Characterization and mechanism study of aqueous cationic polymerization of p-methylstyrene

Aqueous cationic polymerization has attracted considerable interest as a novel polymerization technique, because it conforms to the "green chemistry" trend and challenges the concept of traditional cationic polymerization. In this paper, a CumOH/B(C₆F₅)₃/Et₂O system was used to initiate the aqueous polymerization of p-methylstyrene through suspension and emulsion methods. Several types of surfactants were used, including the cationic surfactant CTAB, non-ionic surfactant NP-40, and anionic surfactant SDBS, and the influences of initiator concentration and temperature on polymerization were investigated. Consistent with previous literature, initiator activity was positively correlated with temperature unlike in traditional cationic polymerization. Gaussian 09W simulation software was used to calculate and optimize changes in the bond lengths and angles of B(C₆F₅)₃ after ether was added to the system. The addition of ether increased the polarity of B(C₆F₅)₃, rendering it soluble in water. ¹H-NMR was used in identifying the main chain and terminal structures of the polymer, and the mechanism of p-methylstyrene aqueous phase cationic polymerization was proposed.