Unique compatibilized thermoplastic elastomer from polypropylene and epichlorohydrin rubber

Abstract

Thermoplastic elastomer (TPE) based on polypropylene (PP) and epichlorohydrin rubber (ECH) was prepared in the presence of maleic anhydride grafted polypropylene (MA-g-PP) as compatibilizer. The PP/ECH blends in the absence of compatibilizer showed very poor mechanical properties, especially low elongation at break values and higher tension set values. This was attributed to the poor compatibility between PP and ECH. On the other hand, in the case of compatibilized PP/ECH blends, MA-g-PP acted as a strong interfacial agent between PP and ECH phases and led to outstanding improvement in the mechanical and rheological properties. Compatibilized PP/ECH blends showed higher mixing torque values in comparison to the incompatible PP/ECH blends due to existence of better interaction between PP and ECH in the presence of MA-g-PP. Fourier transform infrared spectroscopy (FTIR) study clearly depicted the existence of strong chemical interactions between PP and ECH in the presence of MA-g-PP. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) studies suggested that the addition of MA-g-PP to PP/ECH blends increased the percentage crystallinity, which in turn enhanced the overall properties. Morphological studies clearly showed the prominent reduction in the domain size of dispersed ECH phase in the continuous PP matrix due to the incorporation of MA-g-PP as compatibilizer.