engleski

Synthesis and polymerization of N-acryl-dicyclohexylurea and N-methacryl-dicyclohexylurea and copolymerization with alpha-methylstyrene

The title compounds have been prepared by the addition of acrylic acid and methacrylic acid to dicyclohexylcarbodiimide (DCC). N-Acryl-N, N´-dicyclohexylurea (Acryl-DCU) homopolymerizes and copolymerizes with a-methylstyrene (aMeSt), while Methacryl-DCU does not polymerize under the standard free-radical-initiated polymerization. Copolymers of Acryl-DCU with aMeSt prepared under different monomer-to-monomer ratios in the feed have random composition with an azeotropic point at ratio of 0.75 (Acryl-DCU) to 0.25 (aMeSt). Reactivity ratios determined by the Kelen-Tüdös method are r1 (Acryl-DCU) = 0.72 and r2 (aMeSt) = 0.07. Poly(Acryl-DCU) and copolymers with aMeSt decompose under the TGA conditions by a two step mechanism. In the first step between 180 and 250°C, cyclohexylisocyanate separates by degradation of dicyclohexylurea in the side chain, while the thermally stable residue represents the poly(cyclohexylacrylamide) and copolymers with aMeSt.

acryl-dicyclohexylurea; metacryl-dicyclohexylurea; poly(acryl- dicyclohexylurea); poly(acryl-dicyclohexylurea-co-aMeSt); poly(cyclohexylacrylamide); poly(cyclohexylacrylamide-co-aMeSt); reactivity ratios; rate of copolymerization; mechanism of thermal deg

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