| Polybenzoxazines is a new type of thermosetting phenolic resin that obtained by the ring-opening polymerization of benzoxazine monomers. They possess the traditional properties of phenolic resins and the unique characteristics that phenolic resins don't have. However, the disadvantage of brittleness limits the applications of benzoxazine resin. In order to improve the comprehensive properties of PBOZ resin, benzoxazines containing imide groups were designed and synthesized. The toughness of PBOZ resin improved by adding polymethyl phenylsiloxane containing epoxy group (EPMPS)were investigated. The carbon fiber/epoxy phenyl silicone/polystyrene and oxazine (CF/EPMPS/PBOZ) composite material were prepared and their performances were tested.Firstly, non-isothermal DSC method was used to analysis the curing kinetics of benzoxazine resin, the curing kinetics of the M-BOZ were confirmed by the n, m-class reaction and the results showed that the reaction M-BOZ resin curing kinetics of m-order reaction model was better than the n-reaction model. The effects of curing temperature and heating rate on EPMPS/BOZ resin were investigated and obtained the best curing conditions of EPMPS/BOZ:180℃/2h+200℃/2h+220℃/1h. The flow of EPMPS/BOZ resin was tested by rheometer, and the curing process was further guidanced.Then M-benzoxazine and epoxy resin, poly-methyl-phenyl-terminated silicone oil were mixed by the method of organic solvent. to mix two polymers, EPMPS/BOZ resin was obtained after the removal of the solvent and then EPMPS/PBOZ resin specimens were obtained by casting molded. The CF/EPMPS/PBOZ composites could be obtained by the use of flat plate vulcanizing machine after compositing of EPMPS/BOZ resin and carbon fiber.Before and after curing of the resin was compared by infrared spectroscopy testing. The mechanical properties results of EPMPS/PBOZ resin show that EPMPS/PBOZ resin impact strength and flexural strength were increased by 46.4% and 33.6% respectively when the content of EPMPS was 10 wt% which can play a good toughening effect but decreased the flexural modulus. The thermal analysis of EPMPS/PBOZ showed that the heat resistance of the BOZ resin did not change with the addition of EPMPS. The dynamic viscoelastic properties of EPMPS/PBOZ were tested by DMA and the result showed that the glass transition temperature increased by 3℃when the content of EPMPS was 10 wt%. The section morphology of the EPMPS/PBOZ resin and mechanical properties of CF/EPMPS/ PBOZ composite materials were tested when the content of EPMPS was 10 wt%. |
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