Copolymerization of methyl 2-acetamidoacrylate and styrene in the presence of stannic chloride

Continuous variation method in UV revealed that methyl N-acetylaminoacrylate (MNA) and SnCl4 formed the 1:1 complex. The copolymerization of MNA with styrene in tetrahydrofuran was carried out at 50 degreesC in the presence of SnCl4. The resulting monomer reactivity ratios decreased with an increasing concentration of SnCl4 added. This finding suggests that SnCl4 participates in the propagation step of the copolymerization. Therefore, the copolymerization was analyzed by assuming terpolymerization of free MNA (M-1), complexed MNA (M-2) and styrene (M-3). The absolute copolymerization parameters were obtained as follows: k(11)/k(12) = 0.165, k(11)/k(13) = 3.04, k(22)/k(21) = 0.32, k(22)/k(23) = 0.103, k(33)/k(31) = 0.058, k(33)/k(32) = 0.001, Q(1), = 6.03, e(1) = 0.52, Q(2) = 88.57, and e(2) = 2.23. The complexed MNA is more reactive to polymer radicals with free MNA and styrene as the terminal unit than the free MNA. Very small values of k22/k23 and k(33)/k(32) suggests that the copolymerization of the complexed MNA and styrene proceeds alternatingly. (C) 2001 Elsevier Science Ltd. All rights reserved.