ROLE OF REACTION-TIME IN BATCH PROCESS MODIFICATION OF ATACTIC POLYPROPYLENE BY MALEIC-ANHYDRIDE IN MELT

Following our studies on chemical modification proceses of polypropyle nes by maleic anhydride, some new experimental works are shown here th at check the possibilities of processing atactic polypropylene in the melt by a batch process. A modified polymer that is supposed to be use ful as an interfacial agent if used in heterogeneous systems based on polypropylene is also clearly obtained. The favorable effect of the no nstereoregularity of the polymer can be noted. This polymer has a high er level of modification than the stereoregular polymer (isotactic pol ypropylene), despite the lower processing temperature used that causes a decrease in the initiator activity. Otherwise, this article deals w ith the role played by the reaction time during the process. A mechani sm of chemisorption and some considerations about the fractal nature o f the reaction kinetics are proposed to explain the results obtained. (C) 1997 John Wiley & Sons, Inc.