Crosslinker free thermally induced crosslinking of hydrogenated nitrile butadiene rubber. Issue 16 (24th August 2018)

• Record Type: Journal Article
• Authors: Verdier, Nina; Lepage, David; Prébé, Arnaud; Aymé‐Perrot, David; Dollé, Mickaël; Rochefort, Dominic
• Is Part Of: Journal of polymer science. Volume 56:Issue 16(2018)
• Page Start: 1825
• Page End: 1833
• Publication Date: 2018-08-24
• Subjects: crosslinking -- heat treatment -- hydrogenated nitrile butadiene rubber -- reinforcement -- tensile test; 547
• DOI: 10.1002/pola.29063
• Languages: English
• ISSNs: 0887-624X

Abstract

ABSTRACT: Hydrogenated nitrile butadiene rubbers (HNBRs) are hydrogenated copolymers of acrylonitrile and butadiene, which are often used in composites or polymer blends. These copolymers are usually cured with peroxides or vulcanized with sulfur to reinforce their mechanical resistance and improve their chemical stability. However, using such crosslinking reagents can be problematic for high value systems where residual H2 O2 or S can be detrimental for the application. To address this limitation, we studied the thermally induced crosslinking of HNBR at high temperature (240 °C) with oxygen. To understand the impact of conditions (temperature, time, and atmosphere) on the chemical structure and the mechanical properties of HNBR, different thermal treatments were investigated. We show that HNBR forms a ladder structure during treatment in the presence of O2 which result in a reinforcement of the elastomer. Tensile tests and DSC show both alkene and nitrile moieties are involved in the reaction, leading to a mechanical resistance comparable with a HNBR crosslinked with peroxides or sulfur. These findings will help achieving a better control on the crosslinking to provide HNBRs with desired properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2018, 56, 1825–1833 Abstract : A new method of crosslinking hydrogenated nitrile butadiene rubber (HNBR) is achieved through thermal treatment and without any additives. Temperature, time, and atmosphere are studied to determine the effect of the treatment on the polymer. Heating the polymer at 240 °C for at least 90 min under air results in a crosslinking density similar to what is obtained with chemical reagents. The approach is particularly efficient on HNBR with very low butadiene content, where the conventional techniques fail.