Polímeros: Ciência e Tecnologia
https://revistapolimeros.org.br/article/doi/10.1590/0104-1428.20220031
Polímeros: Ciência e Tecnologia
Original Article

Cross-link density measurement of nitrile rubber vulcanizates using dynamic shear testa

Gustavo Ninho Campos; Ana Carolina Ribeiro Coimbra; Arianne Aparecida da Silva; Elisson Brum Dutra da Rocha; Felipe Nunes Linhares; Cristina Russi Guimarães Furtado; Ana Maria Furtado de Sousa

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Abstract

Cross-link density impacts most mechanical properties of rubber, therefore it is necessary to have a method to measure it. The most widely used method is via equilibrium swelling, however, it is time consuming and uses organic solvents. Dynamic Shear Test (DST) can be used to calculate both chemical and physical cross-links in rubber compounds in shorter times than by swelling equilibrium method, and without the use of solvents. In this work, equilibrium swelling using toluene and acetone was used to validate the dynamic shear tests for different nitrile rubber (NBR) compounds. The DST had a good correlation with the swelling equilibrium method using acetone, with a correlation coefficient of ~0,91, validating the use of DST. Moreover, the use of the Modified Guth-Gold equation (instead of Guth-Gold Equation with Medalia correction) also allowed to deduct the effect of carbon black on the cross-link density from the DST.

 

 

Keywords

nitrile rubber, cross-link density, dynamic shear test, swelling equilibrium, solubility parameter

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