engleski

FREE-RADICAL INITIATED POLYMERIZATION OF N-METHACRYL-N, N'-DIISOPROPYLUREA WITH STYRENE

Free-radical initiated copolymerization of N-methacryl-N, N'-diisopropylurea (MA-DiPrU) with styrene (St) was performed to low conversion by using dibenzoyl peroxide (Bz2O2) in butanone at 70oC. The copolymer composition was calculated on the basis of nitrogen content in copolymers. The reactivity ratios determined by the Kelen-Tüdös method are: r1( MA-DiPrU) = 0.39 and r2(St) = 1.03. In all cases regardless of the monomer-to-monomer ratios in the feed, an excess of St was present in copolymers. Copolymers decompose under TGA conditions in nitrogen by a two step mechanism. In the first step between 180oC and 250oC, isopropylisocyanate (iPrNCO) separates by degradation of diisopropylurea in the side chain. The thermally stable residue represents the copolymer of methacryl-isopropylamide ((MA-iPrU) with St, which decomposes by a one-step mechanism between 280oC and 450oC.

Methacryl-N; N'-Diisopropylurea; Styrene; Poly(methacryl-isopropylurea-co-styrene); Poly(methacryl-isopropylamide-co-styrene); Thermal properties; Thermal degradation; Isopropylisocyanate.

nije evidentirano