Abstract
<p>The radical terpolymerization reactions of the acceptor-donor-acceptor and donor-acceptor-donor systems, maleic anhydride (MA)-allyl propionate (AP)-methyl methacrylate (MMA) and styrene (St)-MMA-AP, had been studied. The terpolymerizations were carried out in methyl ethyl ketone at 60-75 °C in the presence of 2,2’-azoisobutyronitrile (ABIN) used as the initiator. Some kinetic parameters and copolymerization constants - for both, system were determined by dilatometric and Kelen-Tudos or Seiner-Lift methods. The obtained results are discussed in terms of the free monomer and complex chain growth models. It is shown that terpolymerization was carried out at a stage close to binary copolymerization of MA...AP complex with free MMA and St...MMA complex with AP in the both studied system, respectively. These systems are also used as model for interpretation of cyclocopolymerization mechanism in allyl methactylate-MA (or St) system. DTA and TGA analyses indicated the relatively high thermal stability of St-MMA-AP terpolymer. It is shown that this terpolymer decomposes through a one-step reaction at 310 °C, however MA-AP-MMA terpolymer decomposes through a multi-step reactions at 150, 260 and 310 °C.</p>
Highlights
Ternary monomer systems in terms of the conjugation type in monomer molecule and the mechanism of chain growth can be classified by following groups: (a) donor (D1)-donor (D2)-donor (D3), (b) acceptor (A1)-acceptor (A2)-acceptor (A3), (c) donor (D1)-acceptor (A)-donor (D2) and (d) acceptor (A1)donor (D)-acceptor (A2)
In several publications some attention has been focused on the study of monomer charge transfer complexes (CTC) effect in radical terpolymerization by using following donor-acceptor ternary systems: maleic anhydride(MA)-styrene(St)-methacrylates [9], MA-St-N-phenylmaleimide [10,11], MA-St-citraconic anhydride [12], MA-St-vinylacetate [13], MA-trans-stilbene-phenanthrene [11,14], MAallyl-glycigyl ether-methyl methacrylate [15] and other systems containing MA [5,11]
From the donor-acceptor properties of monomers for ternary systems studied, one can predict that the formation of equimolecular (1 : 1) CTC’s as follows: Kc
Summary
Ternary monomer systems in terms of the conjugation type in monomer molecule and the mechanism of chain growth can be classified by following groups: (a) donor (D1)-donor (D2)-donor (D3), (b) acceptor (A1)-acceptor (A2)-acceptor (A3), (c) donor (D1)-acceptor (A)-donor (D2) and (d) acceptor (A1)donor (D)-acceptor (A2). Complex-formation not take placed in the (a) and (b) systems monomers of which have similar type of double bound conjugation. Reaction submited to usual equations of random copolymerization and differed by complexity in term of the «controlling» by radical reactions of chain growth. (c) and (d) monomer systems comprised donor-acceptor monomers which can be presented by two D...A1 and D...A2 complexes for (c) system and A...D1 and A...D2 complexes for (d) system in propagation reactions. Number of elementary chain growth reactions in these ternary systems depended on complex formation and homopolymerization properties of comonomers in given terpolymerization conditions
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