In situ Polypropylene Nanocomposites: Gas‐Phase Polymerization of Propylene in the Presence of Nanofillers using Nanosilica‐Supported‐Zirconocene Catalyst

Abstract

This work concentrates on using the gas‐phase polymerization technique for the production of highly loaded nanocomposites. Filler loading levels near the vicinity of 40 wt% have been obtained using different nanofillers. Three different in situ Polypropylene (PP) nanocomposites, i.e., Cloisite‐20A filled polypropylene (CFPP), Kaolin filled polypropylene (KFPP) and nanosilica filled polypropylene (SFPP) have been prepared by gas‐phase polymerization. The catalyst used is Nanosilica‐Supported‐Zirconocene. The fillers used are Closite‐20A, Kaolin and nanosilica, respectively. These were pre‐treated with MAO (Methylaluminoxane) to inhibit their deactivating action on the catalyst because of the presence of either acidic or basic groups on their surfaces; in this way MAO acts as a co‐catalyst for the three polymerization reactions being discussed. Significantly higher molecular weight polypropylene was formed with nanosilica as the filler. The melting temperature and enthalpy is also observed to be comparatively higher in this case. However, in the case of other fillers, the molecular weights, as well as melting points, are comparatively lower. With the catalyst used, a mixture of crystalline and amorphous polypropylene was observed to form. Comparatively lesser amounts of crystalline polypropylene are also observed.