The effect of fillers loading on properties of MWCNT/HIPS reinforced nanocomposites

Abstract

A new high impact polystyrene/multiwall carbon nanotubes (HIPS/MWCNTs) nanocomposite has been successfully developed. The mechanical, rheological, thermal and water absorption performances have been improved. The experimental design included one way MANOVA test to validate the significance of changes in HIPS due to 0.1wt%, 0.5wt%, 1wt%, 2.5wt%, 5wt%, 7.5wt% and 10wt% loadings of MWCNTs. An independent analysis for the different HIPS/MWCNTs nanocomposite was carried out. The improvement in Young's modulus ranged between 1.79% and 31.78% which confirmed that the load has been transferred successfully from the HIPS to the MWCNTs. There was an initial improvement of 4.24% in the impact strength at 0.1wt% of MWCNTs loading level, beyond which the value of the impact strength falls down. Thus an inverse relationship between the MWCNTs loading level and the impact strength was identified. The viscosity was found to be directly proportional to MWCNTs' loading, as it went up to five times the value of pure HIPS at loading level of 7.5wt% of MWCNTs. The water absorption resistance was found to be directly related to MWCNTs loading with improvement between 24% and 72.5% following the increase in MWCNTs loading. The MWCNTs loading also demonstrated an effect on the glass transition temperature with values ranging from 0.8% decrease and 1.4% increase. The HIPS/MWCNTs nanocomposite with 0.1 wt% of MWCNTs loading had yielded the best results in terms of Young's modulus, izod impact energy, viscosity, Tg, and water absorption. Further loading MWCNTs found to result in lower performance in one or more properties of the HIPS/MWCNTs nanocomposite. The cost of producing the new product at the optimum loading of 0.1wt% of MWCNTs was found to be 25% higher compared to the price of HIPS