A parametric study of the terminal maleation of polypropylene through an Alder Ene reaction

Alder ene functionalization of polyisobutene oligomer and styrene-butadiene-styrene triblock copolymer

“…The polymer is characterized by a butadiene/styrene ratio of 69/31 by weight, an average molecular weight of blocks of 9300-41400-9300, a content of the vinyl units in the butadiene block of 10 wt % and a density of 0.94 g/cm 3 .…”

“…Indeed the Alder ene reaction of MAH with various olefins is second order overall [11] and maleation experiments performed onto end unsaturated polypropylene indicated that high temperature, but below 230 8C, and MAH concentration increase the grafting of SA units [3].…”

“…In the last years, the Alder ene reactive modification of vinylidene terminated polyolefins has been thoroughly investigated because of its suitability for polymer functionalization in the melt phase [1][2][3][4]. Particularly, polyisobutene (PIB) [5][6][7][8][9] and polybutadiene (PB) [10] have been efficiently functionalized in the melt with maleic anhydride (MAH).…”

“…Since the enophile is electron deficient, Lewis acid is effective in accelerating the Alder ene reaction. Thus, catalytic amount of stannous and ruthenium chlorides in the presence of an inhibiting radical-induced grafting agent, have been shown to be very efficient in the functionalization of olefin terminated polypropylene [3]. In connection with these findings, highly reactive low molecular weight PIBs with terminal double bonds prepared by BASF are very reactive in the Alder ene functionalization [13,14].…”

“…On the other hand, since the reaction requires high temperature and residence time special attention have to be addressed and the stable free radical (2,2,6,6-tetramethyl-1-piperidinyloxy, TEMPO) is used to prevent thermally promoted radical side reactions [2,3].…”