Production and investigation of the thermal and mechanical properties of HIPS/EVACO blend composites with montmorillonite filling

In this project, it was aimed to produce new HIPS blend nanocomposites filled with organophilic montmorillonite (Org-MMT) and poly (ethylene-vinyl acetate-carbon monoxide) (EVACO) elastomeric compatibilizer and also investigate their thermal and mechanical properties. HIPS/EVACO blend (80/20 by weight) and 1,3,5 phr Org-MMT added ternary nanocomposites and HIPS/Org-MMT binary nanocomposite compounds were prepared by melt blending method in a laboratory type internal mixer and shaped using a hot press. The detailed morphological, thermal, static and dynamic mechanical properties of the prepared materials were examined in terms of filler loading degree and compatibilizing effect. It has been found that the composites produced have an intercalated nanocomposite structure according to their X-ray diffractograms. The produced blends and nanocomposites exhibited higher dynamic mechanical damping (tanδ) performances over a wide temperature range (-50 °C and +80 °C) compared to pure HIPS and HIPS/Org-MMT binary nanocomposites. The damping value of HIPS/EVACO blend increased by 54% at 25 °C compared to pure HIPS, while this value was found to be approximately 104% in ternary nanocomposites. The mechanical damping performances of binary nanocomposites without EVACO did not change compared to pure HIPS. In addition, the storage modulus values of the triple nanocomposites at this temperature increased compared to the HIPS/EVACO blend, indicating that the elastic character of the materials is high. This result was found to be consistent with higher creep recovery values with lower creep deformation and more heterogeneous fracture surface morphologies containing more and more small cracks in nanocomposites compared to blend. Impact strength values of HIPS/EVACO blend nanocomposites increased compared to blend, pure HIPS and binary composites. On the other hand, the toughness values of nanocomposites decreased compared to pure HIPS and blend, and this result was attributed to possible large cavities formed during tensile deformation at the interface of incompatible HIPS and EVACO polymers. It has been determined that ternary nanocomposites exhibit lower degradation rates at higher temperature, higher ash content show higher thermal stabilities compared to HIPS polymer. As a result, the nanocomposites containing 3 and 5 phr Org-MMT were found to have optimum stiffness/damping balance.