RADICAL POLYMERIZATION OF 4-METHYLENE-4H-1,3-BENZODIOXIN-2-ONES - CYCLIC ALPHA-SUBSTITUTED STYRENES

4-Methylene-4H-1,3-benzodioxin-2-one (MBDOON), an a-substituted cyclic styrene derivative, was synthesized and polymerized readily with 2,2' -azobis (isobutyronitrile) (AIBN) as an initiator in solution. The kin etics of the MBDOON homopolymerization with AIBN was investigated in N -methyl-2-pyrrolidone (NMP). The rate of polymerization, R(p), can be expressed by R(p) = k[AIBN]0.52[MBDOON]1.1 and the overall activation energy has been calculated to be 75.7 kJ/mol. Monomer reactivity ratio s in copolymerization of MBDOON (M2) with styrene (M1) are r1 = 0.31 a nd r2 = 3.20, from which Q and e values of MBDOON can be calculated as 3.0 and -0.7, respectively. Ring-substituted MBDOON monomers such as 6-chloro, 6-methyl, and 7-methoxy derivatives were synthesized and pol ymerized with AIBN. The 6-substituted MBDOON's readily underwent radic al polymerization while the 7-methoxy-MBDOON was slower to polymerize. Poly(MBDOON) is predominantly heterotactic. (rr = 35, mr = 46, and mm = 19%). The polymer releases carbon dioxide at about 200-degrees-C an d is converted with some depolymerization to poly[(o-hydroxyphenyl) ac etylene]. The thermolysis temperature is very much affected by the rin g substituent. The onset of carbon dioxide liberation was observed at 140-degrees-C in the case of the 7-methoxyl derivative while the 6-sub stituents had a smaller effect on the decarboxylation temperature.