Kinetics and mechanism of grafting of oleic acid onto acrylonitrile-butadiene-styrene terpolymer

The graft copolymerization of oleic acid onto acrylonitrile-butadiene-styrene (ABS) terpolymer was initiated by benzoyl peroxide (BPO) in 1,2-dichloroethane solution. The infrared spectra confirmed that oleic acid was successfully grafted onto ABS backbone. The influences of the concentration of oleic acid, BPO and ABS on grafting were studied. The grafting occurred at the butadiene region of ABS. A reaction mechanism has been proposed; grafting most probably took place by cross-termination of oleic acid radicals with ABS macroradicals. Monomer cage effect on grafting was observed to depend on the 1.3 power of monomer concentration from the experimental results of initial rate of graft copolymerization. The initial rate of graft copolymerization (Rp) could be written as: Rp=1.61×10−4[M]2.3[P][I2]/([M]2.3+0.53[P])2, where [M], [P], [I2] denote the concentration of monomer, polymer and initiator, respectively.