Silica‐filled polypropylene composites: The effect of ethylene diamine dilaurate and maleic anhydride grafted polypropylene on mechanical properties, water absorption, morphology, and thermal properties

The effect of two compatibilizers, i.e. ethylene diamine dilaurate (EDD) and maleic anhydride grafted polypropylene (MAPP) on the mechanical properties, water absorption, morphology, and thermal properties of silica‐filled polypropylene (PP/Sil) composites were studied. The results show that the tensile, impact and flexural strengths (up to 2 php), Young's modulus, and elongation at break (Eb) increased with increasing EDD content. However, increasing MAPP content increases the tensile strength, Young's modulus, impact and flexural strengths, and water absorption resistance. At a similar compatibilizer content, EDD exhibits higher Eb, impact and flexural strengths but lowers tensile strength, Young's modulus, and water absorption resistance compared with MAPP. Scanning electron microscopy study of tensile fractured surfaces exhibits the evidence of better silica‐PP adhesion with MAPP and EDD compared with the similar composites but without compatibilizer. Fourier transform infra red spectra provide an evidence of interaction between EDD or MAPP with PP/Sil composites. Termogravimetry analysis results indicate that the addition of EDD or MAPP slightly increases the thermal stability of PP/Sil composites. Differential scanning calorimetry also indicates that PP/Sil composites with EDD or MAPP have higher heat fusion (ΔHf(com)) and crystallinity (Xcom) than similar composites but without compatibilizer. POLYM. COMPOS., 2008.