Compatibilization of polyoxymethylene (POM)/polypropylene (PP) blends and investigation of mechanical, rheological and solid-state creep properties

Abstract

In the present study, polyoxymethylene (POM)/polypropylene (PP) blends with different compositions were prepared by extrusion method, and morphological, rheological, mechanical and creep behaviors were characterized. In addition, blend samples with different compatibilizer (maleic anhydride grafted polypropylene, PPgMA) content were prepared and the optimum compatibilizer concentration was determined. In the morphological analyses, some gaps were observed at the interfaces of PP and POM phases, which indicate weak interaction between the polymer phases. In addition, it was observed that the co-continuous phase morphology could be provided for the blend sample containing equal PP and POM concentration. Finally, it was found that phase separations could be reduced and good adhesion between phases could be achieved by incorporation of PPgMA into to the blend samples. Rheological analysis of the samples revealed that POM has lower melt viscosity than PP, and the viscosity of the blend samples increases with increasing PP content. Evaluation of mechanical, rheological and creep test results indicate that incorporation of PPgMA into the blend structure has improved the elastic modulus and creep resistance parameters due to providing better adhesion between the phases. Mechanical and creep analyses also showed that improvements in elastic modulus and creep resistance are the highest in the case of the compatibilizer concentration was 10-15 phr, and it was also observed that the improvements in these parameters started to disappear in case of compatibilizer concentration is 20 phr. From these results, it was concluded that optimum compatibilization can be providing with the use of PPgMA at the concentration of 10-15 phr.