Rheological and Mechanical Properties of Silica/Nitrile Butadiene Rubber Vulcanizates with Eco-Friendly Ionic Liquid.

Munir Hussain,Yihu Song,Zhiyun Li,Wanjie Wang,Xinpeng Fan,Sohail Yasin,Muhammad Adnan Akram,Qiang Zheng,Hafeezullah Memon

doi:10.3390/polym12112763

Munir Hussain, Yihu Song + Show 7 more

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https://doi.org/10.3390/polym12112763

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Abstract

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

Highlights

Nitrile butadiene rubber (NBR) with exceptional oil resistance does not possess a self-reinforcing and strain-induced crystallization effect [1]
The results show enhancement in mechanical properties at both room temperature and high temperatures (60 ◦ C and 100 ◦ C), along with improved crosslinking density and silica dispersity
Once [EMIM]OAc is combined with Si69/1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) coupling agent (Si69), vc becomes higher than that using Si69 only

Summary

Introduction

Nitrile butadiene rubber (NBR) with exceptional oil resistance does not possess a self-reinforcing and strain-induced crystallization effect [1]. Nanoparticles such as carbon black or silica are extensively used to reinforce NBR vulcanizates [2]. Dynamic modulus reduces greatly with increasing strain amplitude beyond the linear viscoelastic region [13,14,15] The former is termed the reinforcement effect and the latter is referred to as the Payne effect [16,17,18], both being long-standing topics in the fields of rheology and rubber nanocomposites.

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