Poly(lactic acid) (PLA)/poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) blends are typically phase‐separated, and there is limited research on using graphene oxide (GO) as their matrix filler. PLA/PHBV/GO composites using 1, 3, or 5 wt% GO were prepared by melt mixing, after which their morphology and thermal properties were determined. All the components were hydrophilic (Contact angles less than 90°), and the wetting coefficient value of 3.52 suggested that GO would be dispersed in PLA during surface energy evaluations (SEES). Scanning electron microscopy (SEM) showed that PLA/PHBV blends are immiscible and phase‐separated; however, adding GO brought partial miscibility. Differential scanning calorimetry (DSC) showed that GO plasticized the polymers at lower contents (1 wt%) and inhibited their crystallization at higher contents (3 and 5 wt%). Fourier‐transform infrared spectroscopy (FTIR) measurements showed that a chemical interaction exists between GO and the polymers, and X‐ray diffraction (XRD) results confirmed that GO inhibited crystallization in the polymers at high contents. Adding GO to the polymers generally improved the thermal stability of PLA, verifying the affinity thereof during thermogravimetric (TGA) analyses. Merging of the thermal degradation steps implied that GO induced partial miscibility on polymers. Concurrently, the polymers thermally masked the GO to prolong its lifespan. Composites with 1 wt% GO were the optimal and ideal materials.HighlightsMelt mixed PLA/PHBV blends and their composites with GO as a filler.GO brought partial miscibility to the blends and favored the PLA phase.1 wt% GO contents provide optimal thermal and morphological properties.3 and 5 wt% GO contents form chemical bonds with the polymers.Initial GO loadings increase the crystallinity of the polymers.
聚乳酸（PLA）/聚（3-羟基丁酸-3-羟基戊酸）（PHBV）共混物通常是相分离的，而使用氧化石墨烯（GO）作为其基体填料的研究还很有限。我们通过熔融混合的方法制备了含有 1、3 或 5 wt% GO 的聚乳酸/PHBV/GO 复合材料，然后测定了它们的形态和热性能。所有成分都具有亲水性（接触角小于 90°），润湿系数值为 3.52，这表明在进行表面能评估（SEES）时，GO 会分散在聚乳酸中。扫描电子显微镜（SEM）显示，聚乳酸/PHBV 混合物是不相溶和相分离的；但是，添加 GO 后会产生部分相溶。差示扫描量热法（DSC）显示，GO 在聚合物中的含量较低（1 wt%）时会使聚合物塑化，而在聚合物中的含量较高（3 和 5 wt%）时则会抑制聚合物结晶。傅立叶变换红外光谱（FTIR）测量结果表明，GO 与聚合物之间存在化学作用，X 射线衍射（XRD）结果证实，GO 在聚合物中的含量较高时，会抑制聚合物的结晶。在聚合物中添加 GO 可普遍提高聚乳酸的热稳定性，这在热重分析（TGA）中得到了验证。热降解步骤的合并意味着 GO 诱导了聚合物的部分混溶性。同时，聚合物对 GO 进行热遮蔽，延长了其使用寿命。含有 1 wt% GO 的复合材料是最佳的理想材料。 亮点 以 GO 作为填料，熔融混合聚乳酸/PHBV 共混物及其复合材料。GO 带来了混合物的部分混溶性，并有利于聚乳酸相。1 wt% 的 GO 含量可提供最佳的热性能和形态性能。3 和 5 wt% 的 GO 含量可与聚合物形成化学键。最初的 GO 含量会增加聚合物的结晶度。
{"title":"Morphology and thermal properties of poly(lactic acid)/poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/graphene oxide polymeric composites","authors":"Lesia Sydney Mokoena, Julia Puseletso Mofokeng","doi":"10.1002/pen.26919","DOIUrl":"https://doi.org/10.1002/pen.26919","url":null,"abstract":"<jats:label/>Poly(lactic acid) (PLA)/poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) blends are typically phase‐separated, and there is limited research on using graphene oxide (GO) as their matrix filler. PLA/PHBV/GO composites using 1, 3, or 5 wt% GO were prepared by melt mixing, after which their morphology and thermal properties were determined. All the components were hydrophilic (Contact angles less than 90°), and the wetting coefficient value of 3.52 suggested that GO would be dispersed in PLA during surface energy evaluations (SEES). Scanning electron microscopy (SEM) showed that PLA/PHBV blends are immiscible and phase‐separated; however, adding GO brought partial miscibility. Differential scanning calorimetry (DSC) showed that GO plasticized the polymers at lower contents (1 wt%) and inhibited their crystallization at higher contents (3 and 5 wt%). Fourier‐transform infrared spectroscopy (FTIR) measurements showed that a chemical interaction exists between GO and the polymers, and X‐ray diffraction (XRD) results confirmed that GO inhibited crystallization in the polymers at high contents. Adding GO to the polymers generally improved the thermal stability of PLA, verifying the affinity thereof during thermogravimetric (TGA) analyses. Merging of the thermal degradation steps implied that GO induced partial miscibility on polymers. Concurrently, the polymers thermally masked the GO to prolong its lifespan. Composites with 1 wt% GO were the optimal and ideal materials.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Melt mixed PLA/PHBV blends and their composites with GO as a filler.</jats:list-item> <jats:list-item>GO brought partial miscibility to the blends and favored the PLA phase.</jats:list-item> <jats:list-item>1 wt% GO contents provide optimal thermal and morphological properties.</jats:list-item> <jats:list-item>3 and 5 wt% GO contents form chemical bonds with the polymers.</jats:list-item> <jats:list-item>Initial GO loadings increase the crystallinity of the polymers.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"27 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945712","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}
Polymeric nanocell foam is a promising material that faces manufacturing challenges. Producing sizable and thick foams for properties testing has been challenging. This study aims to scale up and understand the foaming mechanism of nanocellular foams by controlling the saturation temperature, pressure, and molecular weight distribution of the matrix to fine‐tune the glass transition temperature of the polymer/gas mixture. The hot‐press foamed samples possess a 100 × 70 × 6 ~ 8 mm3 dimension and a cell size of less than 200 nm. Bimodal structures can also be created by controlling the critical processing parameters. Introducing 37% microcells into unimodal nanocellular foam reduced the relative density from 0.29 to 0.19. The thermal conductivity of the foams was tuned by controlling the cell size distribution. Unimodal nanofoams have the lowest thermal conductivity for foams of the same density due to the Knudsen effect and tortuosity. The measured thermal conductivity is in agreement with theoretical models.HighlightsPMMA nanofoam with a dimension of 100 × 70 × 6–8 mm3 and cell size below 200 nm.The morphology of nanofoams was tuned to be unimodal and bimodal.The foam density of the bimodal nanofoams was lowered below 0.238 g/cm3.The thermal conductivity of foams was tuned by controlling the cell structure.
{"title":"Fabrication of flat and sizeable nanocellular polymethyl methacrylate (PMMA) foam with tunable thermal conductivity","authors":"Kiday Fiseha Gebremedhin, Solomon Dufera Tolcha, Shu‐Kai Yeh","doi":"10.1002/pen.26895","DOIUrl":"https://doi.org/10.1002/pen.26895","url":null,"abstract":"<jats:label/>Polymeric nanocell foam is a promising material that faces manufacturing challenges. Producing sizable and thick foams for properties testing has been challenging. This study aims to scale up and understand the foaming mechanism of nanocellular foams by controlling the saturation temperature, pressure, and molecular weight distribution of the matrix to fine‐tune the glass transition temperature of the polymer/gas mixture. The hot‐press foamed samples possess a 100 × 70 × 6 ~ 8 mm<jats:sup>3</jats:sup> dimension and a cell size of less than 200 nm. Bimodal structures can also be created by controlling the critical processing parameters. Introducing 37% microcells into unimodal nanocellular foam reduced the relative density from 0.29 to 0.19. The thermal conductivity of the foams was tuned by controlling the cell size distribution. Unimodal nanofoams have the lowest thermal conductivity for foams of the same density due to the Knudsen effect and tortuosity. The measured thermal conductivity is in agreement with theoretical models.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>PMMA nanofoam with a dimension of 100 × 70 × 6–8 mm<jats:sup>3</jats:sup> and cell size below 200 nm.</jats:list-item> <jats:list-item>The morphology of nanofoams was tuned to be unimodal and bimodal.</jats:list-item> <jats:list-item>The foam density of the bimodal nanofoams was lowered below 0.238 g/cm<jats:sup>3</jats:sup>.</jats:list-item> <jats:list-item>The thermal conductivity of foams was tuned by controlling the cell structure.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"41 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945790","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}
Compatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl2·2H2O). Modified PC/PMMA alloys exhibit single Tg, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO2 foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation.HighlightsTransesterification catalysts enhanced compatibility between PC and PMMA.Nanopore structures were successfully constructed in PC foams.Segment stretching was the main reason for the formation of nanopores.
使用酯交换催化剂（SnCl2-2H2O）改善了聚碳酸酯（PC）和聚甲基丙烯酸甲酯（PMMA）合金的相容性。改性后的聚碳酸酯/聚甲基丙烯酸甲酯合金显示出单一的 Tg，其在扫描电镜下的初始岛状相也转变为均匀的表面。此外，改性合金的透光率从原来的 40% 提高到了 85%。此外，在酯交换催化剂存在下，通过固态二氧化碳发泡制备了具有微孔和纳米孔结构的 PC/PMMA 合金和 PC 泡沫。PC 样品中存在明显的纳米细胞结构，但 PMMA 样品中没有发现相关的纳米结构。此外，还研究了发泡温度和片段结构对其发泡行为的影响。此外，还在特定温度下进行了单轴应力实验，以模拟发泡过程中的双轴应力，从而发现纳米孔的形成机理。因此，纳米细胞结构的概念将为下一代高性能隔热 PC 材料的开发指明方向。在 PC 泡沫中成功构建了纳米孔结构。分段拉伸是形成纳米孔的主要原因。
{"title":"Compatibilizing and foaming of PC/PMMA composites with nano‐cellular structures in the presence of transesterification catalyst","authors":"Lulu Zhang, Pengke Huang, Hao Zheng, Linqiong Xu, Wenge Zheng, Yongqing Zhao","doi":"10.1002/pen.26916","DOIUrl":"https://doi.org/10.1002/pen.26916","url":null,"abstract":"<jats:label/>Compatibility of polycarbonate (PC) and polymethyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (SnCl<jats:sub>2</jats:sub>·2H<jats:sub>2</jats:sub>O). Modified PC/PMMA alloys exhibit single <jats:italic>T</jats:italic><jats:sub>g</jats:sub>, and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro‐cellular and nano‐cellular structures were prepared by solid‐state CO<jats:sub>2</jats:sub> foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano‐cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano‐cellular structures will point out a direction for the development of high‐performance, heat insulation PC materials of the next generation.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Transesterification catalysts enhanced compatibility between PC and PMMA.</jats:list-item> <jats:list-item>Nanopore structures were successfully constructed in PC foams.</jats:list-item> <jats:list-item>Segment stretching was the main reason for the formation of nanopores.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"26 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945796","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}
Bharath Govind, Sunita Rattan, Bruno Ameduri, Prachi Singhal, Ankit Tyagi, Eric W. Cochran
Solid polymer electrolyte membranes are considered as the nub of many electrochemical devices. Given the climate crisis and related concerns, the evolution of new membrane materials to support the sustainable systems is inevitable. Building on recent advances with the radiation technique and polymer chemistry, herein, anion exchange membranes (AEMs), ETFE‐g‐1VIm/4VP, were fabricated through graft copolymerization of vinyl heterocyclic monomer binary mixture, such as 1‐vinylimidazole (1‐VIm) and 4‐vinylpyridine (4‐VP) onto ethylene tetrafluoroethylene (ETFE), a main polymer backbone without aryl ether bonds. The grafting reaction was achieved at 60°C and then followed by quaternization as a subsequent step. The effects of various reaction grafting conditions were investigated. The ETFE‐g‐1VIm/4VP AEM were characterized w.r.t the morphological and structural features. The dense surface of the grafted membranes is proved by field emission‐scanning electron microscopy (FE‐SEM) images, which also show that the vinyl entities are clearly distributed in the prepolymer, which may lead to a continuous ion transport channel. AEMs processed from the highest graft yield showed good hydroxide conductivity at 90°C, reaching 16.9 mS/cm due to the presence of more transport sites. The same membrane has a relatively good alkaline stability, which is studied through weight percentage method and FT‐IR. Hence, we assume that the introduction of multi‐cationic moieties, pyridinium and imidazolium, contributes to the performance of anion exchange membranes and makes a perfect balance, especially the hydrophilicity and hydrophobicity. These data highlight the potential of the copolymer as an anion exchange membrane for wide spectra of electrochemical applications.HighlightsAEMs based on ETFE‐g‐1VIm/4VP are developed via radiation grafting.The membrane exhibits remarkable alkaline stability.FT‐IR, SEM, and weight percentage methods were used to prove the alkaline stability.The membrane has the potential to be used for different electrochemical applications.
{"title":"Anion exchange membrane with enhanced alkaline stability through radiation grafting of ETFE for solid polymer electrolytes","authors":"Bharath Govind, Sunita Rattan, Bruno Ameduri, Prachi Singhal, Ankit Tyagi, Eric W. Cochran","doi":"10.1002/pen.26907","DOIUrl":"https://doi.org/10.1002/pen.26907","url":null,"abstract":"<jats:label/>Solid polymer electrolyte membranes are considered as the nub of many electrochemical devices. Given the climate crisis and related concerns, the evolution of new membrane materials to support the sustainable systems is inevitable. Building on recent advances with the radiation technique and polymer chemistry, herein, anion exchange membranes (AEMs), ETFE‐<jats:italic>g</jats:italic>‐1VIm/4VP, were fabricated through graft copolymerization of vinyl heterocyclic monomer binary mixture, such as 1‐vinylimidazole (1‐VIm) and 4‐vinylpyridine (4‐VP) onto ethylene tetrafluoroethylene (ETFE), a main polymer backbone without aryl ether bonds. The grafting reaction was achieved at 60°C and then followed by quaternization as a subsequent step. The effects of various reaction grafting conditions were investigated. The ETFE‐<jats:italic>g</jats:italic>‐1VIm/4VP AEM were characterized w.r.t the morphological and structural features. The dense surface of the grafted membranes is proved by field emission‐scanning electron microscopy (FE‐SEM) images, which also show that the vinyl entities are clearly distributed in the prepolymer, which may lead to a continuous ion transport channel. AEMs processed from the highest graft yield showed good hydroxide conductivity at 90°C, reaching 16.9 mS/cm due to the presence of more transport sites. The same membrane has a relatively good alkaline stability, which is studied through weight percentage method and FT‐IR. Hence, we assume that the introduction of multi‐cationic moieties, pyridinium and imidazolium, contributes to the performance of anion exchange membranes and makes a perfect balance, especially the hydrophilicity and hydrophobicity. These data highlight the potential of the copolymer as an anion exchange membrane for wide spectra of electrochemical applications.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>AEMs based on ETFE‐g‐1VIm/4VP are developed via radiation grafting.</jats:list-item> <jats:list-item>The membrane exhibits remarkable alkaline stability.</jats:list-item> <jats:list-item>FT‐IR, SEM, and weight percentage methods were used to prove the alkaline stability.</jats:list-item> <jats:list-item>The membrane has the potential to be used for different electrochemical applications.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"93 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945793","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}
Thu Ha Le, Duc Anh Dinh, My Tra Le, Thang Van Le, Van‐Tien Bui
The widespread use of single‐use plastic food wrapping and drinking straws has led to significant plastic and microplastic pollution, threatening environmental sustainability and human health. This study aims to provide sustainable alternatives by improving starch‐based biofilms' mechanical properties and water resistance for food wrapping and edible drinking straws. We modified starch with chitosan, raw seaweed, and sodium tripolyphosphate (STPP) to enhance these biofilms. Our results show that the optimal proportion of chitosan, combined with varying seaweed and STPP content, significantly improves the biofilms' properties. The developed starch‐based biofilms offer an eco‐friendly and sustainable alternative to single‐use plastic, with the potential for large‐scale, cost‐effective production.HighlightsNovel edible starch‐based biofilms were successfully prepared.The biofilms made from renewable FDA‐approved edible materials.Biofilms showed improved mechanical properties and water resistance.The biofilms exhibited non‐toxic and antimicrobial properties.Biofilms offer alternatives to single‐use plastic for food wrapping.
{"title":"Enhancing water resistance and mechanical properties of starch‐based edible biofilms through chitosan, seaweed, and sodium tripolyphosphate modifications","authors":"Thu Ha Le, Duc Anh Dinh, My Tra Le, Thang Van Le, Van‐Tien Bui","doi":"10.1002/pen.26911","DOIUrl":"https://doi.org/10.1002/pen.26911","url":null,"abstract":"<jats:label/>The widespread use of single‐use plastic food wrapping and drinking straws has led to significant plastic and microplastic pollution, threatening environmental sustainability and human health. This study aims to provide sustainable alternatives by improving starch‐based biofilms' mechanical properties and water resistance for food wrapping and edible drinking straws. We modified starch with chitosan, raw seaweed, and sodium tripolyphosphate (STPP) to enhance these biofilms. Our results show that the optimal proportion of chitosan, combined with varying seaweed and STPP content, significantly improves the biofilms' properties. The developed starch‐based biofilms offer an eco‐friendly and sustainable alternative to single‐use plastic, with the potential for large‐scale, cost‐effective production.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Novel edible starch‐based biofilms were successfully prepared.</jats:list-item> <jats:list-item>The biofilms made from renewable FDA‐approved edible materials.</jats:list-item> <jats:list-item>Biofilms showed improved mechanical properties and water resistance.</jats:list-item> <jats:list-item>The biofilms exhibited non‐toxic and antimicrobial properties.</jats:list-item> <jats:list-item>Biofilms offer alternatives to single‐use plastic for food wrapping.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"6 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945792","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}
Ke Li, Lin Yang, Lin Yang, Liu He, Juan Du, Xinyue Li
A low dielectric polyimide/polyimide microsphere (PI/PM) composite film was constructed by thermal imidization of polyamic acid from pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA) in the presence of porous PM. The PM particles with particle size of about 2 μm were prepared via the solvothermal method using 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and ODA as monomers through thermal imidization. Due to the favorable compatibility between the porous PM and PI matrix, the mechanical properties, thermal stability, and dielectric properties of the obtained composite films were significantly improved. The PI/PM composite films had a tensile strength of 44.18–64.32 MPa, and the corresponding elongation at break of 6.21%–11.7%. Furthermore, the thermogravimetric temperatures of T5% were 538.9–563.7°C. The dielectric constants of the composite films at 1 MHz were 2.59–3.68, and the corresponding dielectric loss were only 0.0119–0.00405. Thus, the combination of excellent mechanical properties, high thermal stability, extremely low dielectric constant, and dielectric loss make the composite films ideal for deployment as high‐performance materials for 5G applications.HighlightsLow dielectric polyimide composite film was prepared by thermal imidization of polyamic acid in the presence of porous polyimide microspheres.Porous polyimide microspheres were prepared by thermal using the imidization solvothermal method.Low dielectric polyimide composite film with good comprehensive properties.
{"title":"Low dielectric polyimide microsphere/polyimide composite films based on porous polyimide microsphere","authors":"Ke Li, Lin Yang, Lin Yang, Liu He, Juan Du, Xinyue Li","doi":"10.1002/pen.26910","DOIUrl":"https://doi.org/10.1002/pen.26910","url":null,"abstract":"<jats:label/>A low dielectric polyimide/polyimide microsphere (PI/PM) composite film was constructed by thermal imidization of polyamic acid from pyromellitic dianhydride (PMDA) and 4,4′‐oxydianiline (ODA) in the presence of porous PM. The PM particles with particle size of about 2 μm were prepared via the solvothermal method using 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and ODA as monomers through thermal imidization. Due to the favorable compatibility between the porous PM and PI matrix, the mechanical properties, thermal stability, and dielectric properties of the obtained composite films were significantly improved. The PI/PM composite films had a tensile strength of 44.18–64.32 MPa, and the corresponding elongation at break of 6.21%–11.7%. Furthermore, the thermogravimetric temperatures of <jats:italic>T</jats:italic><jats:sub>5%</jats:sub> were 538.9–563.7°C. The dielectric constants of the composite films at 1 MHz were 2.59–3.68, and the corresponding dielectric loss were only 0.0119–0.00405. Thus, the combination of excellent mechanical properties, high thermal stability, extremely low dielectric constant, and dielectric loss make the composite films ideal for deployment as high‐performance materials for 5G applications.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Low dielectric polyimide composite film was prepared by thermal imidization of polyamic acid in the presence of porous polyimide microspheres.</jats:list-item> <jats:list-item>Porous polyimide microspheres were prepared by thermal using the imidization solvothermal method.</jats:list-item> <jats:list-item>Low dielectric polyimide composite film with good comprehensive properties.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"20 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945794","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}
Yusheng Xiao, Fan Zhang, Renbing Wei, Dong Qin, Zhaohua Tang, Yu Bao, Zhenbing Cai
Fluoroelastomer (FKM) undergo various degrees of degradation in a gamma‐irradiated environment, leading to changes in their mechanical and tribological properties. In this paper, changes in the properties of FKM were investigated for six different doses. Fourier transform infrared‐atomic absorption spectroscopy (FTIR‐ATR) results show that FKM samples undergo dehydrofluorination and oxidation reactions during irradiation, resulting in the formation of C=C, C=O, and ‐OH functional groups. The results of the swelling test showed that the degree of cross‐linking of the FKM specimens increased with increasing irradiation dose. Mechanical test results show that the fracture mechanism of FKM specimens gradually evolves from ductile fracture to brittle fracture with the increase of irradiation dose. Its tensile strength reaches its maximum at an irradiation dose of 1000 kGy, and the modulus of elasticity becomes larger with increasing irradiation dose. The results of wear tests show that the average coefficient of friction of FKM specimens first decreases, reaches a minimum at 500 kGy, and then gradually increases. The amount of wear increases with increasing irradiation dose. The wear mechanism of FKM specimens is abrasive wear at 0–500 kGy, adhesive wear at 1000 and 2000 kGy, and fatigue wear at 3000 kGy.HighlightsFKM was irradiated by gamma‐ray with a total dose of 3000 kGy.Dehydrofluorination and oxidation reactions occur during irradiation.Increased cross‐linking leads to changes in mechanical properties.The wear mechanism of FKM with different doses has been investigated.
{"title":"Influence of γ‐irradiation dose on the mechanical and tribological properties of fluoroelastomer","authors":"Yusheng Xiao, Fan Zhang, Renbing Wei, Dong Qin, Zhaohua Tang, Yu Bao, Zhenbing Cai","doi":"10.1002/pen.26912","DOIUrl":"https://doi.org/10.1002/pen.26912","url":null,"abstract":"<jats:label/>Fluoroelastomer (FKM) undergo various degrees of degradation in a gamma‐irradiated environment, leading to changes in their mechanical and tribological properties. In this paper, changes in the properties of FKM were investigated for six different doses. Fourier transform infrared‐atomic absorption spectroscopy (FTIR‐ATR) results show that FKM samples undergo dehydrofluorination and oxidation reactions during irradiation, resulting in the formation of C=C, C=O, and ‐OH functional groups. The results of the swelling test showed that the degree of cross‐linking of the FKM specimens increased with increasing irradiation dose. Mechanical test results show that the fracture mechanism of FKM specimens gradually evolves from ductile fracture to brittle fracture with the increase of irradiation dose. Its tensile strength reaches its maximum at an irradiation dose of 1000 kGy, and the modulus of elasticity becomes larger with increasing irradiation dose. The results of wear tests show that the average coefficient of friction of FKM specimens first decreases, reaches a minimum at 500 kGy, and then gradually increases. The amount of wear increases with increasing irradiation dose. The wear mechanism of FKM specimens is abrasive wear at 0–500 kGy, adhesive wear at 1000 and 2000 kGy, and fatigue wear at 3000 kGy.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>FKM was irradiated by gamma‐ray with a total dose of 3000 kGy.</jats:list-item> <jats:list-item>Dehydrofluorination and oxidation reactions occur during irradiation.</jats:list-item> <jats:list-item>Increased cross‐linking leads to changes in mechanical properties.</jats:list-item> <jats:list-item>The wear mechanism of FKM with different doses has been investigated.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"48 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945821","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}
David O. Kazmer, Sixtus O. Nzeh, Beijun Shen, David C. Elbert, Ramaswamy Nagarajan, Margaret Sobkowicz‐Kline, Thao D. Nguyen
This study aims to establish a systematic approach for characterizing recycled polyolefins of unknown composition, with a specific focus on predicting their performance in film extrusion. We explore various characterization techniques, including differential scanning calorimetry (DSC), Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and rheometry to assess their effectiveness in identifying the polyethylene (PE) fractions within polypropylene (PP) recyclates. By integrating experimental data with modeling techniques, we aim to provide insights into the predictive capabilities of these techniques in determining processing behaviors. The research highlights the superior fidelity of DSC in predicting the relative fraction and type of PE in a PP recyclate. FTIR is also identified as a high‐fidelity approach, albeit requiring application‐specific calibration. TGA, capillary, and oscillatory rheometry are recognized for their ability to distinguish between grades of recycled polyolefins but provide aggregate behaviors rather than detailed constituent information. 3D flow simulation of the cast film extrusion investigated the effect of the viscosity characterization method, non‐isothermal assumption, and process settings but could not fully replicate the observed variations in the cast film processing of two industrial polyolefins with similar melt flow rates and viscosity behaviors. This underscores the practical challenge of predicting processing issues prior to actual processing, necessitating reliance on reliable instrumentation suites and human expertise for diagnosing and remedying variations.HighlightsTwo industrial recycled polypropylene materials having similar melt flow rates exhibit drastically different cast film processing behaviors.DSC and FTIR provide reasonable approaches for identifying constituent materials.Modeling of the melt viscosities characterized by capillary and parallel plate rheology suggests that viscosity variations relative to the power‐law behavior assumed in the coat hanger die design is a predominant driver of cast film instabilities.
{"title":"Characterization, processing, and modeling of industrial recycled polyolefins","authors":"David O. Kazmer, Sixtus O. Nzeh, Beijun Shen, David C. Elbert, Ramaswamy Nagarajan, Margaret Sobkowicz‐Kline, Thao D. Nguyen","doi":"10.1002/pen.26882","DOIUrl":"https://doi.org/10.1002/pen.26882","url":null,"abstract":"<jats:label/>This study aims to establish a systematic approach for characterizing recycled polyolefins of unknown composition, with a specific focus on predicting their performance in film extrusion. We explore various characterization techniques, including differential scanning calorimetry (DSC), Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and rheometry to assess their effectiveness in identifying the polyethylene (PE) fractions within polypropylene (PP) recyclates. By integrating experimental data with modeling techniques, we aim to provide insights into the predictive capabilities of these techniques in determining processing behaviors. The research highlights the superior fidelity of DSC in predicting the relative fraction and type of PE in a PP recyclate. FTIR is also identified as a high‐fidelity approach, albeit requiring application‐specific calibration. TGA, capillary, and oscillatory rheometry are recognized for their ability to distinguish between grades of recycled polyolefins but provide aggregate behaviors rather than detailed constituent information. 3D flow simulation of the cast film extrusion investigated the effect of the viscosity characterization method, non‐isothermal assumption, and process settings but could not fully replicate the observed variations in the cast film processing of two industrial polyolefins with similar melt flow rates and viscosity behaviors. This underscores the practical challenge of predicting processing issues prior to actual processing, necessitating reliance on reliable instrumentation suites and human expertise for diagnosing and remedying variations.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Two industrial recycled polypropylene materials having similar melt flow rates exhibit drastically different cast film processing behaviors.</jats:list-item> <jats:list-item>DSC and FTIR provide reasonable approaches for identifying constituent materials.</jats:list-item> <jats:list-item>Modeling of the melt viscosities characterized by capillary and parallel plate rheology suggests that viscosity variations relative to the power‐law behavior assumed in the coat hanger die design is a predominant driver of cast film instabilities.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"373 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945795","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}
Shanu Prabhakar, Jitendra Pratap Singh, Kamal Kumar, Shiv Govind Prasad, Debmalya Roy
We have designed and developed nonwoven fabric supported electrospun polymeric nanofibrous‐based membrane for robust filtration system for ecological sustainability of clean water. The fabricated nanocomposites filters were tested for the removal of chromium (VI) toxic heavy metal ions from contaminated feedstock water. The interpenetrating network like morphological structure obtained from pure and composite nanofibers‐based membranes have been thoroughly investigated to understand the structure–properties of highly entangled system. It has been found that incorporating functional moieties onto nanocomposite membranes significantly impacts the absorption efficiency of toxic metals. The pore sizes of the hierarchical geometries have been varied to insight into its impact on flow rate and efficiency of filtration. The strategy of interfacing the multifunctional composite polyethylene terephthalate nanofiber membrane supported on nonwoven fabric to generate heterostructures has found to provide mechanically stable platform for efficient metal ion removal. It has been found by BET surface area analysis that the nanofibers reinforced with functional nanomaterials has controlled pore geometry compared to pristine PET electrospun nanofibers which lead to higher absorption of metal ions. We have highlighted the importance of mechanically stable electrospun polymeric nanofibers membrane‐based mitigation strategies to meet the huge demand of potable water for long‐term environmental sustainability.HighlightsMechanically toughened freestanding nanofibers mat supported on nonwoven fabric.Functionally upgrade nanofibers by incorporation of carbon based nanofillers.Controlled porosity by morphological optimization for removal of contaminates.
我们设计并开发了以电纺聚合物纳米纤维为基础的无纺布膜，这种膜具有强大的过滤系统，可实现清洁水源的生态可持续性。我们对制造的纳米复合过滤器进行了测试，以去除受污染原料水中的铬（VI）有毒重金属离子。对纯纳米纤维膜和复合纳米纤维膜的互穿网络形态结构进行了深入研究，以了解高度纠缠系统的结构特性。研究发现，在纳米复合膜上加入功能分子会显著影响有毒金属的吸收效率。我们改变了分层几何结构的孔径大小，以深入了解其对流速和过滤效率的影响。研究发现，将多功能复合聚对苯二甲酸乙二酯纳米纤维膜与无纺布连接以产生异质结构的策略为高效去除金属离子提供了机械稳定的平台。通过 BET 表面积分析发现，与原始 PET 电纺纳米纤维相比，用功能纳米材料增强的纳米纤维具有可控的孔隙几何形状，这导致了更高的金属离子吸收率。我们强调了基于机械稳定性电纺聚合物纳米纤维膜的缓解策略的重要性，以满足饮用水的巨大需求，实现环境的长期可持续性。通过加入碳基纳米填料实现纳米纤维的功能升级。通过形态优化控制孔隙率，以去除污染物。
{"title":"Chromium adsorption efficiency by functional polymeric nanocomposite membrane: A case study for environmental sustainability","authors":"Shanu Prabhakar, Jitendra Pratap Singh, Kamal Kumar, Shiv Govind Prasad, Debmalya Roy","doi":"10.1002/pen.26880","DOIUrl":"https://doi.org/10.1002/pen.26880","url":null,"abstract":"<jats:label/>We have designed and developed nonwoven fabric supported electrospun polymeric nanofibrous‐based membrane for robust filtration system for ecological sustainability of clean water. The fabricated nanocomposites filters were tested for the removal of chromium (VI) toxic heavy metal ions from contaminated feedstock water. The interpenetrating network like morphological structure obtained from pure and composite nanofibers‐based membranes have been thoroughly investigated to understand the structure–properties of highly entangled system. It has been found that incorporating functional moieties onto nanocomposite membranes significantly impacts the absorption efficiency of toxic metals. The pore sizes of the hierarchical geometries have been varied to insight into its impact on flow rate and efficiency of filtration. The strategy of interfacing the multifunctional composite polyethylene terephthalate nanofiber membrane supported on nonwoven fabric to generate heterostructures has found to provide mechanically stable platform for efficient metal ion removal. It has been found by BET surface area analysis that the nanofibers reinforced with functional nanomaterials has controlled pore geometry compared to pristine PET electrospun nanofibers which lead to higher absorption of metal ions. We have highlighted the importance of mechanically stable electrospun polymeric nanofibers membrane‐based mitigation strategies to meet the huge demand of potable water for long‐term environmental sustainability.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Mechanically toughened freestanding nanofibers mat supported on nonwoven fabric.</jats:list-item> <jats:list-item>Functionally upgrade nanofibers by incorporation of carbon based nanofillers.</jats:list-item> <jats:list-item>Controlled porosity by morphological optimization for removal of contaminates.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"84 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945822","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}
Deepak Mudakavi, Karunya G, Patel Varsha, Somashekara M Adinarayanappa
Material extrusion‐based additive manufacturing (AM) process builds the objects/structures through a precise feedstock deposition in a layer‐by‐layer manner. Polylactic acid (PLA) is a popular biodegradable feedstock in AM, while octyl methoxycinnamate (OMC) is known for its eco‐friendliness and ultraviolet (UV) protection properties. The present study focuses on the novel infusion methodology of OMC‐based microcapsules into PLA to develop self‐healing composite filaments. Post‐composition iterations, the optimum compositions for the filler and plasticizer were determined, and the filaments were extruded. Microcapsule‐infused PLA and the neat PLA samples were printed as per the American Society for Testing and Materials (ASTM) standard. The uniaxial tensile test results showed that the failure strain endured by the microcapsule‐infused samples was about 10 times more than the neat PLA counterparts. It is attributed to the effective load distribution and the complex polymerization reaction (due to the interaction of OMC with the matrix). Fracture surface morphology of the samples via optical microscopy (OM) and field emission scanning electron microscope (FESEM) affirmed the strong PLA‐OMC interface. A depreciation in the Brinell Hardness for the microcapsule‐based samples was due to the localized indenter force, causing greater damage in a narrow area than microcapsule ruptures' healing ability.HighlightsThe optimized composition of PLA: plasticizer:microcapsule is 1:0.04:0.05.Microcapsule‐infused PLA has improved Young's modulus and failure strain.Interaction with microcapsules improves elastic behavior and self‐healing.FESEM reveals close bonding of microcapsule with the PLA matrix.
{"title":"Synthesis and characterization of additively manufactured microcapsule‐reinforced polylactic acid composites for autonomous self‐healing","authors":"Deepak Mudakavi, Karunya G, Patel Varsha, Somashekara M Adinarayanappa","doi":"10.1002/pen.26903","DOIUrl":"https://doi.org/10.1002/pen.26903","url":null,"abstract":"<jats:label/>Material extrusion‐based additive manufacturing (AM) process builds the objects/structures through a precise feedstock deposition in a layer‐by‐layer manner. Polylactic acid (PLA) is a popular biodegradable feedstock in AM, while octyl methoxycinnamate (OMC) is known for its eco‐friendliness and ultraviolet (UV) protection properties. The present study focuses on the novel infusion methodology of OMC‐based microcapsules into PLA to develop self‐healing composite filaments. Post‐composition iterations, the optimum compositions for the filler and plasticizer were determined, and the filaments were extruded. Microcapsule‐infused PLA and the neat PLA samples were printed as per the American Society for Testing and Materials (ASTM) standard. The uniaxial tensile test results showed that the failure strain endured by the microcapsule‐infused samples was about 10 times more than the neat PLA counterparts. It is attributed to the effective load distribution and the complex polymerization reaction (due to the interaction of OMC with the matrix). Fracture surface morphology of the samples via optical microscopy (OM) and field emission scanning electron microscope (FESEM) affirmed the strong PLA‐OMC interface. A depreciation in the Brinell Hardness for the microcapsule‐based samples was due to the localized indenter force, causing greater damage in a narrow area than microcapsule ruptures' healing ability.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>The optimized composition of PLA: plasticizer:microcapsule is 1:0.04:0.05.</jats:list-item> <jats:list-item>Microcapsule‐infused PLA has improved Young's modulus and failure strain.</jats:list-item> <jats:list-item>Interaction with microcapsules improves elastic behavior and self‐healing.</jats:list-item> <jats:list-item>FESEM reveals close bonding of microcapsule with the PLA matrix.</jats:list-item> </jats:list>","PeriodicalId":20281,"journal":{"name":"Polymer Engineering and Science","volume":"93 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945825","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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