Preparation, characterization,and thermal properties of hydrophilic copolymers: p-chlorophenylmaleimides with hydroxylethyl methacrylate and beta-methyl itaconate

摘要

This work describes the synthesis, characterization, and thermal behavior of copolymers of p-chlorophenylmaleimide (Cl-PhMI) with beta-methyl itaconate (beta-MHI) and 2-hydroxyethyl methacrylate (HEMA). Copolymerization was carried out with a radical initiator by varying the feed mole fraction of Cl-PhMI from 0.25 to 0.75. The copolymer composition was determined from the N/C ratio based on elemental analysis data and with ~1H NMR spectroscopy for poly(Cl-PhMI-co-HEMA) using a proton signal attributed to the -CH3 of HEMA (delta = 0.7-1.4ppm) and the area of aromatic ring protons (delta = 7.2-7.8ppm), where the proton/area relationship confirmed the copolymer compositions calculated by elemental analysis. The monomer reactivity ratios r_1 and r_2 were determined using the Kelen-Tudos method. These values demonstrated that copolymerization produced random copolymers with an alternation tendency. The molecular weight and polydispersity were also determined. The thermal behavior can be correlated with the copolymer composition. An increase of the thermal decomposition temperature occurred when the content of Cl-PhMI increased. The glass transition temperature and thermal stability of poly(beta-MHI) or poly(HEMA) increased with an increasing amount of Cl-PhMI in the polymer backbone.