This research introduces a new approach using zeolite ZSM‐5 (Z) as formaldehyde (FA) scavenger in urea‐formaldehyde (UF) resins, while simultaneously investigating and comparing the structural influence of Z and bentonite (B) on different properties of UF composite. ZSM‐5 and bentonite were used to modify the in situ synthesized UF resin with a low formaldehyde/urea (FA/U) molar ratio (0.8), to reduce the free FA content in the UF resin. The fillers and modified UF composites were characterized using XRD, FTIR, TGA, DTG, and DTA. The surface of fillers and modified UF resins was observed using SEM. The content of free FA, determined by the sulfite method, for the sample UF/Z composite, was 0.06%, while for the sample UF/B composite was 0.18%. After acid hydrolysis, the content of released FA was similar for both modified resins (4.08% for UF/Z and 4.80% for UF/B). This slight difference indicates a better hydrolytic stability of UF/Z. Analysis of thermal stability showed that UF/Z starts to degrade at a higher temperature, which, together with the values of released FA, indicates that UF resin modified with ZSM‐5 is thermally and hydrolytically more stable compared to the UF/B composite. The obtained results suggest that ZSM‐5 with its microporous structure contributes better to improving the properties of UF resins than bentonite with its layered structure.HighlightsSynthesis of UF resins modified with ZSM‐5 and bentonite.New approach using ZSM‐5 as a formaldehyde scavenger.Comprehensive characterization of the fillers and modified UF resins.UF/Z resin has superior hydrolytic and thermal stability over UF/B resin.The microporous structure of ZSM‐5 enhances the properties of UF.
{"title":"Use of modifiers ZSM‐5 and bentonite enhancing the hydrolytic and thermal stability of urea‐formaldehyde composites","authors":"Mirjana Ristić, Suzana Samaržija‐Jovanović, Marija Krstić, Tijana Jovanović, Vojislav Jovanović, Gordana Marković, Milena Marinović‐Cincović","doi":"10.1002/vnl.22153","DOIUrl":"https://doi.org/10.1002/vnl.22153","url":null,"abstract":"<jats:label/>This research introduces a new approach using zeolite ZSM‐5 (Z) as formaldehyde (FA) scavenger in urea‐formaldehyde (UF) resins, while simultaneously investigating and comparing the structural influence of Z and bentonite (B) on different properties of UF composite. ZSM‐5 and bentonite were used to modify the in situ synthesized UF resin with a low formaldehyde/urea (FA/U) molar ratio (0.8), to reduce the free FA content in the UF resin. The fillers and modified UF composites were characterized using XRD, FTIR, TGA, DTG, and DTA. The surface of fillers and modified UF resins was observed using SEM. The content of free FA, determined by the sulfite method, for the sample UF/Z composite, was 0.06%, while for the sample UF/B composite was 0.18%. After acid hydrolysis, the content of released FA was similar for both modified resins (4.08% for UF/Z and 4.80% for UF/B). This slight difference indicates a better hydrolytic stability of UF/Z. Analysis of thermal stability showed that UF/Z starts to degrade at a higher temperature, which, together with the values of released FA, indicates that UF resin modified with ZSM‐5 is thermally and hydrolytically more stable compared to the UF/B composite. The obtained results suggest that ZSM‐5 with its microporous structure contributes better to improving the properties of UF resins than bentonite with its layered structure.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Synthesis of UF resins modified with ZSM‐5 and bentonite.</jats:list-item> <jats:list-item>New approach using ZSM‐5 as a formaldehyde scavenger.</jats:list-item> <jats:list-item>Comprehensive characterization of the fillers and modified UF resins.</jats:list-item> <jats:list-item>UF/Z resin has superior hydrolytic and thermal stability over UF/B resin.</jats:list-item> <jats:list-item>The microporous structure of ZSM‐5 enhances the properties of UF.</jats:list-item> </jats:list>","PeriodicalId":17473,"journal":{"name":"Journal of Vinyl and Additive Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Debora P. Schmitz, Beatriz S. Cunha, Bluma G. Soares
Clean scrap polyvinylidene fluoride (rPVDF) from industrial reject was compounded with ethylene vinyl acetate (EVA) copolymer and graphene nanoplatelets (GNP) to produce low cost and scalable conductive composites. The effect of the melt processing conditions (temperature, time, and rotor speed) on the electrical conductivity and microwave absorbing (MWA) properties was investigated. All systems presented co‐continuous morphology indicated by scanning electron microscopy (SEM) and selective extraction experiments. The preferential localization of GNP in the EVA phase was evidenced by selective extraction and thermogravimetric analysis (TGA). Higher conductivity value was observed for the composite processed at 210°C for 3 min at a rotor speed of 200 rpm. The MWA performance of monolayer and bilayer composite structures with 2 mm thickness was investigated in terms of minimum reflection loss (RL) and effective absorption bandwidth (EAB). The bilayer system provided the best MWA response with RL = − 43.1 dB (>99.99% of EM attenuation) when prepared at 190°C for 3 min at a rotor speed of 200 rpm. The ecological and environmental importance of finding new applications for plastic waste, and the low cost of the materials and processing make this composite an interesting candidate for MWA purpose.HighlightsPromising application of clean scrap polyvinylidene fluoride (PVDF) in microwave absorbing materials;Conductivity and absorbing performance are affected by processing conditions;Co‐continuous structure of rPVDF/EVA blend influenced by graphene nanoplatelets (GNP);Selective localization of GNP in EVA phase;Outstanding microwave absorption properties achieved with bi‐layer structure.
将工业废料中的清洁聚偏二氟乙烯（rPVDF）与乙烯-醋酸乙烯（EVA）共聚物和石墨烯纳米颗粒（GNP）复合，生产出低成本、可扩展的导电复合材料。研究了熔融加工条件（温度、时间和转子速度）对导电性和微波吸收（MWA）性能的影响。扫描电子显微镜（SEM）和选择性萃取实验表明，所有系统都呈现出共连续形态。选择性萃取和热重分析（TGA）证明了 GNP 在 EVA 相中的优先定位。在转子转速为 200 转/分钟、温度为 210 摄氏度、时间为 3 分钟的条件下处理的复合材料的电导率值更高。从最小反射损耗（RL）和有效吸收带宽（EAB）的角度研究了厚度为 2 毫米的单层和双层复合结构的 MWA 性能。在转子转速为 200 rpm、温度为 190°C 的条件下制备 3 分钟时，双层系统的 MWA 响应最佳，RL = - 43.1 dB（电磁衰减 99.99%）。亮点：清洁废旧聚偏二氟乙烯（PVDF）在微波吸收材料中的应用前景广阔；电导率和吸收性能受加工条件的影响；rPVDF/EVA 共混物的共连续结构受石墨烯纳米颗粒（GNP）的影响；GNP 在 EVA 相中的选择性定位；双层结构实现了出色的微波吸收性能。
{"title":"Effect of melt‐processing conditions on the electrical conductivity and microwave absorbing properties of composites based on clean scrap poly(vinylidene fluoride/ethylene vinyl acetate copolymer and graphene nanoplatelets","authors":"Debora P. Schmitz, Beatriz S. Cunha, Bluma G. Soares","doi":"10.1002/vnl.22156","DOIUrl":"https://doi.org/10.1002/vnl.22156","url":null,"abstract":"<jats:label/>Clean scrap polyvinylidene fluoride (rPVDF) from industrial reject was compounded with ethylene vinyl acetate (EVA) copolymer and graphene nanoplatelets (GNP) to produce low cost and scalable conductive composites. The effect of the melt processing conditions (temperature, time, and rotor speed) on the electrical conductivity and microwave absorbing (MWA) properties was investigated. All systems presented co‐continuous morphology indicated by scanning electron microscopy (SEM) and selective extraction experiments. The preferential localization of GNP in the EVA phase was evidenced by selective extraction and thermogravimetric analysis (TGA). Higher conductivity value was observed for the composite processed at 210°C for 3 min at a rotor speed of 200 rpm. The MWA performance of monolayer and bilayer composite structures with 2 mm thickness was investigated in terms of minimum reflection loss (RL) and effective absorption bandwidth (EAB). The bilayer system provided the best MWA response with RL = − 43.1 dB (>99.99% of EM attenuation) when prepared at 190°C for 3 min at a rotor speed of 200 rpm. The ecological and environmental importance of finding new applications for plastic waste, and the low cost of the materials and processing make this composite an interesting candidate for MWA purpose.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Promising application of clean scrap polyvinylidene fluoride (PVDF) in microwave absorbing materials;</jats:list-item> <jats:list-item>Conductivity and absorbing performance are affected by processing conditions;</jats:list-item> <jats:list-item>Co‐continuous structure of rPVDF/EVA blend influenced by graphene nanoplatelets (GNP);</jats:list-item> <jats:list-item>Selective localization of GNP in EVA phase;</jats:list-item> <jats:list-item>Outstanding microwave absorption properties achieved with bi‐layer structure.</jats:list-item> </jats:list>","PeriodicalId":17473,"journal":{"name":"Journal of Vinyl and Additive Technology","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The growing utilization of textiles raises concerns about the ecological hazards of textile production methods and discarded textiles. The recycling and reusing of waste cotton materials align with the sustainable development of society. In this study, sulfated cellulose was synthesized by sulfating waste cotton using a deep eutectic solvent (DES). After nanofibrillation with ultrasonication, sulfated cellulose nanocrystal (SCNC) with an average width of 10.83 nm and an average length of 129.40 nm was produced. The thermal properties of the synthesized SCNC were significantly enhanced compared to the pristine cellulose, with a notable reduction of 87.1% in the peak heat release rate, as well as an 86.6% reduction in the total heat release. Additionally, when utilized as a reinforcement in poly(vinyl alcohol) (PVA) films, SCNC demonstrated a substantial rise in yield strength (from 62.3 to 94.8 MPa) and Young's modulus (from 2.7 to 4.4 GPa) of the PVA films. Furthermore, the incorporation of SCNC into composites increased the thermal stability while maintaining the high transparency (with light transmission higher than 84%), which has good potential for application in the electronic packaging field.HighlightsSCNC were successfully prepared from waste cotton using DES.Extracted SCNC were characterized using TEM, FTIR, XRD, TGA and MCC.SCNC enhanced the yield strength and thermal stability of PVA composites.Transparent and mechanically robust PVA‐based nanocomposites were created.
{"title":"Sulfated cellulose nanocrystal isolated from waste cotton fabrics by deep eutectic solvent and its application in polymer nanocomposite films","authors":"Lebin Zhao, Yutong Zhang, Yu Pan, Chaohong Dong, Xiujuan Huang, Gangqiang Zhang, Kaitao Zhang","doi":"10.1002/vnl.22154","DOIUrl":"https://doi.org/10.1002/vnl.22154","url":null,"abstract":"<jats:label/>The growing utilization of textiles raises concerns about the ecological hazards of textile production methods and discarded textiles. The recycling and reusing of waste cotton materials align with the sustainable development of society. In this study, sulfated cellulose was synthesized by sulfating waste cotton using a deep eutectic solvent (DES). After nanofibrillation with ultrasonication, sulfated cellulose nanocrystal (SCNC) with an average width of 10.83 nm and an average length of 129.40 nm was produced. The thermal properties of the synthesized SCNC were significantly enhanced compared to the pristine cellulose, with a notable reduction of 87.1% in the peak heat release rate, as well as an 86.6% reduction in the total heat release. Additionally, when utilized as a reinforcement in poly(vinyl alcohol) (PVA) films, SCNC demonstrated a substantial rise in yield strength (from 62.3 to 94.8 MPa) and Young's modulus (from 2.7 to 4.4 GPa) of the PVA films. Furthermore, the incorporation of SCNC into composites increased the thermal stability while maintaining the high transparency (with light transmission higher than 84%), which has good potential for application in the electronic packaging field.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>SCNC were successfully prepared from waste cotton using DES.</jats:list-item> <jats:list-item>Extracted S<jats:ext-link xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"https://www.sciencedirect.com/topics/chemistry/cellulose-nanocrystals\">CNC</jats:ext-link> were characterized using TEM, FTIR, XRD, TGA and MCC.</jats:list-item> <jats:list-item>SCNC enhanced the yield strength and thermal stability of PVA composites.</jats:list-item> <jats:list-item>Transparent and mechanically robust PVA‐based nanocomposites were created.</jats:list-item> </jats:list>","PeriodicalId":17473,"journal":{"name":"Journal of Vinyl and Additive Technology","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142216073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Sathyamoorthy, Vijay Raghunathan, Sanjay Mavinkere Rangappa, Suchart Siengchin, D. Lenin Singaravelu
This study investigates the tribological impact of incorporating micaceous additives in copper‐free brake friction composites for automotive applications. Four brake pad formulations were created, each containing different amounts of muscovite and phlogopite, ranging from 0% to 10% by weight. A brake pad comparison was conducted by replacing mica with synthetic barites. The physical, thermal, mechanical, and chemical properties of the fabricated brake friction composite were examined. Tribological features were evaluated through inertia brake dynamometer testing following the JASO‐C‐406 schedule. Scanning electron microscope (SEM) analysis delved into contact plateau formations and back transfer patches on the brake pad's surfaces. Notably, phlogopite‐based pads exhibited enhanced thermal stability and efficient heat dissipation, contributing to sustained tribological performance. Overall, the comprehensive evaluation using the multiple objective optimization by ratio analysis (MOORA) method positioned phlogopite‐based brake pads as the optimal choice for optimized braking performances.HighlightsExploration of micaceous additives as an ingredient in brake friction composite.Phlogopite‐based brake pads showed better fade and recovery performance.Phlogopite‐based brake pads exhibited low pad wear and rotor wear.MOORA optimization positioned phlogopite‐based brake pads as the optimal choice.
{"title":"Exploring the tribological impact of micaceous additives in copper‐free automobile brake friction composites","authors":"G. Sathyamoorthy, Vijay Raghunathan, Sanjay Mavinkere Rangappa, Suchart Siengchin, D. Lenin Singaravelu","doi":"10.1002/vnl.22142","DOIUrl":"https://doi.org/10.1002/vnl.22142","url":null,"abstract":"<jats:label/>This study investigates the tribological impact of incorporating micaceous additives in copper‐free brake friction composites for automotive applications. Four brake pad formulations were created, each containing different amounts of muscovite and phlogopite, ranging from 0% to 10% by weight. A brake pad comparison was conducted by replacing mica with synthetic barites. The physical, thermal, mechanical, and chemical properties of the fabricated brake friction composite were examined. Tribological features were evaluated through inertia brake dynamometer testing following the JASO‐C‐406 schedule. Scanning electron microscope (SEM) analysis delved into contact plateau formations and back transfer patches on the brake pad's surfaces. Notably, phlogopite‐based pads exhibited enhanced thermal stability and efficient heat dissipation, contributing to sustained tribological performance. Overall, the comprehensive evaluation using the multiple objective optimization by ratio analysis (MOORA) method positioned phlogopite‐based brake pads as the optimal choice for optimized braking performances.Highlights<jats:list list-type=\"bullet\"> <jats:list-item>Exploration of micaceous additives as an ingredient in brake friction composite.</jats:list-item> <jats:list-item>Phlogopite‐based brake pads showed better fade and recovery performance.</jats:list-item> <jats:list-item>Phlogopite‐based brake pads exhibited low pad wear and rotor wear.</jats:list-item> <jats:list-item>MOORA optimization positioned phlogopite‐based brake pads as the optimal choice.</jats:list-item> </jats:list>","PeriodicalId":17473,"journal":{"name":"Journal of Vinyl and Additive Technology","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141742625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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