Synthesis and properties of linear chloroacetylated polystyrene

Polystyrene (PS) was synthesized by emulsion polymerization. The linear chloroacetylated PS was prepared high effectively by Friedel-Crafts acetylation of PS using chloroacetyl chloride and anhydrous aluminium chloride as chloroacetylation reagent and catalysts, respectively. The structure of chloroacetyl group is similar to that of chloromethyl group. In this method, carcinogenic compound (chloromethyl ether etc.) was avoided and the reactions of secondary cross link and multi-substitute could be eliminated. The resultant polymers were characterized by Fourier transform infrared spectrometery (FTIR) and thermogravimetric analysis. The effects of reaction conditions on chloroacetylation were studied, and the optimum reaction conditions were obtained. Chloroacetyl group was introduced into benzene ring of PS because of the appearance of the absorption peaks at 1695cm(-1) (due to C=O bonds) and 644cm(-1) (due to C-Cl bonds) in the FTIR spectrum. The thermal stability of the chloroacetylated PS was decreased with increasing chloroacetyl group. Moreover, there were two decomposing stages. The glass transition temperature of chloroacetylated PS increased with substitution value increasing. The effects of the reaction conditions such as reaction temperature, the solvent amount and the concentration of chloroacetyl chloride and anhydrous aluminium chloride on the chloroacetylation of PS were obvious. The certain loading can be controlled when it is lower than the maximum loading of chloroacetylated PS. The reaction condition is gentle and the operation is safe, simple and economical so that Friedel-Crafts acetylation of PS is an ideal reaction method.