Polímeros: Ciência e Tecnologia
https://revistapolimeros.org.br/article/doi/10.1590/0104-1428.2051
Polímeros: Ciência e Tecnologia
Scientific & Technical Article

Influência do método de vulcanização nas propriedades mecânicas e na densidade de ligações cruzadas da borracha natural

The influence of vulcanization method on mechanical properties and crosslink density of natural rubber

Oliveira, Maria Aparecida de Souza; Cassu, Silvana Navarro; Mello, Sandra Aparecida Coelho de; Dutra, Jorge Carlos Narciso

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Resumo

A vulcanização é um importante fator que determina as propriedades mecânicas da borracha, mas a influência do método de vulcanização nas propriedades mecânicas do material, ainda é um assunto pouco explorado na literatura. Neste artigo, uma formulação à base de poli-cis-isopreno ou borracha natural (NR), denominada NR4010-A, foi vulcanizada em prensa e autoclave, com o objetivo de avaliar a influência do método de vulcanização na formação das ligações cruzadas e, consequentemente, nas propriedades mecânicas do material. Amostras do material vulcanizado, pelos dois métodos, foram caracterizadas por meio de análise reométrica, ensaio de inchamento e testes mecânicos, onde foi avaliada a resistência ao rasgo e à tração. Os resultados mostraram que para essa formulação, nas mesmas condições de temperatura, o método de vulcanização por autoclave se mostrou mais eficiente em relação às propriedades estudadas.

Palavras-chave

ligações cruzadas, NR, propriedades mecânicas, vulcanização.

Abstract

Vulcanization is an important factor on rubber mechanical properties determination. The influence of vulcanization method on mechanical properties is still an ongoing issue. Thus, a composition based in natural rubber (NR), named NR4010-A, was vulcanized by autoclave and press, on purpose to evaluated the vulcanization method influence on crosslink formation and thereafter on the mechanical properties of this material. Samples of vulcanized material in both conditions were characterized through swelling, rheometer tests, tear strength, strain strength and hardness. The mechanical properties studied and crosslink density were increased when the material was vulcanized by autoclave. Therefore, autoclave vulcanization method showed be more effective than press at the same conditions of temperature.

Keywords

crosslink, NR, mechanical properties, vulcanization.

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