Radical polymerization of N‐phenyl‐α‐methylene‐β‐lactam

N‐phenyl‐α‐methylene‐β‐lactam (PML), a cyclic analog of N,N‐disubstituted methacrylamides which do not undergo radical homopolymerization, was synthesized and polymerized with α,α′‐azobis (isobutyronitrile) (AIBN) in solution. Poly (PML) (PPML) is readily soluble in tetrahydrofuran, chloroform, pyridine, and polar aprotic solvents but insoluble in toluene, ethyl acetate, and methanol. PPML obtained by radical initiation is highly syndiotactic (rr = 92%), exhibits a glass transition at 180°C, and loses no weight upto 330°C in nitrogen. The kinetics of PML homo‐polymerization with AIBN was investigated in N‐methyl‐2‐pyrrolidone. The rate of polymerization (Rp) can be expressed by Rp = k[AIBN]0.55[PML]1.2 and the overall activation energy has been calculated to be 87.3 kJ/mol. Monomer reactivity ratios in copolymerization of PML (M2) with styrene (M1) are r1 = 0.67 and r2 = 0.41, from which Q and e values of PML are calculated as 0.60 and 0.33, respectively. Copyright © 1990 John Wiley & Sons, Inc.