title: Copolymers of vinyl-containing benzoxazine with vinyl monomers as precursors for high performance thermosets.
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 oligo(P-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.
authors: Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan. takeichi@ens.tut.ac.jp.
authors: Tsutomu
authors: T
authors: Takeichi
authors: Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan. detto_me@yahoo.com.
authors: Soulideth
authors: S
authors: Thongpradith
authors: Department of Environmental and Life Sciences, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580, Japan. kawauchi.t.aa@m.titech.ac.jp.
authors: Takehiro
authors: T
authors: Kawauchi
mesh_terms: D048588:Benzoxazines / Q000737:chemistry*; D004548:Elasticity; D015394:Molecular Structure; D008970:Molecular Weight; D019906:Nuclear Magnetic Resonance, Biomolecular; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014783:Viscosity
chemical_list: D048588:Benzoxazines; D011108:Polymers