Graft copolymerization of oleic acid onto low-density polyethylene in the molten state

A graft copolymer of oleic acid (OA) onto low-density polyethylene (LDPE) was prepared using dicumyl peroxide (DCP) as an initiator in the molten state. The grafting was carried out in a Haake rheometer. The effects of the reaction time and the amount of DCP and the monomer on the percentage of grafting were studied. The rheological behavior and the melt-flow rate of the graft copolymer (LDPE-g-OA) were also investigated. FTIR spectroscopy and a mass spectrum were used to characterize the structure of LDPE-g-OA. The experimental results showed that when the OA amount was 10 wt % and the DCP amount was 0.4 wt % based on the LDPE the percentage of grafting of LDPE-g-OA, prepared by maintaining the temperature at 170degreesC and the roller speed at 80 rpm, was about 6 wt %. It was found that both LDPE and LDPE-g-OA were pseudoplastic fluids. OA was grafted onto LDPE in the form of a monomer and a dimer. The grafted LDPE is expected to act as a compatibilizer between starch and polyethylene. (C) 2003 Wiley Periodicals, Inc.