V. Rodrigues, D. Hirayama, Antonio Carlos Ancelotti Junior
Abstract The curing reactions of epoxy resins are a complex process that defines thermosets final properties and are affected by any additive present on its formulation. Considering this, the aim of this study was to analyze the influence of the solvent addition on the curing kinetics of an epoxy system. The epoxy samples were prepared using different percentages by weight of acetone: 0, 2, 5 and 10 wt.%. From DSC and DMA tests, followed by the Borchardt-Daniels kinetic analysis it was reported that the addition of acetone can decrease the reactions rate, activation energy, Tg and elastic modulus. The presence of solvent, even in small amounts, can affect the curing mechanisms of epoxy resins. The changes on the curing behavior and the low quality of the final properties for the sample with 10 wt.% of solvent indicates that this may be a limit for acetone addition on the epoxy formulations.
{"title":"The effects of residual organic solvent on epoxy: modeling of kinetic parameters by DSC and Borchardt-Daniels method","authors":"V. Rodrigues, D. Hirayama, Antonio Carlos Ancelotti Junior","doi":"10.1590/0104-1428.09820","DOIUrl":"https://doi.org/10.1590/0104-1428.09820","url":null,"abstract":"Abstract The curing reactions of epoxy resins are a complex process that defines thermosets final properties and are affected by any additive present on its formulation. Considering this, the aim of this study was to analyze the influence of the solvent addition on the curing kinetics of an epoxy system. The epoxy samples were prepared using different percentages by weight of acetone: 0, 2, 5 and 10 wt.%. From DSC and DMA tests, followed by the Borchardt-Daniels kinetic analysis it was reported that the addition of acetone can decrease the reactions rate, activation energy, Tg and elastic modulus. The presence of solvent, even in small amounts, can affect the curing mechanisms of epoxy resins. The changes on the curing behavior and the low quality of the final properties for the sample with 10 wt.% of solvent indicates that this may be a limit for acetone addition on the epoxy formulations.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"83 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78956511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. V. Moura, Douglas da Cruz Sousa, E. M. Moura, E. C. E. Araújo, I. M. Sittolin
Abstract This work aimed to obtain thermoplastic starch composites (TPS) derived from starch and fibers of babassu coconut. The (TPS) was prepared with 40% plasticizer (glycerol). The fibers underwent chemical treatment of alkalinization and bleaching. SEM images and infrared spectra showed that wax, lignin, and hemicellulose were removed from the fiber surface. SEM images of TPS starch showed a smooth and uniform surface, whereas images of the TPSWF composite (washed fiber) showed voids between the fiber and the TPS. This phenomenon was not observed in the SEM images of the composites TPSAF (alkalized fiber) and TPSBF (bleached fiber). The tensile strength and elastic modulus of the composites were higher than the pure TPS matrix. Concerning elongation, composites underwent less elongation than TPS. The mechanical properties found for the TPSWF and TPSAF composites do not differ. However, the mechanical properties of the TPSBF composite were better than the properties of the other composites.
{"title":"New biodegradable composites from starch and fibers of the babassu coconut","authors":"C. V. Moura, Douglas da Cruz Sousa, E. M. Moura, E. C. E. Araújo, I. M. Sittolin","doi":"10.1590/0104-1428.09519","DOIUrl":"https://doi.org/10.1590/0104-1428.09519","url":null,"abstract":"Abstract This work aimed to obtain thermoplastic starch composites (TPS) derived from starch and fibers of babassu coconut. The (TPS) was prepared with 40% plasticizer (glycerol). The fibers underwent chemical treatment of alkalinization and bleaching. SEM images and infrared spectra showed that wax, lignin, and hemicellulose were removed from the fiber surface. SEM images of TPS starch showed a smooth and uniform surface, whereas images of the TPSWF composite (washed fiber) showed voids between the fiber and the TPS. This phenomenon was not observed in the SEM images of the composites TPSAF (alkalized fiber) and TPSBF (bleached fiber). The tensile strength and elastic modulus of the composites were higher than the pure TPS matrix. Concerning elongation, composites underwent less elongation than TPS. The mechanical properties found for the TPSWF and TPSAF composites do not differ. However, the mechanical properties of the TPSBF composite were better than the properties of the other composites.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"39 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87991466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Qualitative and quantitative measuring in water bodies, nuclear medicine, agriculture, and world oil production use tracers to monitor, evaluate and continuously improve their processes. The bibliometric information about the past and the future of artificial tracers, to monitor surface and groundwater by using sustainable biodegradable materials it will be important for future generation. To fulfil this purpose, bibliometric literature analysis has been considered as a solution to identify research areas that need to be improved. The results of this paper showed that even with the increase in research in biopolymers, and the use of artificial tracers, academic development is still not significant. The United States, China, and Germany are the top publishers in this field however, there is no country that constantly develops research in these areas concomitantly using biodegradable polymers. Because of that, this field could be further explored, globally using innovative techniques and materials for new tracers.
{"title":"Use of biodegradable polymer for development of environmental tracers: a bibliometric review","authors":"Adriana Marques, S. Luz","doi":"10.1590/0104-1428.00221","DOIUrl":"https://doi.org/10.1590/0104-1428.00221","url":null,"abstract":"Abstract Qualitative and quantitative measuring in water bodies, nuclear medicine, agriculture, and world oil production use tracers to monitor, evaluate and continuously improve their processes. The bibliometric information about the past and the future of artificial tracers, to monitor surface and groundwater by using sustainable biodegradable materials it will be important for future generation. To fulfil this purpose, bibliometric literature analysis has been considered as a solution to identify research areas that need to be improved. The results of this paper showed that even with the increase in research in biopolymers, and the use of artificial tracers, academic development is still not significant. The United States, China, and Germany are the top publishers in this field however, there is no country that constantly develops research in these areas concomitantly using biodegradable polymers. Because of that, this field could be further explored, globally using innovative techniques and materials for new tracers.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44262990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. V. Dutra, Weslany Silvério Neto, P. H. Araújo, C. Sayer, Brenno Amaro da Silveira Neto, Fabricio Machado
Abstract This work aims to study the cationic miniemulsion polymerization of styrene catalyzed by iron-containing imidazolium-based ionic liquids. The polystyrenes had very high number-average molar mass around 1300 kg mol-1 at 85 °C, molar-mass dispersity close to 2.0 and glass transition temperature higher than 102 °C with average particle diameter that remained practically unchanged during the reaction, indicating that the monomer droplets correspond to the polymerization locus. First-order kinetics up to a limit conversion, along with the increase in molar mass as the temperature decreases, styrene polymerization at low temperatures and catalyst inability to polymerize monomers that react exclusively via free radical and/or anionic polymerization, indicate the cationic nature of polymerization. 1H-NMR and 13C-NMR spectra suggested the formation of polystyrene, allowing for tacticity distribution quantification: 10% isotactic, 20% atactic and 70% syndiotactic configurations. TEM micrographs confirmed the formation of spherical polymer nanoparticles and the presence of catalysts in the polymer matrix.
摘要本工作旨在研究含铁咪唑基离子液体催化苯乙烯的阳离子微乳液聚合。在85℃时，聚苯乙烯的数-平均摩尔质量约为1300 kg mol-1，摩尔-质量分散度接近2.0，玻璃化转变温度高于102℃，平均粒径在反应过程中基本保持不变，表明单体液滴与聚合位点相对应。一级动力学直到极限转化，随着温度降低摩尔质量的增加，苯乙烯在低温下聚合，催化剂不能聚合单体，只能通过自由基和/或阴离子聚合反应，表明聚合的阳离子性质。1H-NMR和13C-NMR谱显示聚苯乙烯的形成，允许战术分布量化:10%等规构型，20%无规构型和70%同规构型。TEM显微照片证实了球形聚合物纳米颗粒的形成和聚合物基体中催化剂的存在。
{"title":"Cationic polymerization of styrene using iron-containing ionic liquid catalysts in an aqueous dispersed medium","authors":"G. V. Dutra, Weslany Silvério Neto, P. H. Araújo, C. Sayer, Brenno Amaro da Silveira Neto, Fabricio Machado","doi":"10.1590/0104-1428.04620","DOIUrl":"https://doi.org/10.1590/0104-1428.04620","url":null,"abstract":"Abstract This work aims to study the cationic miniemulsion polymerization of styrene catalyzed by iron-containing imidazolium-based ionic liquids. The polystyrenes had very high number-average molar mass around 1300 kg mol-1 at 85 °C, molar-mass dispersity close to 2.0 and glass transition temperature higher than 102 °C with average particle diameter that remained practically unchanged during the reaction, indicating that the monomer droplets correspond to the polymerization locus. First-order kinetics up to a limit conversion, along with the increase in molar mass as the temperature decreases, styrene polymerization at low temperatures and catalyst inability to polymerize monomers that react exclusively via free radical and/or anionic polymerization, indicate the cationic nature of polymerization. 1H-NMR and 13C-NMR spectra suggested the formation of polystyrene, allowing for tacticity distribution quantification: 10% isotactic, 20% atactic and 70% syndiotactic configurations. TEM micrographs confirmed the formation of spherical polymer nanoparticles and the presence of catalysts in the polymer matrix.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90010731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Banu, V. Madhavan, Dhanashekar Manickam, Chandramohan Devarajan
Abstract This paper investigates the stacking sequence of combined natural and synthetic fibres reinforced epoxy composites for better mechanical properties. The hybrid composites fabricated using vacuum assisted compression molding process with the natural and synthetic fibres layered in three different sequences such as type I, type II and type III where the synthetic fibers were placed alternatively. The ultimate tensile strength of composite type III was increased by 12% and 30% when compared to composite type I and type II respectively. The flexural test results showed that composite type III have better flexural strength 223 MPa which is 13% and 11% greater than composite type I and type II respectively. Overall, it can be declared that the composite type III shows better tensile, and flexural properties i.e., the composite with aloe vera and palmyra palm fibres have better wettability with the matrix when compared to bamboo fibre.
{"title":"Experimental investigation on stacking sequence of Kevlar and natural fibres/epoxy polymer composites","authors":"M. Banu, V. Madhavan, Dhanashekar Manickam, Chandramohan Devarajan","doi":"10.1590/0104-1428.04320","DOIUrl":"https://doi.org/10.1590/0104-1428.04320","url":null,"abstract":"Abstract This paper investigates the stacking sequence of combined natural and synthetic fibres reinforced epoxy composites for better mechanical properties. The hybrid composites fabricated using vacuum assisted compression molding process with the natural and synthetic fibres layered in three different sequences such as type I, type II and type III where the synthetic fibers were placed alternatively. The ultimate tensile strength of composite type III was increased by 12% and 30% when compared to composite type I and type II respectively. The flexural test results showed that composite type III have better flexural strength 223 MPa which is 13% and 11% greater than composite type I and type II respectively. Overall, it can be declared that the composite type III shows better tensile, and flexural properties i.e., the composite with aloe vera and palmyra palm fibres have better wettability with the matrix when compared to bamboo fibre.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48459331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Hayeemasae, S. Soontaranon, Mohamad Qulam Zaki Bin Mohamad Rasidi, A. Masa
Abstract Mastication reduced the molecular weight of natural rubber (NR). This would affect the tensile properties and strain-induced crystallization of the rubber vulcanizates due to the structural changes of the rubber molecules. In this study, influences of mastication time on tensile response, deformation-induced crystallization, and structural effects of crosslinked NR were investigated. The crystallization behavior and structural changes during stretching were studied by means of wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS). Increased mastication time significantly affected modulus at specified strain and upturn point of strain-induced crystallization of the crosslinked samples while the tensile strength was influenced slightly by mastication. During stretching, degree of crystallinity at given strain was found to decrease with increasing mastication time, while the crystallite size was reduced. Moreover, the size of crosslinked network structures induced by crosslinking also decreased slightly with increasing mastication time, as suggested by SAXS measurement.
{"title":"Tensile and structural properties of natural rubber vulcanizates with different mastication times","authors":"N. Hayeemasae, S. Soontaranon, Mohamad Qulam Zaki Bin Mohamad Rasidi, A. Masa","doi":"10.1590/0104-1428.09120","DOIUrl":"https://doi.org/10.1590/0104-1428.09120","url":null,"abstract":"Abstract Mastication reduced the molecular weight of natural rubber (NR). This would affect the tensile properties and strain-induced crystallization of the rubber vulcanizates due to the structural changes of the rubber molecules. In this study, influences of mastication time on tensile response, deformation-induced crystallization, and structural effects of crosslinked NR were investigated. The crystallization behavior and structural changes during stretching were studied by means of wide angle X-ray scattering (WAXS) and small angle X-ray scattering (SAXS). Increased mastication time significantly affected modulus at specified strain and upturn point of strain-induced crystallization of the crosslinked samples while the tensile strength was influenced slightly by mastication. During stretching, degree of crystallinity at given strain was found to decrease with increasing mastication time, while the crystallite size was reduced. Moreover, the size of crosslinked network structures induced by crosslinking also decreased slightly with increasing mastication time, as suggested by SAXS measurement.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43560477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. D. Marestoni, H. Barud, R. Gomes, Rebeca Priscila Flora Catarino, N. Hata, J. Ressutte, W. Spinosa
Abstract In the last decade, bacterial cellulose (BC) has received considerable attention around the world, including in Brazil. The unique properties of BC, such as mechanical stability, tensile strength, thermostability, crystallinity, purity and biocompatibility make it a promising candidate for commercial applications in different areas. This article provides a comprehensive synthesis of commercial applications and studies related to BC around the world and shows the importance and development of Brazilian research during the last decade. In this review we present an overview of BC structure, biosynthesis and possible applications of BC mainly in the food, electronics, bioengineering, cosmetics and biomedical areas. The most significant contributions of Brazilian researchers using BC have been carried out in the biomedical area. Despite the increase in BC reserch, Brazil also needs to develop strategies to expand the use and commercialization of BC products, for which government financial support is extremely necessary.
{"title":"Commercial and potential applications of bacterial cellulose in Brazil: ten years review","authors":"L. D. Marestoni, H. Barud, R. Gomes, Rebeca Priscila Flora Catarino, N. Hata, J. Ressutte, W. Spinosa","doi":"10.1590/0104-1428.09420","DOIUrl":"https://doi.org/10.1590/0104-1428.09420","url":null,"abstract":"Abstract In the last decade, bacterial cellulose (BC) has received considerable attention around the world, including in Brazil. The unique properties of BC, such as mechanical stability, tensile strength, thermostability, crystallinity, purity and biocompatibility make it a promising candidate for commercial applications in different areas. This article provides a comprehensive synthesis of commercial applications and studies related to BC around the world and shows the importance and development of Brazilian research during the last decade. In this review we present an overview of BC structure, biosynthesis and possible applications of BC mainly in the food, electronics, bioengineering, cosmetics and biomedical areas. The most significant contributions of Brazilian researchers using BC have been carried out in the biomedical area. Despite the increase in BC reserch, Brazil also needs to develop strategies to expand the use and commercialization of BC products, for which government financial support is extremely necessary.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"80 4","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72487832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandro Junior Vessoni Torres, G. B. Medeiros, F. Rosário, F. Yamashita, L. Mattoso, E. Corradini
Abstract Blends of zein and poly(vinyl alcohol) (PVAl) were processed in an internal mixer (150oC, 50 rpm) for 5-8 minutes. Glycerol and oleic acid were used as plasticizers. The mixtures obtained were then compression molded and further characterized by Fourier transform infrared spectroscopy (FTIR), water-absorption experiments, mechanical tests, and scanning electron microscopy (SEM). FTIR analysis indicated the existence of hydrogen bonding interactions between zein and PVAl. Tensile tests showed that the addition of PVAl increased the flexibility of the blends. The tensile strength ranged from 1.7 to 5.7 MPa, elongation at break ranged from 2.7 to 32% and Young’s modulus ranged from 433 to 7371 MPa. Water absorption at equilibrium decreased with increasing zein content, which favored a brittle behavior in the zein/PVAl. The blends were immiscible in the composition studied and the presence of voids indicated poor interfacial interaction between the polymers.
{"title":"Mechanical and water absorption properties and morphology of melt processed Zein/PVAl blends","authors":"Sandro Junior Vessoni Torres, G. B. Medeiros, F. Rosário, F. Yamashita, L. Mattoso, E. Corradini","doi":"10.1590/0104-1428.10619","DOIUrl":"https://doi.org/10.1590/0104-1428.10619","url":null,"abstract":"Abstract Blends of zein and poly(vinyl alcohol) (PVAl) were processed in an internal mixer (150oC, 50 rpm) for 5-8 minutes. Glycerol and oleic acid were used as plasticizers. The mixtures obtained were then compression molded and further characterized by Fourier transform infrared spectroscopy (FTIR), water-absorption experiments, mechanical tests, and scanning electron microscopy (SEM). FTIR analysis indicated the existence of hydrogen bonding interactions between zein and PVAl. Tensile tests showed that the addition of PVAl increased the flexibility of the blends. The tensile strength ranged from 1.7 to 5.7 MPa, elongation at break ranged from 2.7 to 32% and Young’s modulus ranged from 433 to 7371 MPa. Water absorption at equilibrium decreased with increasing zein content, which favored a brittle behavior in the zein/PVAl. The blends were immiscible in the composition studied and the presence of voids indicated poor interfacial interaction between the polymers.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"285 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76862732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Péricles Lopes Sant’Ana, J. Bortoleto, N. Cruz, E. Rangel, Steven Frederick Durrant, W. Schreiner
Abstract In this work we discuss the wettability, chemical composition, surface morphology and optical transmittance of polyvinyl chloride (PVC) samples treated by Plasma Immersion and by Plasma Immersion Ion Implantation. The total pressure of N2 or SF6 was 6.66 Pa, for treatments of 900 s, applied rf power of 25 and 100 W, and the substrate temperature was about 298 K. In PIII, high voltage pulses of -2400 V at a cycle time of 30 µs and a frequency of 300 Hz were used. The wettability of the samples was assessed via contact angle measurements, which indicated either hydrophilicity or hydrophobicity, depending on the plasma composition. X-ray Photoelectron Spectroscopic analysis confirmed strong fluorine attachment to the surface after treatments using SF6 plasmas, and the presence of oxygen after treatments using nitrogen plasmas. Atomic Force Microscopy images showed that the roughness Rrms, depends on the plasma conditions. Optical transmittance in the visible region, T (λ), was increased by plasma immersion. The greatest contact angle observed was 142o (PI cathode), while the highest roughness was 213.2 nm. The highest optical transmittance in the visible region was around to 90% (PI anode).
{"title":"Surface functionalization of polyvinyl chloride by plasma immersion techniques","authors":"Péricles Lopes Sant’Ana, J. Bortoleto, N. Cruz, E. Rangel, Steven Frederick Durrant, W. Schreiner","doi":"10.1590/0104-1428.06020","DOIUrl":"https://doi.org/10.1590/0104-1428.06020","url":null,"abstract":"Abstract In this work we discuss the wettability, chemical composition, surface morphology and optical transmittance of polyvinyl chloride (PVC) samples treated by Plasma Immersion and by Plasma Immersion Ion Implantation. The total pressure of N2 or SF6 was 6.66 Pa, for treatments of 900 s, applied rf power of 25 and 100 W, and the substrate temperature was about 298 K. In PIII, high voltage pulses of -2400 V at a cycle time of 30 µs and a frequency of 300 Hz were used. The wettability of the samples was assessed via contact angle measurements, which indicated either hydrophilicity or hydrophobicity, depending on the plasma composition. X-ray Photoelectron Spectroscopic analysis confirmed strong fluorine attachment to the surface after treatments using SF6 plasmas, and the presence of oxygen after treatments using nitrogen plasmas. Atomic Force Microscopy images showed that the roughness Rrms, depends on the plasma conditions. Optical transmittance in the visible region, T (λ), was increased by plasma immersion. The greatest contact angle observed was 142o (PI cathode), while the highest roughness was 213.2 nm. The highest optical transmittance in the visible region was around to 90% (PI anode).","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"48 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76327352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.1590/0104-1428.20210039
C. Viet, H. Ismail, A. Masa, N. Hayeemasae
{"title":"Silane-coupled kenaf fiber filled thermoplastic elastomer based on recycled high density polyethylene/natural rubber blends","authors":"C. Viet, H. Ismail, A. Masa, N. Hayeemasae","doi":"10.1590/0104-1428.20210039","DOIUrl":"https://doi.org/10.1590/0104-1428.20210039","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67120766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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