Synthesis of Poly(styrene)- g -Poly(oleic acid) Graft Copolymers via Reversible Addition/Fragmentation Transfer (RAFT) Polymerization Using a Poly Oleic Acid Macro-RAFT Agent

In this study, a new polymeric oleic acid-derived macro addition/fragmentation transfer agent was utilized to produce a poly(styrene)- g -poly(oleic acid) graft copolymer. The double bond of oleic acid was initially saturated with bromine and the condensation polymerization between the carboxylic acid and the bromide resulted in polyoleic acid with pendant bromide groups. Xanthate groups were exchanged with the bromide groups to obtain the poly(oleic acid) macro RAFT agent (Pole-Xa). Poly(styrene)- g -poly(oleic acid) (PS- g -Pole) graft copolymers were synthesized via reversible addition fragmentation transfer (RAFT) polymerization of styrene and the reaction was evaluated in view of the polymerization kinetics. The effects of polymerization temperature and reaction time on graft copolymer yield, conversion and molecular weight were investigated. In the RAFT polymerization of styrene, the rate constant (k) was found to be 1.83 × 10 –3 L/mol/dk and 7.27 × 10 –4 L/mol/dk for the polymerization temperatures of 80 and 90 °C, respectively. The structural characteristics and thermal properties of the obtained products were characterized using FT-IR, 1 H-NMR, GPC, TGA, DSC and SEM–EDX.