A Kinetic Study of Block Copolymerization of Poly(diethylene glycol phthalic anhydride) and Methyl Acrylate

Aredox system of potassium diperiodatocuprate (III) (DPC)/poly(diethylene glycol phthalic anhydride) (PPAG) was employed to initiate block copolymers of methyl acrylate (MA) and PPAG in alkaline medium. Block copolymers with high total conversion were obtained, which indicated that potassium diperiodatocuprate (III)/poly(diethylene glycol phthalic anhydride) redox pair is an efficient initiator for this blocking. The kinetics of block copolymerization and total conversion at different conditions (concentration of reactants, temperature, and concentration of potassium diperiodatocuprate (III), reaction time) were investigated. The results indicated that the best reaction conditions were as follows: reaction time=40 min, reaction temperature =35ºC, concentration of potassium diperiodatocuprate (III)=3.12×10-3 mol/L and the reactants concentration=2.45 mol/L, and the equation of the polymerization rate (Rp) was as follows: Rp=k[methyl acrylate]1.63[potassium diperiodatocuprate (III)/ poly(diethylene glycol phthalic anhydride)]0.67, that the overall activation energy of block polymerization was 44.57 kJ/mol. 1H NMR Spectral analysis and infrared spectra proved that the block copolymers were synthesized successfully, and the molecular weight of the block copolymer was obtained to be 33,000. SEM Micrographs show that there are some interstices and two distinct phases in PMMA-nylon 6 (A), and on the contrary, the interstices and two phases have disappeared in PMMA-block copolymer- nylon 6 (B). The above features suggest that the block copolymer showed greatly improved compatibility of the components between PMMA and nylon 6.