Pre-dispersing Process of Montmorillonite by Water and Toluene: Influence on Thermal Properties of Ethylene Vinyl Acetate / Montmorillonite Nanocomposites

Azlin Fazlina Osman,Tuty Fareyhynn Mohammed Fitri,Md Rakibuddin,Yusrina Mat Daud,Supri A Ghani,H.A Abdulbari

doi:10.1051/matecconf/201711102007

Abstract

Organanically modified montmorillonite (organo-MMT) was incorporated into ethylene vinyl acetate (EVA) copolymer to improve its thermal stability. A processing procedure, the so called ‘predispersing’ process of the organo-MMT was introduced prior to melt compounding process of both constituents in order to facilitate the nanofiller dispersion in the EVA matrix. Water and toluene were used as pre-dispersing medium, while magnetic stirring and ultrasonication were utilized as pre-dispersing method. The effects of pre-dispersing medium and method on thermal behaviour of neat EVA and EVA nanocomposites were analysed. It was anticipated that improvement in organo-MMT dispersion would enhance the matrix-nanofiller interactions, thereby the thermal properties of the resultant EVA/MMT nanocomposite. Based on thermal studies by thermogravimetric analysis (TGA), the organo-MMT nanofiller pre-dispersed by ultrasonication in water medium for 2 minutes (MMT(W)2m – u) resulted in most significant thermal stabilizing effect to the EVA copolymer. This was due to the significant improvement in the organo-MMT dispersion when the above mentioned pre-dispersing parameters were employed. Apparently, the result indicates that the high temperature behaviour of the nanocomposite can be affected by the strength of interphase interactions between the matrix and nanofiller which is also influenced by the dispersion of the organo-MMT.

Highlights

Ethylene vinyl acetate (EVA) copolymer is a polymeric material that exhibits softness and flexibility similar to elastomeric materials, yet it can be processed like other thermoplastic [1]
Based on thermal studies by thermogravimetric analysis (TGA), the organo-MMT nanofiller pre-dispersed by ultrasonication in water medium for 2 minutes (MMT(W)2m_u) resulted in most significant thermal stabilizing effect to the ethylene vinyl acetate (EVA) copolymer
The organo-MMT powder was pre-dispersed in two types of liquid medium which were distilled water and toluene in order to allow swelling of nanoplatelets prior to melt compounding with the EVA matrix, The organoclay was prepared as 20% solution in toluene and distilled water respectively and the suspension was stirred at room temperature by using two methods which were ultrasonication and magnetic stirring

Summary

Introduction

Ethylene vinyl acetate (EVA) copolymer is a polymeric material that exhibits softness and flexibility similar to elastomeric materials, yet it can be processed like other thermoplastic [1]. To be used as advanced material, further improvement in EVA thermal performance is needed, due to its tendency to thermally degrade under harsh environment and elevated temperatures. The enhancement in EVA thermal performance can be achieved by adding small amount of nanoclay as reinforcing filler [3, 4]. The resultant ‘EVA nanocomposite’ can perform greater thermal stability as compared to the neat EVA due to the dispersion of more thermally stable layered silicate material in the host copolymer structure. Dispersion of nanoclay filler must be optimized to effectively shield the polymer chains during thermal degradation process. Previous studies showed that poor dispersion of MMT clay inhibits significant thermal

Materials

Samples Preparation

Results and Discussion

Conclusion