Influence of Acrylate Content on the Properties of Ethylene Methyl Acrylate -Multi Walled Carbon Nanotube Composites

In this study, nanocomposites based on multi walled carbon nanotube (MWNT) with three commercial grades of ethylene methyl acrylate copolymers (EMA) with 9, 24 and 30 wt% methyl acrylate (MA) contents, respectively have been prepared by solution mixing followed by melt blending technique. The state of dispersion of the MWNTs found to be inferior with increasing MA content in the EMA matrix as observed by HRTEM. Higher state of dispersion of MWNTs in EMA matrix lead to decreased crystallinity, increased crystallite size and increased crystallization temperature. The storage moduli of the composites drop very sharply with increasing% strain for EMA with 30% MA content and it reflects the typical Payne effect. The storage modulus of the composite is significantly increased by the incorporation of MWNTs particularly at higher temperatures. A unique crossover of tans versus frequency plots of composites with that of the pristine polymers is noticed for EMA with 24 and 30% MA contents based composites, respectively, where the degree of aggregation are higher. The frequency corresponding to the crossover depends on the degree and length scale of aggregation. The MWNTs provide better thermal stability especially for the composites based on EMA with 9% MA, where the highest state of dispersion is observed by morphological analysis. Thus, in EMA with 9% MA, pristine MWNTs can be homogeneously dispersed by solution mixing followed by melt processing technique.