Pub Date : 2022-01-01DOI: 10.1590/0104-1428.20210116
M. A. Goes, J. P. Santos, B. Carvalho
The use of controlled extension flows associated with processing with predominant shear flows can bring gains in the dispersive capacity of nanofillers during the processing of nanocomposites. In this work, we use a controlled flow device coupled to the matrix of a single-screw extruder to process PP matrix composites containing 0.5% and 2.5% (v/v) of MWCNT. The nanocomposites were evaluated by optical microscopy and oscillatory rheological analysis. The clusters size analysis showed that in PP/0.5MWCNT-el, 70.5% of all its clusters were below 1µm 2 while its analog processed without the extensional flow showed 59.8% of its clusters below this value. The rheological analysis allowed to verify that the compositions processed with the presence of the extensional flow have their crossover frequencies shifted to lower values, that is, longer relaxation times corroborating that improved degrees of dispersion were achieved.
在纳米复合材料的加工过程中，利用以剪切流为主的可控扩展流可以提高纳米填料的分散能力。在这项工作中，我们使用一个与单螺杆挤出机的基体耦合的控制流量装置来加工含有0.5%和2.5% (v/v) MWCNT的PP基复合材料。通过光学显微镜和振荡流变学分析对纳米复合材料进行了表征。聚簇大小分析表明，在PP/0.5MWCNT-el中，70.5%的聚簇小于1 μ m 2，而未经拉伸流处理的模拟物中，59.8%的聚簇小于该值。流变分析可以验证，在拉伸流存在的情况下处理的组分，其交叉频率转移到较低的值，即更长的松弛时间，证实了分散度的改善。
{"title":"Improving the dispersion of multiwalled carbon nanotube in polypropylene using controlled extensional flow","authors":"M. A. Goes, J. P. Santos, B. Carvalho","doi":"10.1590/0104-1428.20210116","DOIUrl":"https://doi.org/10.1590/0104-1428.20210116","url":null,"abstract":"The use of controlled extension flows associated with processing with predominant shear flows can bring gains in the dispersive capacity of nanofillers during the processing of nanocomposites. In this work, we use a controlled flow device coupled to the matrix of a single-screw extruder to process PP matrix composites containing 0.5% and 2.5% (v/v) of MWCNT. The nanocomposites were evaluated by optical microscopy and oscillatory rheological analysis. The clusters size analysis showed that in PP/0.5MWCNT-el, 70.5% of all its clusters were below 1µm 2 while its analog processed without the extensional flow showed 59.8% of its clusters below this value. The rheological analysis allowed to verify that the compositions processed with the presence of the extensional flow have their crossover frequencies shifted to lower values, that is, longer relaxation times corroborating that improved degrees of dispersion were achieved.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67121522","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 : 2022-01-01DOI: 10.1590/0104-1428.20220077
G. A. Carpenedo, N. B. Guerra, M. Giovanela, M. Paoli, J. S. Crespo
{"title":"Evaluation of lignin as stabilizer in vulcanized natural rubber formulations","authors":"G. A. Carpenedo, N. B. Guerra, M. Giovanela, M. Paoli, J. S. Crespo","doi":"10.1590/0104-1428.20220077","DOIUrl":"https://doi.org/10.1590/0104-1428.20220077","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67122141","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 : 2022-01-01DOI: 10.1590/0104-1428.20220042
M. Kondo, L. Montagna, G. F. Morgado, André Luiz Guimarães de Castilho, Larissa Anne Pereira dos Santos Batista, E. C. Botelho, M. L. Costa, F. R. Passador, M. C. Rezende, Marcos Valério Ribeiro
{"title":"Recent advances in the use of Polyamide-based materials for the automotive industry","authors":"M. Kondo, L. Montagna, G. F. Morgado, André Luiz Guimarães de Castilho, Larissa Anne Pereira dos Santos Batista, E. C. Botelho, M. L. Costa, F. R. Passador, M. C. Rezende, Marcos Valério Ribeiro","doi":"10.1590/0104-1428.20220042","DOIUrl":"https://doi.org/10.1590/0104-1428.20220042","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67122094","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 : 2022-01-01DOI: 10.1590/0104-1428.20220029
Alan Kardec da Silva, E. C. C. Torquato, Jacira Aparecida Castanharo, M. A. S. Costa, M. Marques, L. C. Costa
{"title":"Evaluation of magnetic poly(methyl methacrylate) microspheres as catalysts in heterogeneous Fenton processes","authors":"Alan Kardec da Silva, E. C. C. Torquato, Jacira Aparecida Castanharo, M. A. S. Costa, M. Marques, L. C. Costa","doi":"10.1590/0104-1428.20220029","DOIUrl":"https://doi.org/10.1590/0104-1428.20220029","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67121504","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 : 2022-01-01DOI: 10.1590/0104-1428.20220031
G. N. Campos, A. R. Coimbra, A. A. Silva, E. V. D. Rocha, F. N. Linhares, C. Furtado, A. M. F. Sousa
{"title":"Cross-link density measurement of nitrile rubber vulcanizates using dynamic shear test","authors":"G. N. Campos, A. R. Coimbra, A. A. Silva, E. V. D. Rocha, F. N. Linhares, C. Furtado, A. M. F. Sousa","doi":"10.1590/0104-1428.20220031","DOIUrl":"https://doi.org/10.1590/0104-1428.20220031","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67121535","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 : 2022-01-01DOI: 10.1590/0104-1428.20210066
A. Leite, Hamille Viotto, T. Nunes, D. Pasquini, A. Pero
{"title":"Cellulose nanocrystals into Poly(ethyl methacrylate) used for dental application","authors":"A. Leite, Hamille Viotto, T. Nunes, D. Pasquini, A. Pero","doi":"10.1590/0104-1428.20210066","DOIUrl":"https://doi.org/10.1590/0104-1428.20210066","url":null,"abstract":"","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67121347","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}
Juliana Cristina Kreutz, P. R. Souza, Viviane Prima Benetti, A. Freitas, P. Bittencourt, L. Gaffo
Abstract Virgin polystyrene (PS) composites were reinforced with medium density fiberboard (MDF) residue, considering the influence of fiber content. The composites were evaluated for their morphology, identification of functional groups and thermal behavior. Mechanical tests and a degradation study under ultraviolet radiation (UV) were also performed. The results showed that the best properties were obtained for composites with 4% by mass of MDF waste. The addition of residue was found to increase thermal stability of polystyrene compared to its pure form. The morphology of the composites showed homogeneity of the material. In the degradation tests under ultraviolet (UV) radiation, it was found that the presence of MDF residue slows down the matrix degradation process when evaluated by means of tensile strength. Polystyrene composites reinforced with MDF residues showed good mechanical properties and can be applied in the development of materials that do not need a good appearance.
{"title":"Mechanical and thermal properties of polystyrene and medium density fiberboard composites","authors":"Juliana Cristina Kreutz, P. R. Souza, Viviane Prima Benetti, A. Freitas, P. Bittencourt, L. Gaffo","doi":"10.1590/0104-1428.07120","DOIUrl":"https://doi.org/10.1590/0104-1428.07120","url":null,"abstract":"Abstract Virgin polystyrene (PS) composites were reinforced with medium density fiberboard (MDF) residue, considering the influence of fiber content. The composites were evaluated for their morphology, identification of functional groups and thermal behavior. Mechanical tests and a degradation study under ultraviolet radiation (UV) were also performed. The results showed that the best properties were obtained for composites with 4% by mass of MDF waste. The addition of residue was found to increase thermal stability of polystyrene compared to its pure form. The morphology of the composites showed homogeneity of the material. In the degradation tests under ultraviolet (UV) radiation, it was found that the presence of MDF residue slows down the matrix degradation process when evaluated by means of tensile strength. Polystyrene composites reinforced with MDF residues showed good mechanical properties and can be applied in the development of materials that do not need a good appearance.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45895779","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. D. C. D. Almeida, João Paulo Teixeira da Silva, Felipe Fernando da Costa Tavares, Ludmila Leite Araujo, Jefferson de Souza Zeferino, R. Santana
Abstract In this work, a bio-based adhesive is prepared from Protium heptaphyllum resin. The resin is first characterized by 1H and 13C nuclear magnetic resonance spectroscopy and the bioadhesive is then prepared using a simple mixture of the resin with linseed oil, catalyzed by cobalt octanoate, to induce crosslinking. The precursors and bioadhesive obtained are characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The NMR analysis shows the presence of groups of triterpenes, such as α- and β-amyrins, and diols, such as brein and maniladiol. Thermogravimetric analysis reveals that the resin has less thermal stability than the bioadhesive. Mechanical tests indicate that the bioadhesive has greater adhesion strength compared to the commercial adhesive, reaching an average stress at break of 7.66 and 0.113 MPa for the wood and carbon steel substrates, respectively. In conclusion, the bioadhesive can be used for the production of composites.
{"title":"Development of a bio-based adhesive from Protium heptaphyllum resin","authors":"M. D. C. D. Almeida, João Paulo Teixeira da Silva, Felipe Fernando da Costa Tavares, Ludmila Leite Araujo, Jefferson de Souza Zeferino, R. Santana","doi":"10.1590/0104-1428.10020","DOIUrl":"https://doi.org/10.1590/0104-1428.10020","url":null,"abstract":"Abstract In this work, a bio-based adhesive is prepared from Protium heptaphyllum resin. The resin is first characterized by 1H and 13C nuclear magnetic resonance spectroscopy and the bioadhesive is then prepared using a simple mixture of the resin with linseed oil, catalyzed by cobalt octanoate, to induce crosslinking. The precursors and bioadhesive obtained are characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The NMR analysis shows the presence of groups of triterpenes, such as α- and β-amyrins, and diols, such as brein and maniladiol. Thermogravimetric analysis reveals that the resin has less thermal stability than the bioadhesive. Mechanical tests indicate that the bioadhesive has greater adhesion strength compared to the commercial adhesive, reaching an average stress at break of 7.66 and 0.113 MPa for the wood and carbon steel substrates, respectively. In conclusion, the bioadhesive can be used for the production of composites.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46001804","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 This study aimed to evaluate the process of cellulose extraction from yacon stem using combined pulping and bleaching processes to produce nanofibrillated cellulose (NFC). First, a chemical pulping process with NaOH was applied and, subsequently, the pulp obtained was bleached. From the chemical pulp (CP) bleached, NFC was obtained by the mechanical defibrillation in a colloidal grinder. Then, chemical composition, and infrared analysis of the pulps were performed. The pulping process showed a lower amount of extractives and lignin content, as a low yield and an excessively dark pulp. The CP bleached with NaClO2 showed the best results increased whiteness of the pulp. A suspension of NFC with fibers of 5-60 nm in diameter, high crystallinity index, and thermal stability was obtained. The results are promising and demonstrate the technical feasibility of obtaining NFC from yacon stems waste which is ideal to apply to other materials of the industry.
{"title":"Extraction and characterization of nanofibrillated cellulose from yacon plant (Smallanthus sonchifolius) stems","authors":"R. S. D. Sousa, A. S. D. Andrade, M. L. Masson","doi":"10.1590/0104-1428.09620","DOIUrl":"https://doi.org/10.1590/0104-1428.09620","url":null,"abstract":"Abstract This study aimed to evaluate the process of cellulose extraction from yacon stem using combined pulping and bleaching processes to produce nanofibrillated cellulose (NFC). First, a chemical pulping process with NaOH was applied and, subsequently, the pulp obtained was bleached. From the chemical pulp (CP) bleached, NFC was obtained by the mechanical defibrillation in a colloidal grinder. Then, chemical composition, and infrared analysis of the pulps were performed. The pulping process showed a lower amount of extractives and lignin content, as a low yield and an excessively dark pulp. The CP bleached with NaClO2 showed the best results increased whiteness of the pulp. A suspension of NFC with fibers of 5-60 nm in diameter, high crystallinity index, and thermal stability was obtained. The results are promising and demonstrate the technical feasibility of obtaining NFC from yacon stems waste which is ideal to apply to other materials of the industry.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41446477","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 Flexible transparent substrate materials, which was able to withstand high dynamic strain, in contrast to traditional substrate materials. A flexible and transparent material with advantages including transparency, stable size, and excellent corrosion and electrical resistance was provided. The polyimide(PI) film was prepared by introducing a structure with a high content of F atom and a fine optimization process to enhance the various properties of the film. However, the properties of the films were optimized effectively by gradient vacuum and secondary dissolution so that the film had a transmittance at 400 nm of 82%. The films with low dielectric constant and low dielectric loss represent the breakdown strength of 202 kV/mm. The glass transition temperature of the film was 267 °C, and the thermal expansion coefficient was 35ppm/k (30 °C~270 °C), indicated outstanding thermal dimensional stability. Therefore, this polyimide film was an optoelectronic device with extremely high application potential on the folding mobile phone and the PI film is the finest materials of screen.
{"title":"A foldable high transparent fluorinated polyimide (HFBAPP/6FDA) film material for transparent flexible substrate","authors":"Chuanhao Cao, Lizhu Liu, Xiaorui Zhang","doi":"10.1590/0104-1428.10520","DOIUrl":"https://doi.org/10.1590/0104-1428.10520","url":null,"abstract":"Abstract Flexible transparent substrate materials, which was able to withstand high dynamic strain, in contrast to traditional substrate materials. A flexible and transparent material with advantages including transparency, stable size, and excellent corrosion and electrical resistance was provided. The polyimide(PI) film was prepared by introducing a structure with a high content of F atom and a fine optimization process to enhance the various properties of the film. However, the properties of the films were optimized effectively by gradient vacuum and secondary dissolution so that the film had a transmittance at 400 nm of 82%. The films with low dielectric constant and low dielectric loss represent the breakdown strength of 202 kV/mm. The glass transition temperature of the film was 267 °C, and the thermal expansion coefficient was 35ppm/k (30 °C~270 °C), indicated outstanding thermal dimensional stability. Therefore, this polyimide film was an optoelectronic device with extremely high application potential on the folding mobile phone and the PI film is the finest materials of screen.","PeriodicalId":20282,"journal":{"name":"Polimeros-ciencia E Tecnologia","volume":"121 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73217585","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：