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The effects of residual organic solvent on epoxy: modeling of kinetic parameters by DSC and Borchardt-Daniels method 残余有机溶剂对环氧树脂的影响:DSC和Borchardt-Daniels法的动力学参数建模
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-28 DOI: 10.1590/0104-1428.09820
V. Rodrigues, D. Hirayama, Antonio Carlos Ancelotti Junior
{"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}
引用次数: 0
New biodegradable composites from starch and fibers of the babassu coconut 由巴巴苏椰子淀粉和纤维制成的新型可生物降解复合材料
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-28 DOI: 10.1590/0104-1428.09519
C. V. Moura, Douglas da Cruz Sousa, E. M. Moura, E. C. E. Araújo, I. M. Sittolin
{"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}
引用次数: 8
Use of biodegradable polymer for development of environmental tracers: a bibliometric review 利用可生物降解聚合物开发环境示踪剂:文献计量学综述
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-28 DOI: 10.1590/0104-1428.00221
Adriana Marques, S. Luz
{"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}
引用次数: 4
Cationic polymerization of styrene using iron-containing ionic liquid catalysts in an aqueous dispersed medium 用含铁离子液体催化剂在水分散介质中进行苯乙烯阳离子聚合
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-21 DOI: 10.1590/0104-1428.04620
G. V. Dutra, Weslany Silvério Neto, P. H. Araújo, C. Sayer, Brenno Amaro da Silveira Neto, Fabricio Machado
{"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}
引用次数: 2
Experimental investigation on stacking sequence of Kevlar and natural fibres/epoxy polymer composites 芳纶与天然纤维/环氧聚合物复合材料堆积顺序的实验研究
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-10 DOI: 10.1590/0104-1428.04320
M. Banu, V. Madhavan, Dhanashekar Manickam, Chandramohan Devarajan
{"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}
引用次数: 3
Tensile and structural properties of natural rubber vulcanizates with different mastication times 不同咀嚼时间天然橡胶硫化胶的拉伸和结构性能
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-05-10 DOI: 10.1590/0104-1428.09120
N. Hayeemasae, S. Soontaranon, Mohamad Qulam Zaki Bin Mohamad Rasidi, A. Masa
{"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}
引用次数: 3
Commercial and potential applications of bacterial cellulose in Brazil: ten years review 巴西细菌纤维素的商业和潜在应用:十年回顾
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-04-23 DOI: 10.1590/0104-1428.09420
L. D. Marestoni, H. Barud, R. Gomes, Rebeca Priscila Flora Catarino, N. Hata, J. Ressutte, W. Spinosa
{"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}
引用次数: 9
Mechanical and water absorption properties and morphology of melt processed Zein/PVAl blends 熔融处理的玉米蛋白/PVAl共混物的力学、吸水性能和形貌
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-04-23 DOI: 10.1590/0104-1428.10619
Sandro Junior Vessoni Torres, G. B. Medeiros, F. Rosário, F. Yamashita, L. Mattoso, E. Corradini
{"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}
引用次数: 2
Surface functionalization of polyvinyl chloride by plasma immersion techniques 等离子体浸没技术研究聚氯乙烯的表面功能化
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-04-23 DOI: 10.1590/0104-1428.06020
Péricles Lopes Sant’Ana, J. Bortoleto, N. Cruz, E. Rangel, Steven Frederick Durrant, W. Schreiner
{"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}
引用次数: 5
Silane-coupled kenaf fiber filled thermoplastic elastomer based on recycled high density polyethylene/natural rubber blends 基于再生高密度聚乙烯/天然橡胶共混物的硅烷偶联红麻纤维填充热塑性弹性体
IF 1.3 4区 化学
Polimeros-ciencia E Tecnologia Pub Date : 2021-01-01 DOI: 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}
引用次数: 1
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