Reaction of aluminium chloride with poly(divinyl benzene) particles - a reaction kinetic study using infrared spectroscopy

Porous poly(para-divinylbenzene) and poly(meta-divinylbenzene) particles we re synthesised from para-divinylbenzene and meta-divinylbenzene monomers wi th toluene and 2-ethylhexanoic acid as porogens. The residual vinyl groups in the particles were thereafter reacted using aluminium chloride with dich lorobenzene as a catalyst. The conversion of vinyl groups was followed by a nalysing polymer particles taken from the reaction mixture at different tim e intervals. Infrared spectroscopy both in the mid and near infrared region was used as the analytical technique. The intensity changes in the overton e absorption at 1628 nm due to the vinyl bonds were used as the basis for t he quantification of the vinyl group consumption. Infrared spectra of the p articles in the mid IR were also measured to understand changes taking plac e in the polymer matrix during the reaction. The results indicated that res idual vinyl groups in these polymer particles were consumed during the reac tion with aluminium chloride. The reaction of aluminium chloride with the p olymer matrix was explained by proposing mechanisms for the formation of di fferent products during the reaction. The complex formed between aluminium chloride and the residual vinyl groups seemed to induce addition of HCl to the vinyl group or leads to crosslinking and/or cyclisation in the case pol y(para-DVB) particles. The reaction of aluminium chloride with poly(meta-DV B) takes place to a lesser extent. (C) 1999 Elsevier Science B.V. All right s reserved.