Borracha natural e nanocompósitos com argila

Rippel, Márcia Maria; Bragança, Fábio do Carmo

doi:10.1590/s0100-40422009000300024

Cited by 20 publications

(18 citation statements)

References 21 publications

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“…Natural rubber (NR) is a bioderived elastomeric polymer which is extensively used for the production of tires, gloves and gaskets (Rippel and Braganç a, 2009;Kohjiya and Ikeda, 2014). It is harvested from the Hevea Brasiliensis tree as a liquid suspension called latex in which the presence of other substances such as proteins, fatty acids, carbohydrates to name a few, make its properties highly variable.…”

Section: Introductionmentioning

confidence: 99%

Influence of the irradiation dose in the cellular structure of natural rubber foams cross-linked by electron beam irradiation

Salmazo

Lopez‐Gil

Ariff

et al. 2016

Industrial Crops and Products

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a b s t r a c tThis work focused on the production of natural rubber foams by cross-linking the polymer matrix using high energy electron beam at different irradiation doses (from 50 to 150 kGy) and foaming it with a chemical blowing agent. The aim was to study how the irradiation dose influenced the cellular structure morphology of the produced foams. This was accomplished by quantifying the evolution of cellular structure parameters, such as cell size and cell density, with respect to foaming time and irradiation dose. The results showed that the foams irradiated at the lowest dose are more prone to suffer cellular structure degeneration, resulting in the formation of bimodal cellular structures, while foams irradiated with the highest dose, exhibited more uniform cellular structure. In the latter case, the nucleation density clearly increased resulting in the formation of foams with homogeneous cellular structures and smaller cell sizes (≈20 m).

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Section: Introductionmentioning

confidence: 99%

Influence of the irradiation dose in the cellular structure of natural rubber foams cross-linked by electron beam irradiation

Salmazo

Lopez‐Gil

Ariff

et al. 2016

Industrial Crops and Products

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“…A borracha natural é um hidrocarboneto cuja fórmu-la química é um polímero de poli(cis-1,4-isopreno) (Rippel & Bragança, 2009). Este hidrocarboneto está presente em mais de 7.500 espécies vegetais, dentre as quais a Hevea brasiliensis (Willd.…”

Section: Introductionunclassified

“…Diferentemente de outros polímeros, a borracha natural apresenta certas características físico-químicas úni-cas, sendo, portanto uma matéria-prima insubstituível para mais de 50 mil produtos industrializados, como pneus, adesivos, couro vegetal, materiais cirúrgicos e uma diversa gama de outros produtos (Rippel & Bragança, 2009).…”

Section: Introductionunclassified

Avaliação de clones de seringueira para a região noroeste do Estado de São Paulo

et al. 2015

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As correlações genéticas e fenotípicas foram significativas e positivas entre todos os anos de produção. Para o vigor, a significância dos coeficientes de correlação genotípica e fenotípica diferiram na pré-sangria e na pós-sangria. Pelos valores de produção de borracha observados, os clones IRCA 111 e PB 235 são considerados favorá-veis à recomendação em pequena escala para a região de Votuporanga. Com base nos resultados obtidos, é possível realizar uma seleção precoce para o caráter de produtividade, usando-se os dados obtidos no primeiro ano de avaliação. Por causa das diferenças observadas entre os períodos de pré-sangria e pós-sangria, não é aconselhável realizar uma seleção precoce no período de pré-sangria, visando ao caráter de vigor. Palavras-chave: Evaluation of rubber-tree clones for the northwest region of São Paulo StateClones of rubber-tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell. Arg.] have achieved the highest yields of rubber in the State of São Paulo, Brazil. The objective of this study was to evaluate the yield and vigor of 14 rubber-tree clones cultivated in the region of Votuporanga and determine changes in the trend of annual correlation to examine the possibility of an early selection based on the studied characters. The yield of rubber was evaluated in the ½S d/4 5d/7 11m/y ET 2,5% tapping system, for a period of eight years. Vigor was also examined by measuring the girth for 16 years. The clones IRCA 111 and PB 235 showed the best yield performance. The best results of vigor, was achieves by clones IAC 15 and IAC 44. Genetic and phenotypic correlations were significant and positive for all production years. The significance of the genotypic and phenotypic correlation coefficients of vigor differed in the pre and post-tapping periods. Considering the rubber production found, the clones IRCA 111 and PB 235 can

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“…Natural rubber is used in a bunch of industrial applications and manufactured products, like tires and gloves, but its presumable biological properties are not explored as it should be. 6 Latex and its constituents have been specifically implicated in multiple biological propertiesand it is known to stimulate angiogenic activity, cell adhesion, extracellular matrix formation, and to improve wound healing in skin tissue. 7,8 Ferreira et al (2009), 9 showed that the non-rubber constituents of H. brasiliensis latex are the bioactive fraction responsible for angiogenic properties of this material.Latexconstituents can be separated in three parts when centrifuged at high speed, consisting of the rubber cream, centrifuged serum (C-serum) and the bottom fraction (B-serum).…”

Section: Introductionmentioning

confidence: 99%

Free-radical Scavenging properties and Cytotoxic Activity Evaluation of Latex C-serum from Hevea brasiliensis RRIM 600

Kerche

Cavalcante

Danna

et al. 2016

FRA

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Background: There are few studies exploring the antioxidant properties of the latex C-serum of the Hevea brasiliensis latex and their possible use for therapeutic application. Objective: This study investigated the in vitro antioxidant activity of the latex C-serum of H. brasiliensis and assessed the cytotoxicity of this fraction in two human cell lines derived from normal tissue (MRC-5 and CCD 1059sk. Chemical characterization was also assessed. Methods: Latex from H. brasiliensis was centrifuged and the C-serum phase was tested for in vitro free radical scavenging assays, such as hydroxyl and nitric oxide radicals, hydrogen peroxide and total antioxidant capacity by the phosphomolibdate method. Latex C-serum was also investigated for cytotoxic properties by the MTT test. Latex C-serum was chemical characterized by Infrared Spectroscopy Fourier Transform (FTIR). Results: Latex C-serum effectively scavenged hydroxyl and nitric oxide radicals and hydrogen peroxide and presented potent antioxidant activity. The results were compared to ascorbic acid, a standard antioxidant. The cytotoxicity evaluation of latex C-serum demonstrated cell line dependency and for CCD 1059sk cells derived from skin fibroblasts, latex C-serum was not cytotoxic. FTIR showed the presence of proteins in latex C-serum. Conclusion: Latex C-serum from Hevea brasiliensis presented strong antioxidant potential and these results openthe possibility of further studies aiming the use of latex C-serum as treatment for skin diseases related to reactive oxygenspecies or skin preventive pharmacological formulations.

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Borracha natural e nanocompósitos com argila

Cited by 20 publications

References 21 publications

Influence of the irradiation dose in the cellular structure of natural rubber foams cross-linked by electron beam irradiation

Influence of the irradiation dose in the cellular structure of natural rubber foams cross-linked by electron beam irradiation

Avaliação de clones de seringueira para a região noroeste do Estado de São Paulo

Free-radical Scavenging properties and Cytotoxic Activity Evaluation of Latex C-serum from Hevea brasiliensis RRIM 600

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