Synthesis and characterization of comb-polymers with controlled structure

[摘要] Synthesis of a series of poly (methylmethacrylate)-graft-poly (styrene) polymer wascarried out via free radical polymerization of methylmethacrylate and polystyrenemacromonomers. The macromonomers were synthesized via living anionicpolymerization techniques. Two series of macromonomers where synthesized withdifferent polymerizable end group functionalities, by termination with p-vinyl benzylchloride and 3-(dimethyl chloro silyl) propyl methacrylate. The branch density was variedby controlling the composition feed ratio of the macromonomers to comonomer. Liquidchromatographic techniques were used to fully characterize the chemical compositionand branch distributions of the graft polymer. Liquid chromatography under criticalconditions of adsorption of styrene coupling with Fourier Transform Infrared Spectra wasused to investigate the chemical composition and distribution of the branches in thegraft. Physical properties of the graft copolymers such as Tg and free volume weredetermined using differential scanning calorimetry and positron lifetime spectrometryrespectively. The relationship between the chemical composition and the graftcopolymer properties such as Tg and free volume were investigated. The results showthat for long chain macromonomers phase segregation occurs in the graft copolymers. Inthe case of shorter chain macromonomers at low content no phase segregation isobserved and the macromonomers have an antiplasticization effect on the graftpolymers.

[发布机构] Stellenbosch University