Hitesh Sharma, Sandeep Gairola, Joy Prakash Misra, Inderdeep Singh
This study presents an innovative technique for recycling leftover epoxy composites reinforced with natural fillers. The waste epoxy composites were successfully ground into a 75–150 μm fine powder. With the aid of extrusion injection molding, this powder was subsequently utilized to create polypropylene matrix‐based polymer composites with variable filler loadings ranging from 10% to 30%. The mechanical, thermal, thermomechanical, and morphological properties of the developed composites were assessed. The greatest tensile strength of the polypropylene composites produced with 10% filler loading was found to be 24.15 MPa. The addition of epoxy composite filler increased the thermal stability. During morphological investigations, it was discovered that pits, voids, and filler agglomerations predominated the fractured surface of the developed composites. Overall, it can be concluded that there is a lot of promise for value‐added recycling of thermosetting resin‐based composites using this low‐cost, high‐efficiency, and ecologically benign process, which would lessen the environmental impact of plastic.HighlightsNovel polypropylene composites using epoxy composite dust was developed.Mechanical, thermal, thermomechanical, and morphological studies were performed.Toys, tableware, mementos, and furniture can be the potential applications.The developed composites can reduce plastic load on the environment.
{"title":"Epoxy composite dust reinforced novel polypropylene composites: An eco‐friendly approach toward sustainable resource management","authors":"Hitesh Sharma, Sandeep Gairola, Joy Prakash Misra, Inderdeep Singh","doi":"10.1002/pen.26968","DOIUrl":"https://doi.org/10.1002/pen.26968","url":null,"abstract":"<jats:label/>This study presents an innovative technique for recycling leftover epoxy composites reinforced with natural fillers. The waste epoxy composites were successfully ground into a 75–150 μm fine powder. With the aid of extrusion injection molding, this powder was subsequently utilized to create polypropylene matrix‐based polymer composites with variable filler loadings ranging from 10% to 30%. The mechanical, thermal, thermomechanical, and morphological properties of the developed composites were assessed. The greatest tensile strength of the polypropylene composites produced with 10% filler loading was found to be 24.15 MPa. The addition of epoxy composite filler increased the thermal stability. During morphological investigations, it was discovered that pits, voids, and filler agglomerations predominated the fractured surface of the developed composites. Overall, it can be concluded that there is a lot of promise for value‐added recycling of thermosetting resin‐based composites using this low‐cost, high‐efficiency, and ecologically benign process, which would lessen the environmental impact of plastic.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Novel polypropylene composites using epoxy composite dust was developed.</jats:list-item> <jats:list-item>Mechanical, thermal, thermomechanical, and morphological studies were performed.</jats:list-item> <jats:list-item>Toys, tableware, mementos, and furniture can be the potential applications.</jats:list-item> <jats:list-item>The developed composites can reduce plastic load on the environment.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252571","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}
Nanosilica reinforced epoxy‐matrix composites have been extensively investigated for higher mechanical strengths since its emergence, while few literatures are available about enhancement characteristics under super high strain rate loading, which is usually encountered during impact. Hereby, this work investigates the composites containing various kinds of nanosilica subjected to compression of strain rate higher than 20,000 s−1. A series of stress:strain curves are obtained and it is found that peak stresses increase with increasing strain rate along with silica fraction. Excitedly, the silica particle plays another enhancement role in anti‐localization of adiabatic shearing which occurs in pure epoxy, as indicated from abruptly dropped strain‐hardening index at ~22,000 s−1. A mechanism is proposed that uniformly distributed silica delays adiabatic shearing localizations to form through cracks, which is confirmed by fracture surface observance.HighlightsHigher strain rate is achieved experimentally up to ~20,000 s−1.Strain rate effect is found on the peak stress of composites.Reinforcement of nanosilica is more distinct on strain‐hardening behavior.Silica particles hinder adjacent shearing localizations from abrupt evolution.
{"title":"Nanosilica reinforced epoxy under super high strain rate loading","authors":"Zhibo Wu, Chenxu Zhang, Jianping Yin, Zhongbin Tang, Yinggang Miao","doi":"10.1002/pen.26966","DOIUrl":"https://doi.org/10.1002/pen.26966","url":null,"abstract":"<jats:label/>Nanosilica reinforced epoxy‐matrix composites have been extensively investigated for higher mechanical strengths since its emergence, while few literatures are available about enhancement characteristics under super high strain rate loading, which is usually encountered during impact. Hereby, this work investigates the composites containing various kinds of nanosilica subjected to compression of strain rate higher than 20,000 s<jats:sup>−1</jats:sup>. A series of stress:strain curves are obtained and it is found that peak stresses increase with increasing strain rate along with silica fraction. Excitedly, the silica particle plays another enhancement role in anti‐localization of adiabatic shearing which occurs in pure epoxy, as indicated from abruptly dropped strain‐hardening index at ~22,000 s<jats:sup>−1</jats:sup>. A mechanism is proposed that uniformly distributed silica delays adiabatic shearing localizations to form through cracks, which is confirmed by fracture surface observance.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Higher strain rate is achieved experimentally up to ~20,000 s<jats:sup>−1</jats:sup>.</jats:list-item> <jats:list-item>Strain rate effect is found on the peak stress of composites.</jats:list-item> <jats:list-item>Reinforcement of nanosilica is more distinct on strain‐hardening behavior.</jats:list-item> <jats:list-item>Silica particles hinder adjacent shearing localizations from abrupt evolution.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252572","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 mechanical properties of roadbed rehabilitation polyurethane grouting material (RhPU) under freeze–thaw cycles are the theoretical basis for evaluating its long‐term performance in cold regions, but are currently not well understood. Freeze–thaw cycle tests were conducted on RhPU grouting materials of different densities using a rapid freezing method to investigate the effects of damage characteristics of RhPU. The experimental results indicate that the frost damage of RhPU is a fatigue failure process from the outside to the inside. During the freeze–thaw cycle, water‐filled cells experience compression damage due to freezing expansion and interconnected, forming more water seepage channels, accelerating the internal damage of RhPU. Therefore, the dynamic elastic modulus, longitudinal wave velocity, rigidity, and compressive strength of RhPU all decrease with an increase in freeze–thaw cycles. Moreover, at the same freeze–thaw cycles, the lower the density of RhPU, the greater the loss rate of the dynamic elastic modulus, longitudinal wave velocity, rigidity, and compressive strength. The square of the longitudinal wave velocity of RhPU samples before and after freeze–thaw cycles correlates well with density, and the longitudinal wave velocity loss rate better quantifies the internal damage of RhPU samples. Through scanning electron microscopy, the microstructure of RhPU after freeze–thaw cycles was observed, revealing that the lower density of RhPU exhibits more severe freeze–thaw damage compared to higher density RhPU, attributed to its larger cell diameter and greater contact area between adjacent cells. This indicates poorer freeze resistance performance for low‐density RhPU.HighlightsThe variations of surface damage of RhPU after freeze–thaw cycles were studied.The correlation between and density of RhPU after freeze–thaw cycles was found.The effect of freeze–thaw cycles on mechanical properties of RhPU was analyzed.The microscale freeze–thaw damage mechanism of RhPU was revealed.
{"title":"Study on mechanical properties of a roadbed rehabilitation polyurethane grouting material after freeze–thaw cycles","authors":"Zixuan Wang, Mingrui Du, Hongyuan Fang, Chao Zhang, Peng Zhao, Xupei Yao, Feng Xiao","doi":"10.1002/pen.26946","DOIUrl":"https://doi.org/10.1002/pen.26946","url":null,"abstract":"<jats:label/>The mechanical properties of roadbed rehabilitation polyurethane grouting material (RhPU) under freeze–thaw cycles are the theoretical basis for evaluating its long‐term performance in cold regions, but are currently not well understood. Freeze–thaw cycle tests were conducted on RhPU grouting materials of different densities using a rapid freezing method to investigate the effects of damage characteristics of RhPU. The experimental results indicate that the frost damage of RhPU is a fatigue failure process from the outside to the inside. During the freeze–thaw cycle, water‐filled cells experience compression damage due to freezing expansion and interconnected, forming more water seepage channels, accelerating the internal damage of RhPU. Therefore, the dynamic elastic modulus, longitudinal wave velocity, rigidity, and compressive strength of RhPU all decrease with an increase in freeze–thaw cycles. Moreover, at the same freeze–thaw cycles, the lower the density of RhPU, the greater the loss rate of the dynamic elastic modulus, longitudinal wave velocity, rigidity, and compressive strength. The square of the longitudinal wave velocity of RhPU samples before and after freeze–thaw cycles correlates well with density, and the longitudinal wave velocity loss rate better quantifies the internal damage of RhPU samples. Through scanning electron microscopy, the microstructure of RhPU after freeze–thaw cycles was observed, revealing that the lower density of RhPU exhibits more severe freeze–thaw damage compared to higher density RhPU, attributed to its larger cell diameter and greater contact area between adjacent cells. This indicates poorer freeze resistance performance for low‐density RhPU.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The variations of surface damage of RhPU after freeze–thaw cycles were studied.</jats:list-item> <jats:list-item>The correlation between and density of RhPU after freeze–thaw cycles was found.</jats:list-item> <jats:list-item>The effect of freeze–thaw cycles on mechanical properties of RhPU was analyzed.</jats:list-item> <jats:list-item>The microscale freeze–thaw damage mechanism of RhPU was revealed.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252574","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}
Filipe R. Pê, Túlio A. C. S. Rodrigues, Rafael B. da Cunha, Shirley N. Cavalcanti, Moacy P. da Silva, Pankaj Agrawal, Gustavo F. Brito, Tomás J. A. de Mélo
In this study, the effect of the polymer matrix structure on the rheological and electrical percolation threshold of polymer/carbon black (CB) conductive polymer composites (CPCs) was investigated. Poly(lactic acid) (PLA) and high‐density polyethylene (HDPE) were used as polymer matrices. Through rheological analyses, an increase in complex viscosity was observed with increasing CB concentration, accompanied by a reduction in the Newtonian plateau. Additionally, an increase in the solid‐like behavior was observed, suggesting the formation of a percolated network. The rheological percolation threshold was found to be 5.13% CB mass fraction for the PLA/CB composite and 10.72% for the HDPE/CB composite. Electrical conductivity results were fitted to the sigmoidal Boltzmann model, and its derivative was used to identify the electrical percolation threshold. For PLA/CB, this threshold was reached at 5.39% CB mass fraction, while for HDPE/CB, it occurred at 5.75%. Morphology analysis by scanning electron microscopy and atomic force microscopy indicated that the polymer matrix structure affected the distribution/dispersion of the CB particles within the polymer matrix.HighlightsThe effect of polymer matrix structure on polymer/CB CPCs was investigated.The crystallinity of the polymer matrix affected the percolation threshold.PLA/CB showed higher conductivity than HDPE/CB CPCs.
{"title":"PLA/CB and HDPE/CB conductive polymer composites: Effect of polymer matrix structure on the rheological and electrical percolation threshold","authors":"Filipe R. Pê, Túlio A. C. S. Rodrigues, Rafael B. da Cunha, Shirley N. Cavalcanti, Moacy P. da Silva, Pankaj Agrawal, Gustavo F. Brito, Tomás J. A. de Mélo","doi":"10.1002/pen.26965","DOIUrl":"https://doi.org/10.1002/pen.26965","url":null,"abstract":"<jats:label/>In this study, the effect of the polymer matrix structure on the rheological and electrical percolation threshold of polymer/carbon black (CB) conductive polymer composites (CPCs) was investigated. Poly(lactic acid) (PLA) and high‐density polyethylene (HDPE) were used as polymer matrices. Through rheological analyses, an increase in complex viscosity was observed with increasing CB concentration, accompanied by a reduction in the Newtonian plateau. Additionally, an increase in the solid‐like behavior was observed, suggesting the formation of a percolated network. The rheological percolation threshold was found to be 5.13% CB mass fraction for the PLA/CB composite and 10.72% for the HDPE/CB composite. Electrical conductivity results were fitted to the sigmoidal Boltzmann model, and its derivative was used to identify the electrical percolation threshold. For PLA/CB, this threshold was reached at 5.39% CB mass fraction, while for HDPE/CB, it occurred at 5.75%. Morphology analysis by scanning electron microscopy and atomic force microscopy indicated that the polymer matrix structure affected the distribution/dispersion of the CB particles within the polymer matrix.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The effect of polymer matrix structure on polymer/CB CPCs was investigated.</jats:list-item> <jats:list-item>The crystallinity of the polymer matrix affected the percolation threshold.</jats:list-item> <jats:list-item>PLA/CB showed higher conductivity than HDPE/CB CPCs.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252576","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 rapid development of lithium battery technology is leading to the increasing miniaturization of electronic devices, thereby elevating the demand for dielectric materials with exceptionally high thermal conductivity and dielectric properties. In this study, the composites were fabricated by integrating multilayer core‐shell hybrid structure particles into silicone rubber (SR). These particles were created by attaching the conductive polymer polypyrrole (PPy) and the silane coupling agent (KH570) onto the surface of highly thermally conductive ceramic particles aluminum nitride (AlN). The combination of PPy and KH570 serves to enhance the interfacial compatibility between AlN and SR, thereby concurrently enhancing the thermal conductivity and dielectric properties of the composites. The experimental results demonstrated that the thermal conductivity of the 50 phr AlN‐PPy‐KH570/SR composite was 0.37 W/(m · K), 1.65 times higher than that of pure SR (0.23 W/(m · K)). Additionally, the dielectric constant of the composite increased to 4.59, 1.32 times that of pure SR (3.48). Moreover, the thermal decomposition temperature of the composite was elevated to 475°C. The synthesized SR composites hold promise for widespread use in miniaturized electronic devices operating in high‐frequency and high‐temperature environments.
{"title":"Synchronously enhanced thermal conductivity and dielectric properties of silicone rubber composites filled with the AlN‐PPy‐KH570 multilayer core‐shell hybrid structure","authors":"Ke Yang, Yanru Chen, Hanhai Dong, Jinqing Jiao, Xuqing Lang, Qingli Cheng","doi":"10.1002/pen.26956","DOIUrl":"https://doi.org/10.1002/pen.26956","url":null,"abstract":"The rapid development of lithium battery technology is leading to the increasing miniaturization of electronic devices, thereby elevating the demand for dielectric materials with exceptionally high thermal conductivity and dielectric properties. In this study, the composites were fabricated by integrating multilayer core‐shell hybrid structure particles into silicone rubber (SR). These particles were created by attaching the conductive polymer polypyrrole (PPy) and the silane coupling agent (KH570) onto the surface of highly thermally conductive ceramic particles aluminum nitride (AlN). The combination of PPy and KH570 serves to enhance the interfacial compatibility between AlN and SR, thereby concurrently enhancing the thermal conductivity and dielectric properties of the composites. The experimental results demonstrated that the thermal conductivity of the 50 phr AlN‐PPy‐KH570/SR composite was 0.37 W/(m · K), 1.65 times higher than that of pure SR (0.23 W/(m · K)). Additionally, the dielectric constant of the composite increased to 4.59, 1.32 times that of pure SR (3.48). Moreover, the thermal decomposition temperature of the composite was elevated to 475°C. The synthesized SR composites hold promise for widespread use in miniaturized electronic devices operating in high‐frequency and high‐temperature environments.","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252575","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}
Recycled post‐consumer rigid polyethylene (PE) packaging waste was washed and compounded on a pilot scale using different processing conditions and the processability of recycled materials with blow molding was assessed. Compared to virgin grade high‐density PE, the recycled materials showed a lower crystallinity, a lower thermo‐oxidative stability, a higher ash content, a lower viscosity and melt elasticity, and a lower melt strength and drawability. The thermo‐oxidative stability varied due to the different washing media. Rheological characterization by frequency‐sweep measurements indicated that the virgin grade PE had as expected more linear‐polymer‐like characteristics whereas the recycled materials showed chain branching or crosslinking related to the processing condition during compounding. The recycled materials were successfully blow molded into 4 L‐containers where they showed less resistance to flow than the virgin grade PE. The recycled materials differed in color when different washing media were used. There were no significant differences in the mechanical properties of the 4 L‐containers made of virgin grade and recycled PE.HighlightsWashing, compounding, and blow molding of rigid polyethylene packaging waste were studied.The degradation varied depending on the washing and compounding conditions.Rheological results indicated chain branching or crosslinking due to degradation.
回收的消费后硬质聚乙烯（PE）包装废弃物经过清洗后，在试验规模上采用不同的加工条件进行复合，并对回收材料的吹塑成型加工性能进行了评估。与原生级高密度聚乙烯相比，回收材料的结晶度较低、热氧化稳定性较低、灰分含量较高、粘度和熔体弹性较低、熔体强度和拉伸性较低。热氧化稳定性因清洗介质的不同而不同。通过频率扫描测量进行的流变特性分析表明，原聚乙烯具有更多类似线性聚合物的预期特性，而回收材料则显示出与复合过程中的加工条件有关的链分支或交联。回收材料被成功吹塑成 4 L 容器，其流动阻力小于原生级聚乙烯。在使用不同的清洗介质时，回收材料的颜色有所不同。对硬质聚乙烯包装废料的清洗、混合和吹塑成型进行了研究。降解情况随清洗和复合条件的不同而变化。流变学结果表明，降解导致了链的分支或交联。
{"title":"Blow molding of mechanically recycled post‐consumer rigid polyethylene packaging waste","authors":"Ezgi Ceren Boz Noyan, Antal Boldizar","doi":"10.1002/pen.26962","DOIUrl":"https://doi.org/10.1002/pen.26962","url":null,"abstract":"<jats:label/>Recycled post‐consumer rigid polyethylene (PE) packaging waste was washed and compounded on a pilot scale using different processing conditions and the processability of recycled materials with blow molding was assessed. Compared to virgin grade high‐density PE, the recycled materials showed a lower crystallinity, a lower thermo‐oxidative stability, a higher ash content, a lower viscosity and melt elasticity, and a lower melt strength and drawability. The thermo‐oxidative stability varied due to the different washing media. Rheological characterization by frequency‐sweep measurements indicated that the virgin grade PE had as expected more linear‐polymer‐like characteristics whereas the recycled materials showed chain branching or crosslinking related to the processing condition during compounding. The recycled materials were successfully blow molded into 4 L‐containers where they showed less resistance to flow than the virgin grade PE. The recycled materials differed in color when different washing media were used. There were no significant differences in the mechanical properties of the 4 L‐containers made of virgin grade and recycled PE.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Washing, compounding, and blow molding of rigid polyethylene packaging waste were studied.</jats:list-item> <jats:list-item>The degradation varied depending on the washing and compounding conditions.</jats:list-item> <jats:list-item>Rheological results indicated chain branching or crosslinking due to degradation.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252577","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 microarchitectured polyolefin surfaces are currently used intensively in various industrial applications. However, the deployment of products made of these materials into practical application is typically constrained by their inferior dry sliding behaviors, which stem from their limited strength and toughness. To obtain reinforced and toughened superhydrophobic microstructured surfaces that can be easy to demold and overcome friction in the workplace, elastomeric ethylene–octene copolymer (POE) and rigid graphene (GP) were introduced into the polypropylene (PP) matrix to prepare microstructured PP/POE/GP surfaces by compression molding. The elongation at break is significantly improved by 2000% and reached up to 520.33%. The contact angle (CA) of the microstructured PP/POE/GP surface increases to 154.4°. They exhibit superhydrophobic and low adhesion characteristic, that is, lotus effect. The enhanced toughness of PP/POE/GP composites reduces wear debris and damage to microarchitecture during the abrasion process. Even after the microstructured PP/POE/GP surfaces were worn after a distance length of 3000 mm, they still exhibited superhydrophobic, but high adhesion characteristic, that is, petal effect. The controlled shape‐morphing microarchitectures formed on the microstructured PP/POE/GP surface abraded after 1000 mm, possessing wetting stability during droplet impacting.HighlightsThe elongation at break of composites was improved by 2000% through adding POE.The composite microstructure deforms to consume energy during abrasion and POE reinforces this energy dissipation process.POE improves fracture toughness and wetting stability of composites.
{"title":"Compression molding of ethylene–octene copolymer‐toughened polypropylene/graphene surfaces with actively controlled shape‐morphing microarchitectures induced by friction and wear","authors":"Jiayi He, Weiting Wu, Jinhua Xu, Sha Ding, Xin Zhang, Jingjing Zhang, Caihong Lei, Anfu Chen, Lijia Huang","doi":"10.1002/pen.26951","DOIUrl":"https://doi.org/10.1002/pen.26951","url":null,"abstract":"<jats:label/>Superhydrophobic microarchitectured polyolefin surfaces are currently used intensively in various industrial applications. However, the deployment of products made of these materials into practical application is typically constrained by their inferior dry sliding behaviors, which stem from their limited strength and toughness. To obtain reinforced and toughened superhydrophobic microstructured surfaces that can be easy to demold and overcome friction in the workplace, elastomeric ethylene–octene copolymer (POE) and rigid graphene (GP) were introduced into the polypropylene (PP) matrix to prepare microstructured PP/POE/GP surfaces by compression molding. The elongation at break is significantly improved by 2000% and reached up to 520.33%. The contact angle (CA) of the microstructured PP/POE/GP surface increases to 154.4°. They exhibit superhydrophobic and low adhesion characteristic, that is, lotus effect. The enhanced toughness of PP/POE/GP composites reduces wear debris and damage to microarchitecture during the abrasion process. Even after the microstructured PP/POE/GP surfaces were worn after a distance length of 3000 mm, they still exhibited superhydrophobic, but high adhesion characteristic, that is, petal effect. The controlled shape‐morphing microarchitectures formed on the microstructured PP/POE/GP surface abraded after 1000 mm, possessing wetting stability during droplet impacting.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The elongation at break of composites was improved by 2000% through adding POE.</jats:list-item> <jats:list-item>The composite microstructure deforms to consume energy during abrasion and POE reinforces this energy dissipation process.</jats:list-item> <jats:list-item>POE improves fracture toughness and wetting stability of composites.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219292","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}
Although the influence of hard segment content on the foaming behavior of thermoplastic polyurethane (TPU) has been reported in the literature, most of the studies have been limited to batch foaming, and the relationship between hardness on the foaming quality and the surface quality of TPU is still unclear in injection molding foaming. In this study, three hardnesses of TPU foams were prepared by core‐back injection foaming technique to investigate the relationship between hardness and TPU foaming behavior. Firstly, the relationship between hardness and viscosity of TPU was investigated using rotational rheometer. The results showed that the complex viscosity increased with the increase of hardness, especially the viscosity of high hardness TPU responded more significantly at low frequencies. In addition, a scanning electron microscope was used to analyze the cell morphology of TPU foams with different hardness. It was revealed that the cell morphology of 1098A foam with low hardness was deteriorated and deformed severely, with a cell size and cell density of 172.02 μm and 0.59 × 105 cells/cm3, respectively. With the increase of hardness, the cell morphology of high hardness 1071D foam was regular and rounded, its cell size decreased to 95.98 μm and cell density increased 4.43 × 105 cells/cm3. Surface roughness and mechanical experiments showed that the medium hardness 1065D foam had better surface quality and tensile toughness. The elongation at break of the TPU foams decreased with increasing hardness, while the high hardness 1071D foam had better tensile and flexural strength. This study provides understanding for the selection of a suitable hardness to prepare TPU foams with favorable foaming quality and corresponding mechanical properties.HighlightsTPU foams of different hardness were prepared using core‐back chemical foaming injection molding technology.High hardness TPU foam had excellent tensile strength and flexural strength.
{"title":"Effect of hardness on the foaming behavior, surface quality, and mechanical properties of thermoplastic polyurethane foams by chemical foaming injection molding","authors":"Jinfu Xing, Li He, Tuanhui Jiang","doi":"10.1002/pen.26959","DOIUrl":"https://doi.org/10.1002/pen.26959","url":null,"abstract":"<jats:label/>Although the influence of hard segment content on the foaming behavior of thermoplastic polyurethane (TPU) has been reported in the literature, most of the studies have been limited to batch foaming, and the relationship between hardness on the foaming quality and the surface quality of TPU is still unclear in injection molding foaming. In this study, three hardnesses of TPU foams were prepared by core‐back injection foaming technique to investigate the relationship between hardness and TPU foaming behavior. Firstly, the relationship between hardness and viscosity of TPU was investigated using rotational rheometer. The results showed that the complex viscosity increased with the increase of hardness, especially the viscosity of high hardness TPU responded more significantly at low frequencies. In addition, a scanning electron microscope was used to analyze the cell morphology of TPU foams with different hardness. It was revealed that the cell morphology of 1098A foam with low hardness was deteriorated and deformed severely, with a cell size and cell density of 172.02 μm and 0.59 × 10<jats:sup>5</jats:sup> cells/cm<jats:sup>3</jats:sup>, respectively. With the increase of hardness, the cell morphology of high hardness 1071D foam was regular and rounded, its cell size decreased to 95.98 μm and cell density increased 4.43 × 10<jats:sup>5</jats:sup> cells/cm<jats:sup>3</jats:sup>. Surface roughness and mechanical experiments showed that the medium hardness 1065D foam had better surface quality and tensile toughness. The elongation at break of the TPU foams decreased with increasing hardness, while the high hardness 1071D foam had better tensile and flexural strength. This study provides understanding for the selection of a suitable hardness to prepare TPU foams with favorable foaming quality and corresponding mechanical properties.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>TPU foams of different hardness were prepared using core‐back chemical foaming injection molding technology.</jats:list-item> <jats:list-item>High hardness TPU foam had excellent tensile strength and flexural strength.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219299","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}
Additive manufacturing (AM) of polymers is a highly versatile technology that can be applied to many independent sectors like automotive, aviation, medicine, and dentistry. Since it has great potential for rapid prototyping, clean‐process concepts, and the ability to produce complex shapes, the layer‐by‐layer printing method is one of the most promising alternatives for future industrial production efforts. In that sense, different from the previous studies, this work aims to elucidate the friction and wear properties of the special dental samples manufactured via photopolymerization‐based AM technology according to both for printing parameters, and dry sliding test variables. Also, this is the first initiation to examine the combined influences of the UV exposure time, building direction, and sliding force on the surface roughness, hardness, friction coefficient, wear rate, and main plastic damage mechanism of the printed samples. The results showed that the maximum average hardness value was detected as 89.8 Shore D for vertically built samples printed with 8 s exposure time. In addition, vertically printed samples exhibited better wear resistance than the horizontal samples and the rising exposure time generally affected affirmatively the hardness levels of the samples. The lowest volume loss of 78 mm3 belonged to the vertical sample at 5 N. Further, increasing test force levels caused a decrease in the friction coefficient results and triggered the volume loss increase in the samples. Among all samples, the calculated friction coefficient values changed between 0.3 and 0.87. On the other side, scanning electron microscopy (SEM), and energy‐dispersive spectroscopy (EDS) analyses pointed out that ascending exposure times led to the altering contact surface matchings determining the final volume loss outcomes.HighlightsTo obtain better surface quality, vertical printing was a useful option.Horizontally printed samples exhibited higher friction coefficients.Curing time positively impacted the wear resistance for both orientations.Grooves and debris parts were observed on surfaces with low exposure times.
{"title":"An investigation on the wear properties of the photocurable components produced by additive manufacturing for dentistry applications: Combined influences of UV exposure time, building direction, and sliding loads","authors":"Çağın Bolat, Serkan Salmaz","doi":"10.1002/pen.26960","DOIUrl":"https://doi.org/10.1002/pen.26960","url":null,"abstract":"<jats:label/>Additive manufacturing (AM) of polymers is a highly versatile technology that can be applied to many independent sectors like automotive, aviation, medicine, and dentistry. Since it has great potential for rapid prototyping, clean‐process concepts, and the ability to produce complex shapes, the layer‐by‐layer printing method is one of the most promising alternatives for future industrial production efforts. In that sense, different from the previous studies, this work aims to elucidate the friction and wear properties of the special dental samples manufactured via photopolymerization‐based AM technology according to both for printing parameters, and dry sliding test variables. Also, this is the first initiation to examine the combined influences of the UV exposure time, building direction, and sliding force on the surface roughness, hardness, friction coefficient, wear rate, and main plastic damage mechanism of the printed samples. The results showed that the maximum average hardness value was detected as 89.8 Shore D for vertically built samples printed with 8 s exposure time. In addition, vertically printed samples exhibited better wear resistance than the horizontal samples and the rising exposure time generally affected affirmatively the hardness levels of the samples. The lowest volume loss of 78 mm<jats:sup>3</jats:sup> belonged to the vertical sample at 5 N. Further, increasing test force levels caused a decrease in the friction coefficient results and triggered the volume loss increase in the samples. Among all samples, the calculated friction coefficient values changed between 0.3 and 0.87. On the other side, scanning electron microscopy (SEM), and energy‐dispersive spectroscopy (EDS) analyses pointed out that ascending exposure times led to the altering contact surface matchings determining the final volume loss outcomes.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>To obtain better surface quality, vertical printing was a useful option.</jats:list-item> <jats:list-item>Horizontally printed samples exhibited higher friction coefficients.</jats:list-item> <jats:list-item>Curing time positively impacted the wear resistance for both orientations.</jats:list-item> <jats:list-item>Grooves and debris parts were observed on surfaces with low exposure times.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219296","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}
Hao Zhang, Xiaocheng Chu, Qingjun Ding, Gai Zhao, Huafeng Li
This study investigates the impact of zinc oxide nanoparticles on epoxy resin systems and the ultraviolet (UV) aging resistance of modified epoxy resin composites using molecular dynamics (MD) simulations and experimental methods. Initially, various epoxy resin cross‐linking models are established through MD simulations to understand the influence of different nano ZnO contents on resin modification, further validated by experiments. Subsequently, the UV radiation resistance of nano ZnO–epoxy resin composites is assessed by subjecting them to high‐intensity UV radiation equivalent to 3 years of natural environmental conditions, analyzing changes in tensile properties, impact performance, hardness, and glass transition temperature of epoxy resin before and after UV radiation exposure. The findings suggest that the addition of nano zinc oxide reduces the impact of UV radiation on epoxy resin, with optimal UV radiation resistance observed at a nano zinc oxide mass fraction of 0.3 wt%.
{"title":"Study on the UV aging resistance of ZnO‐modified epoxy resin by experiments and MD simulation","authors":"Hao Zhang, Xiaocheng Chu, Qingjun Ding, Gai Zhao, Huafeng Li","doi":"10.1002/pen.26957","DOIUrl":"https://doi.org/10.1002/pen.26957","url":null,"abstract":"This study investigates the impact of zinc oxide nanoparticles on epoxy resin systems and the ultraviolet (UV) aging resistance of modified epoxy resin composites using molecular dynamics (MD) simulations and experimental methods. Initially, various epoxy resin cross‐linking models are established through MD simulations to understand the influence of different nano ZnO contents on resin modification, further validated by experiments. Subsequently, the UV radiation resistance of nano ZnO–epoxy resin composites is assessed by subjecting them to high‐intensity UV radiation equivalent to 3 years of natural environmental conditions, analyzing changes in tensile properties, impact performance, hardness, and glass transition temperature of epoxy resin before and after UV radiation exposure. The findings suggest that the addition of nano zinc oxide reduces the impact of UV radiation on epoxy resin, with optimal UV radiation resistance observed at a nano zinc oxide mass fraction of 0.3 wt%.","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142219295","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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