. Optimization of the structural parameters utilizing algorithms can achieve superior sound absorption performance, with an average absorption coefficient of 0.81 in the frequency of 100–2500 Hz. This study provides a theoretical and experimental basis for the development of low‐frequency sound‐absorbing materials and is of great significance for optimizing the acoustic performance of nanofiber membranes and expanding their applications in various acoustic engineering applications.
{"title":"Sound absorption properties and mechanism of multi‐layer micro‐perforated nanofiber membrane","authors":"Xiaofei Shao, Xiong Yan","doi":"10.1002/pat.6583","DOIUrl":"https://doi.org/10.1002/pat.6583","url":null,"abstract":"Aiming at achieving low‐frequency and broadband sound absorption under the premise of light and thin layers, in this paper, polyvinyl butyral (PVB) nanofiber membranes were micro‐perforated and then combined sequentially to prepare multi‐layer micro‐perforated nanofiber membrane (MPNM) for acoustic noise reduction. It was demonstrated that the multi‐layer MPNM exhibited a high absorption (constantly over 50%) in the frequency of 480–2500 Hz. In addition, the established theoretical model of the sound absorbing coefficient can accurately predict the sound absorption performance of the structure with different layers, which can provide a theoretical foundation for the design of the structure of the nanofibrous membrane acoustic absorber. Based on the proposed acoustic model, the relationships between the absorption properties and the parameters were investigated, and it was found that the effective acoustic absorption frequency range and acoustic absorption coefficient curve of the multi‐layer MPNM were closely related to the size and arrangement of hole diameter, perforation rate, fiber membrane thickness, and cavity depth. Optimization of the structural parameters utilizing algorithms can achieve superior sound absorption performance, with an average absorption coefficient of 0.81 in the frequency of 100–2500 Hz. This study provides a theoretical and experimental basis for the development of low‐frequency sound‐absorbing materials and is of great significance for optimizing the acoustic performance of nanofiber membranes and expanding their applications in various acoustic engineering applications.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"29 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142256996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The construction of flexible circuits is a crucial and challenging aspect in the design and fabrication of fabric‐based flexible electronics, which hold significant potential for various applications. In this study, we successfully developed high‐precision and durable fabric‐based flexible circuits by ingeniously combining ultraviolet light (UV)‐curing technology with chemical plating. Specifically, a UV coating containing Ag/Fe3O4 catalysts was applied onto polyester fabric surface, followed by printing the designed circuit structure diagram onto the fabric using UV light‐directed curing of the coating, and fabric‐based flexible circuits were then fabricated through chemical plating process. The fabric‐based flexible circuits exhibit only minimal increases in resistance following durability testing, including bending (8000 times), abrasion (2000 times), high and low temperature stability (−30 to 60°C), and high temperature/humidity stability (65°C, RH = 95%, 48 h), which remains consistently stable. This developed technology holds immense potential across various applications for smart wearable devices.
{"title":"Ultraviolet curing technology plus chemical copper plating: A novel method for producing highly durable fabric‐based flexible circuit","authors":"Maojiang Zhang, Kexin Cui, Xinwei Zhang, Jinghua Wang, Minglei Wang, Yanfu Wu, Chunlei Dong, Jie Gan, Jiangtao Hu, Guozhong Wu","doi":"10.1002/pat.6563","DOIUrl":"https://doi.org/10.1002/pat.6563","url":null,"abstract":"The construction of flexible circuits is a crucial and challenging aspect in the design and fabrication of fabric‐based flexible electronics, which hold significant potential for various applications. In this study, we successfully developed high‐precision and durable fabric‐based flexible circuits by ingeniously combining ultraviolet light (UV)‐curing technology with chemical plating. Specifically, a UV coating containing Ag/Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub> catalysts was applied onto polyester fabric surface, followed by printing the designed circuit structure diagram onto the fabric using UV light‐directed curing of the coating, and fabric‐based flexible circuits were then fabricated through chemical plating process. The fabric‐based flexible circuits exhibit only minimal increases in resistance following durability testing, including bending (8000 times), abrasion (2000 times), high and low temperature stability (−30 to 60°C), and high temperature/humidity stability (65°C, RH = 95%, 48 h), which remains consistently stable. This developed technology holds immense potential across various applications for smart wearable devices.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"61 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three‐dimensional (3D) printing, or additive manufacturing (AM), is rapidly advancing, allowing for the creation of objects from a digital model through the successive addition of materials. Among the AM techniques, fused deposition modeling (FDM) emerges as one of the most promising and extensively utilized methods. However, the inherent mechanical shortcomings of the deposition of pure thermoplastic materials necessitate the improvement of mechanical properties. One viable approach involves integrating reinforcing fibers into the thermoplastic matrix to create polymer composites suitable for structural applications. In this study, the mechanical properties of acrylonitrile butadiene styrene (ABS) reinforced with short glass fibers (SGFs) printed by FDM were investigated. The aim was to explore the impact of process parameters, including nozzle temperature, number of shells, and print speed, on the tensile properties and interlaminar shear strength (ILSS). Composite filament with 10% weight fraction (10 wt%) of glass fiber fabricated. Also, the mechanical properties of the composite and pure polymer were investigated. The length of the fibers was measured after the extrusion and printing process, revealing that they had been damaged. The shells exerted the most significant influence on test outcomes.
{"title":"Effect of printing parameters on the mechanical properties of 3D printed short glass fiber/acrylonitrile butadiene styrene composites","authors":"Moein Rahmati, Abbas Zolfaghari","doi":"10.1002/pat.6576","DOIUrl":"https://doi.org/10.1002/pat.6576","url":null,"abstract":"Three‐dimensional (3D) printing, or additive manufacturing (AM), is rapidly advancing, allowing for the creation of objects from a digital model through the successive addition of materials. Among the AM techniques, fused deposition modeling (FDM) emerges as one of the most promising and extensively utilized methods. However, the inherent mechanical shortcomings of the deposition of pure thermoplastic materials necessitate the improvement of mechanical properties. One viable approach involves integrating reinforcing fibers into the thermoplastic matrix to create polymer composites suitable for structural applications. In this study, the mechanical properties of acrylonitrile butadiene styrene (ABS) reinforced with short glass fibers (SGFs) printed by FDM were investigated. The aim was to explore the impact of process parameters, including nozzle temperature, number of shells, and print speed, on the tensile properties and interlaminar shear strength (ILSS). Composite filament with 10% weight fraction (10 wt%) of glass fiber fabricated. Also, the mechanical properties of the composite and pure polymer were investigated. The length of the fibers was measured after the extrusion and printing process, revealing that they had been damaged. The shells exerted the most significant influence on test outcomes.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"252 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel thermoplastic elastomer, kernel resin (KN), α‐nucleating agent (HPN), and β‐nucleating agent (DCHT), which acted as toughener and nucleating agents (NAs), were used to improve the mechanical properties and crystallization behaviors of isotactic polypropylene (PP). The impact strength of the PP/KN blends increased significantly with increase in KN concentration. Surprisingly, the impact strength of PP/KN/NA blends improved further upon addition of NA. The toughening effect of DCHT was stronger than that of HPN. The maximum impact strength of PP/KN/DCHT blend reached 69.2 kJ/m2 when the DCHT content was 0.05%, which was six times higher than that of neat PP. The SEM images of fractured surfaces of the blends showed a change from brittle fracture to ductile fracture. Moreover, the WAXD results showed that the incorporation of HPN promoted the formation of the α form of crystalline PP. Addition of DCHT induced the generation of α‐β crystal transition of PP. Furthermore, differential scanning calorimetry showed that the crystallizability and the overall crystallization rate of PP were enhanced by the addition of KN and NA. The half‐crystallization time of PP at 128°C decreased from 5.52 (neat PP) to 0.34 min (PP/KN/DCHT‐0.3).
{"title":"Synergistic toughening effects of elastomer toughener and nucleating agent on mechanical properties and crystallization behaviors of polypropylene","authors":"Ziwen Yin, Deyu Wei, Qing Lin, Hanlin Tian, Jinshuo Yu, Yanbo Li, Huiwen Deng, Zepeng Wang, Hongwei Pan, Yan Zhao, Huiliang Zhang","doi":"10.1002/pat.6578","DOIUrl":"https://doi.org/10.1002/pat.6578","url":null,"abstract":"A novel thermoplastic elastomer, kernel resin (KN), α‐nucleating agent (HPN), and β‐nucleating agent (DCHT), which acted as toughener and nucleating agents (NAs), were used to improve the mechanical properties and crystallization behaviors of isotactic polypropylene (PP). The impact strength of the PP/KN blends increased significantly with increase in KN concentration. Surprisingly, the impact strength of PP/KN/NA blends improved further upon addition of NA. The toughening effect of DCHT was stronger than that of HPN. The maximum impact strength of PP/KN/DCHT blend reached 69.2 kJ/m<jats:sup>2</jats:sup> when the DCHT content was 0.05%, which was six times higher than that of neat PP. The SEM images of fractured surfaces of the blends showed a change from brittle fracture to ductile fracture. Moreover, the WAXD results showed that the incorporation of HPN promoted the formation of the α form of crystalline PP. Addition of DCHT induced the generation of α‐β crystal transition of PP. Furthermore, differential scanning calorimetry showed that the crystallizability and the overall crystallization rate of PP were enhanced by the addition of KN and NA. The half‐crystallization time of PP at 128°C decreased from 5.52 (neat PP) to 0.34 min (PP/KN/DCHT‐0.3).","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"12 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiaoling Huang, Yuanyuan Feng, Xinming Dai, Shuang Guo, Shuning Ma, Amir A. Abdelsalam, Sensen Han
Wearable sensors based on nanomaterials have recently elicited keen research interest and potential for a new range of flexible devices. This paper presents a simple method for the preparation of laser‐induced porous graphene (LIG) and discusses its application in monitoring human vital signs. LIG formed on a polyimide (PI)/polydimethylsiloxane (PDMS) composite material exhibits inherent high stretchability (over 30%), eliminating the need for transfer processes used in LIG prepared by laser scribing on PI films. LIG/CuSO4 composite materials, with different concentrations of Cu particles, show tunable mechanical and electronic properties based on laser‐induced graphene. The fabricated LIG demonstrates good cyclic stability and a nearly linear resistance response to tensile strain, making it suitable for wearable electronic devices, the maximum strain value and linear response to applied strain from 3% to 79%. The sensor exhibits a fast response time and high sensitivity, enabling real‐time detection of human pulse, joint motion, and complex dynamics. The multifunctionality advantages of LIG flexible sensor offer potential applications in next‐generation wearable electronics.
基于纳米材料的可穿戴传感器近来引起了研究人员的浓厚兴趣，并有望成为一系列新的柔性设备。本文介绍了一种制备激光诱导多孔石墨烯（LIG）的简单方法，并讨论了其在监测人体生命体征方面的应用。在聚酰亚胺（PI）/聚二甲基硅氧烷（PDMS）复合材料上形成的石墨烯具有固有的高伸展性（超过 30%），无需在 PI 薄膜上通过激光划线制备石墨烯时使用的转移工艺。在激光诱导石墨烯的基础上，含有不同浓度铜颗粒的 LIG/CuSO4 复合材料显示出可调的机械和电子特性。所制造的 LIG 具有良好的循环稳定性，对拉伸应变的电阻响应接近线性，因此适用于可穿戴电子设备，其最大应变值和对施加应变的线性响应范围为 3% 至 79%。该传感器响应速度快、灵敏度高，可对人体脉搏、关节运动和复杂动态进行实时检测。LIG 柔性传感器的多功能优势为下一代可穿戴电子设备提供了潜在应用。
{"title":"Multifunctional strain sensor with adjustable conductive network for wearable applications","authors":"Qiaoling Huang, Yuanyuan Feng, Xinming Dai, Shuang Guo, Shuning Ma, Amir A. Abdelsalam, Sensen Han","doi":"10.1002/pat.6577","DOIUrl":"https://doi.org/10.1002/pat.6577","url":null,"abstract":"Wearable sensors based on nanomaterials have recently elicited keen research interest and potential for a new range of flexible devices. This paper presents a simple method for the preparation of laser‐induced porous graphene (LIG) and discusses its application in monitoring human vital signs. LIG formed on a polyimide (PI)/polydimethylsiloxane (PDMS) composite material exhibits inherent high stretchability (over 30%), eliminating the need for transfer processes used in LIG prepared by laser scribing on PI films. LIG/CuSO<jats:sub>4</jats:sub> composite materials, with different concentrations of Cu particles, show tunable mechanical and electronic properties based on laser‐induced graphene. The fabricated LIG demonstrates good cyclic stability and a nearly linear resistance response to tensile strain, making it suitable for wearable electronic devices, the maximum strain value and linear response to applied strain from 3% to 79%. The sensor exhibits a fast response time and high sensitivity, enabling real‐time detection of human pulse, joint motion, and complex dynamics. The multifunctionality advantages of LIG flexible sensor offer potential applications in next‐generation wearable electronics.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"37 5 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, polymers have been popular in industrial applications due to their lightweight, corrosion‐resistant, improved surface polish, ease of manufacturing, cost‐effectiveness, and so forth. Similarly, micro/nano‐indentation has gained popularity as a technique for assessing the surface mechanical characteristics of polymers. The present study conducted comprehensive experiments using cyclic micro‐indentation on engineering polymers, specifically poly‐ether‐ether‐ketone (PEEK), poly(methyl methacrylate) (PMMA), and poly(tetra‐fluoroethylene) (PTFE). An appropriate and optimal indentation method has been proposed after analyzing the behavior and significance of all the input parameters in evaluating the properties. Both constant load multi‐cycle (CLMC) and progressive load multi‐cycle (PLMC) were considered for this investigation. A comparative evaluation has been conducted to assess two multi‐cycle tests on these materials. From the analysis of the input parameters, including maximum loads, loading and unloading rates, and the number of cycles, the unloading rate and indentation cycle are crucial factors in determining hardness (H) and elastic modulus (E). Increasing the loading rates leads to an increase in H and a reduction in E for all three materials. This effect arises from the thermal effect, which is characterized by the creep modulus and a closed hysteresis loop. Employing the holding duration and multiple cycle data in constant load multi‐cycle can significantly influence the creep behavior and use of the hysteresis loop for fatigue behavior. Similarly, a progressive load multi‐cycle indentation with a force greater than 0.5 N and a minimum of five cycles is the most accurate approach for evaluating surface mechanical parameters.
近年来，聚合物因其重量轻、耐腐蚀、表面光洁度高、易于制造、成本效益高等优点而在工业应用中大受欢迎。同样，微/纳米压痕技术作为一种评估聚合物表面机械特性的技术也越来越受欢迎。本研究对工程聚合物，特别是聚醚醚酮（PEEK）、聚甲基丙烯酸甲酯（PMMA）和聚四氟乙烯（PTFE）进行了循环微压痕综合实验。在分析了所有输入参数在性能评估中的行为和意义后，提出了一种适当的最佳压痕方法。本次研究同时考虑了恒定载荷多循环（CLMC）和渐进载荷多循环（PLMC）两种方法。对这些材料的两种多循环测试进行了比较评估。从对输入参数（包括最大载荷、加载和卸载速率以及循环次数）的分析来看，卸载速率和压痕循环是决定硬度（H）和弹性模量（E）的关键因素。对于所有三种材料来说，加载速率的增加都会导致 H 的增加和 E 的减少。这种效应源于热效应，其特点是蠕变模量和闭合滞后环。在恒定载荷多循环中使用保持时间和多循环数据可以显著影响蠕变行为和疲劳行为滞后环的使用。同样，力大于 0.5 N 且至少循环五次的渐进加载多循环压痕是评估表面机械参数的最准确方法。
{"title":"Advancement of constant and progressive load multi‐cycle indentation method on surface properties characterization of polymers","authors":"Soumya Ranjan Guru, Mihir Sarangi","doi":"10.1002/pat.6573","DOIUrl":"https://doi.org/10.1002/pat.6573","url":null,"abstract":"In recent years, polymers have been popular in industrial applications due to their lightweight, corrosion‐resistant, improved surface polish, ease of manufacturing, cost‐effectiveness, and so forth. Similarly, micro/nano‐indentation has gained popularity as a technique for assessing the surface mechanical characteristics of polymers. The present study conducted comprehensive experiments using cyclic micro‐indentation on engineering polymers, specifically poly‐ether‐ether‐ketone (PEEK), poly(methyl methacrylate) (PMMA), and poly(tetra‐fluoroethylene) (PTFE). An appropriate and optimal indentation method has been proposed after analyzing the behavior and significance of all the input parameters in evaluating the properties. Both constant load multi‐cycle (CLMC) and progressive load multi‐cycle (PLMC) were considered for this investigation. A comparative evaluation has been conducted to assess two multi‐cycle tests on these materials. From the analysis of the input parameters, including maximum loads, loading and unloading rates, and the number of cycles, the unloading rate and indentation cycle are crucial factors in determining hardness (<jats:italic>H</jats:italic>) and elastic modulus (<jats:italic>E</jats:italic>). Increasing the loading rates leads to an increase in <jats:italic>H</jats:italic> and a reduction in <jats:italic>E</jats:italic> for all three materials. This effect arises from the thermal effect, which is characterized by the creep modulus and a closed hysteresis loop. Employing the holding duration and multiple cycle data in constant load multi‐cycle can significantly influence the creep behavior and use of the hysteresis loop for fatigue behavior. Similarly, a progressive load multi‐cycle indentation with a force greater than 0.5 N and a minimum of five cycles is the most accurate approach for evaluating surface mechanical parameters.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"14 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
γ‐Polyglutamic acid (γ‐PGA) microgel, produced by Bacillus spp., represents a promising biomaterial with diverse industrial applications due to its biodegradability, biocompatibility, and nontoxic nature. This review explores the current methodologies in the industrial production of γ‐PGA microgel, emphasizing the optimization of fermentation conditions, genetic engineering of Bacillus strains, and advances in downstream processing techniques. Key applications in pharmaceuticals, agriculture, and environmental management are discussed, highlighting its role in drug delivery systems, as a biocontrol agent, and in wastewater treatment. Future perspectives include enhancing production efficiency through synthetic biology, expanding its application scope, and addressing economic and regulatory challenges to facilitate broader adoption. The integration of innovative technologies and multidisciplinary approaches is crucial for the sustainable development and commercial success of γ‐PGA microgel.
{"title":"Production of gamma‐polyglutamic acid microgel by Bacillus species: Industrial applications and future perspectives","authors":"Priti Pal, Akhilesh Kumar Singh, Prakash Kumar Sarangi, Uttam Kumar Sahoo, Harikesh B. Singh, Sanjukta Subudhi, Thangjam Anand Singh","doi":"10.1002/pat.6565","DOIUrl":"https://doi.org/10.1002/pat.6565","url":null,"abstract":"γ‐Polyglutamic acid (γ‐PGA) microgel, produced by <jats:italic>Bacillus</jats:italic> spp., represents a promising biomaterial with diverse industrial applications due to its biodegradability, biocompatibility, and nontoxic nature. This review explores the current methodologies in the industrial production of γ‐PGA microgel, emphasizing the optimization of fermentation conditions, genetic engineering of <jats:italic>Bacillus</jats:italic> strains, and advances in downstream processing techniques. Key applications in pharmaceuticals, agriculture, and environmental management are discussed, highlighting its role in drug delivery systems, as a biocontrol agent, and in wastewater treatment. Future perspectives include enhancing production efficiency through synthetic biology, expanding its application scope, and addressing economic and regulatory challenges to facilitate broader adoption. The integration of innovative technologies and multidisciplinary approaches is crucial for the sustainable development and commercial success of γ‐PGA microgel.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relentless drive towards miniaturization and seamless integration of electronic components in wireless communications and wearable devices has significantly increased the demand for flexible, cost‐effective composites with high dielectric constants and low losses. This study presents a wideband, low‐profile, and flexible antenna with excellent on body radiation performance for wearable applications. The antenna is designed using a low‐loss composite film based on PMMA‐PVDF‐HFP‐PZT and silver‐based ink. The proposed flexible antenna exhibits a wide bandwidth of 132.16% with a voltage standing wave ratio (VSWR) of less than two. It achieves a peak gain of 2.76 dBi at 2.92 GHz and maintains a maximum radiation efficiency of 80% across the 1.26–6.17 GHz frequency range. These characteristics demonstrate that the antenna is an effective solution for achieving high data rates and reliable communication links. The antenna's suitability for wearable applications is assessed by testing it on a simulated human body and analyzing its behavior under physical deformation. The results under bending showed only a minimal frequency detuning, which is negligible given the antenna's wide operational bandwidth. The specific absorption rate (SAR) analysis shows values of approximately 1.88 W/kg at 3.5 GHz with an input power of 0.5 W, and 0.279 W/kg at 5.8 GHz with an input power of 0.45 W, which complies with established safety limits for exposure. Overall, these results suggest that the proposed antenna is a viable solution for integration into wearable medical devices, such as a doctor's chest badge, enabling noncontact interactions and reducing the risk of bacterial contamination.
{"title":"A wideband flexible antenna utilizing PMMA/PVDF‐HFP/PZT polymer composite film and silver‐based conductive ink for wearable applications","authors":"Saïd Douhi, Abdelkrim Boumegnane, Nabil Chakhchaoui, Adil Eddiai, Omar Cherkaoui, M'hammed Mazroui","doi":"10.1002/pat.6575","DOIUrl":"https://doi.org/10.1002/pat.6575","url":null,"abstract":"The relentless drive towards miniaturization and seamless integration of electronic components in wireless communications and wearable devices has significantly increased the demand for flexible, cost‐effective composites with high dielectric constants and low losses. This study presents a wideband, low‐profile, and flexible antenna with excellent on body radiation performance for wearable applications. The antenna is designed using a low‐loss composite film based on PMMA‐PVDF‐HFP‐PZT and silver‐based ink. The proposed flexible antenna exhibits a wide bandwidth of 132.16% with a voltage standing wave ratio (VSWR) of less than two. It achieves a peak gain of 2.76 dBi at 2.92 GHz and maintains a maximum radiation efficiency of 80% across the 1.26–6.17 GHz frequency range. These characteristics demonstrate that the antenna is an effective solution for achieving high data rates and reliable communication links. The antenna's suitability for wearable applications is assessed by testing it on a simulated human body and analyzing its behavior under physical deformation. The results under bending showed only a minimal frequency detuning, which is negligible given the antenna's wide operational bandwidth. The specific absorption rate (SAR) analysis shows values of approximately 1.88 W/kg at 3.5 GHz with an input power of 0.5 W, and 0.279 W/kg at 5.8 GHz with an input power of 0.45 W, which complies with established safety limits for exposure. Overall, these results suggest that the proposed antenna is a viable solution for integration into wearable medical devices, such as a doctor's chest badge, enabling noncontact interactions and reducing the risk of bacterial contamination.","PeriodicalId":20382,"journal":{"name":"Polymers for Advanced Technologies","volume":"15 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142208240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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