Synthesis of polyethylene-graft-poly(styrene-co-maleic anhydride) and its compatibilizing effects on polyethylene/starch blends

Low density polyethylene (LDPE) was reacted with benzoyl peroxide (BPO) and 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) to prepare a latent macroinitiator, PE-TEMPO. Little polymer was synthesized when maleic anhydride (MAH) was bulk polymerized in the presence of the PE-TEMPO. However, addition of styrene accelerated the polymerization rate and PE-grafted-poly(styrene-co-maleic anhyride) [PE-g-P(ST-co-MAH)] was produced to a high yield. Chemical reaction between MAH units and hydroxyl groups of starch was nearly undetectable in the PE/PE-g-P(ST-co-MAH) /starch blend system, and the tensile properties of the blend were not enhanced significantly. However, addition of tetrabutyl titanate (TNBT) during the blending procedure improved the tensile properties significantly through an increased interfacial adhesion between the components in the blend system. (C) 2003 Wiley Periodicals, Inc.