synopsisDiphenyl-, phenylethyl, and phenylmethylketene have been copolymerized with phenyl isocyanate by use of sodium naphthalene in dimethylformamide (DMF) a t -45°C. Reactivity ratios of phenyl isocyanate (TZ) with diphenylketene (TI) were rl = 0.10,rz = 0.29; with phenylethylketene (rl) were TI = 1.6, r2 = 0.10; and with phenyl methyl ketene (TI) were rl = 4.8, ~2 = 0.02. The same initiator and solvent system were used for homopolymerization of phenylethylketene and copolymerization with m-chloro-, pchloro-, p-methoxy-, and m-methoxyphenyl isocyanate as well as with phenyl isocyanate. Molecular weights rangeafrom 1740 to 4000. The effect of substituents on the order of isocyanate incorporation into the copolymer was m-C1 = p-C1> m-Me0 > H > p-MeO.Phenylethylketene was also copolymerized with m-methoxyphenyl, p-methoxyphenyl, and p-tolyl isocyanate in tetrahydrofuran (THF) a t -78°C. Molecular weights ranged from 2800 to 10,500. The least reactive isocyanate was incorporated into the copolymer to a greater extent in this solvent than in the more polar DMF. DTA showed the presence of crystallinity only in polymers of high isocyanate content. The ketenes copolymerized less readily with alkyl isocyanate, such as ethyl, n-butyl, nhexyl, and cyclohexyl isocyanate, than with the aromatic isocyanates when sodium naphthalene was used in either DMF or THF.
Copolymers of p‐vinylphenol were prepared in bulk with heptafluorobutyl and pentadecafluorooctyl acrylates and trifluoroethyl, hexafluoroisopropyl, heptafluorobutyl, octafluoropentyl and pentadecafluorooctyl methacrylates using azobisisobutyronitrile as the initiator in sealed tubes. Intrinsic viscosities of the copolymers ranged from 0.44 to 1.85. Monomer reactivity ratios for copolymers of trifluoroethyl methacrylate (M1) were: with hydroxyethyl methacrylate (M2), r1 = 0.47, r2 = 1.0; with methyl methacrylate (M2), r1 = 0.82, r2 = 0.50; with styrene (M2), r1 = 0.29, r2, = 0.20; and with p‐vinylphenol (M2), r1 = 0.096, r2 = 1.5. Q and e values of trifluoroethyl methacrylate were 1.30 and 0.92, respectively. Monomer reactivity ratios of octafluoropentyl methacrylate (M1) were: with styrene (M2), r1 = 0.26, r2 = 0.20; and with p‐vinylphenol, r1 = 0.21, r2 = 1.5. Q and e values for octafluoropentyl methacrylate were 1.27 and 0.92, respectively. Critical surface tensions of the homopolymers ranged from 17.9 to 14.8 dyn/cm. A copolymer of hexafluoro‐i‐propyl methacrylate and p‐vinylphenol exhibited a critical surface tension of 16.5 dyn/cm.
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