Controlling Polypropylene Rheological Properties by Promoting Organic Peroxide during Extrusion with Improved Properties for Automotive Applications

Excellent stability and processability of Controlled-Rheology Polypropylene (CRPP) was mandatory parameters especially for automotive application. Selected organic peroxide which was used to control the rheology of PP should perform good stability in physical properties due to pre-process of compounding for automotive application. The common organic peroxide that widely used is 2,5-dimethyl-2,5-di-tert-butylperoxyhexane (DHBP). However, the problems that usually encountered are Melt Flow Index (MFI) stability, initial color, and the odor which come from decomposition process. Research and Development (RND) team of PT Chandra Asri Petrochemical, Tbk (CAP) did the study to change the type of organic peroxide to 3,6,9-triethyl-3,6,9,-tritnethyl-1,4,7-triperoxonane (TETMTPA) which was intended to improve these inferiorities when using DHBP. The results indicate better MFI stability, better initial color, and less odor when using TETMTPA than DHBP. This superiority is very applicable particularly for automotive application. Detailed analysis about volatile decomposition product from both peroxide indicated CRPP with TETMTPA has lower volatile compound which result lower odor level than CRPP with DHBP.