Copolymers of Vinyl-Containing Benzoxazine with Vinyl Monomers as Precursors for High Performance ThermosetsReportar como inadecuado




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Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan





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Academic Editor: Atsushi Sudo

Abstract A benzoxazine containing a vinyl group P-4va was prepared by the reaction of phenol, 4-vinylaniline, and paraformaldehyde. A differential scanning calorimetry DSC study revealed that ring-opening polymerization of the benzoxazine and chain polymerization of the vinyl group occurred in the same temperature range. When 2,2-azobisisobutyronitrile was added as a radical initiator to P-4va, however, only the vinyl groups were polymerized at lower temperature, giving oligoP-4va that contains pendent benzoxazine units. Radical copolymerization of P-4va with various vinyl monomers such as styrene, methyl methacrylate MMA, and n-butyl acrylate BuA was examined. The chemical structure of the copolymers was confirmed by FT-IR and 1H-NMR to be one of polyolefins bearing benzoxazine units as the pendant groups. The weight-average molecular weights of the copolymers determined by size exclusion chromatography were to be in the range of 1900–51,500 depending on the comonomers. DSC of the copolymers showed that the maxima of the exothermic peaks corresponding to the ring-opening polymerization of the pendent benzoxazine units were observed in the temperature range of 229–250 °C. Thermal cure up to 240 °C of the copolymer films afforded homogenous transparent films with improved thermal properties. Tough cured film was obtained by the copolymerization with MMA, while a tough and flexible film was obtained by the copolymerization with BuA. View Full-Text

Keywords: benzoxazine; vinyl monomer; radical polymerization; high molecular weight benzoxazine; ring-opening polymerization benzoxazine; vinyl monomer; radical polymerization; high molecular weight benzoxazine; ring-opening polymerization





Autor: Tsutomu Takeichi * , Soulideth Thongpradith and Takehiro Kawauchi

Fuente: http://mdpi.com/



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