Properties and effect of preparation method of thermally conductive polypropylene/aluminum oxide composite

Polypropylene/aluminum oxide composite was fabricated by using two different processing methods: mechanical grinding (MG) and melt mixing (MM). Unlike traditional MM, MG after hot pressing can form a segregated structure. The method is based on sintering of a polymer composite with core–shell-like structure. Scanning electron microscopy was performed to observe the segregated structure and filler distribution. Filler was localized at the interface of the polymer matrix, resulting in the segregated structure. This localization indicates that such segregated structure can help improve the thermal conductivity of the composite. The composite prepared by MM did not possess continuous thermally conductive paths of filler because of shear mixing. Differential scanning calorimetry, thermogravimetric analysis, and rheological measurements were carried out to examine the thermal and mechanical properties of the samples obtained by each fabrication method.