Grafting of diethyl maleate and maleic anhydride onto styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS)

In this paper a study of the bulk functionalization of styrene-b-(ethylene- co-1-butene)-b-styrene triblock copolymer (SEBS) with diethyl maleate (DEM) or maleic anhydride (MAH) and dicumyl peroxide (DCP) as initiator in a Bra bender mixer is described. The determination of the functionalization degre e (ED) by NMR analysis indicates that the FD values depend on the feed comp osition and in particular on the DEM/DCP ratio. All obtained products were fractionated by solvent extraction and characterized by IR, NMR and GPC. Th e results obtained show that the functionalization takes place with a very large preference at the aliphatic carbons of the polyolefin block. Moreover occurrence of degradation and chain extension reactions gives st functiona lized product with a MWD larger than 1. Acetone extraction allows the isola tion of styrene rich oligomers, thus the high MW functionalized polymer has a lower content of aromatic units than original SEES. The results are described with reference to reaction mechanism previously r eported in case of the functionalization under similar conditions of polymo noalkenes. (C) 2000 EIsevier Science Ltd. All rights reserved.