Synthesis And Application Of Benzoxazine Resin

As one of the hottest research topics in the field of flame retardant insulating materials,benzoxazine has received widespread attentions by researchers,due to its good heat resistance and flame retardance.There will be no low molecular released during the resin curing process.In this paper,the benzoxazine resin with triazine structure and three oxazine rings was synthesized by formaldehyde,melamine and phenol,in order to improve the charring and flame retardant properties of the resin.The results of the synthesis process investigation on benzoxazine resin showed that the benzoxazine resin would have the fastest curing speed with the optimal synthesis conditions listed as follow:the molar ratio of formaldehyde,melamine and phenol was 6.5:1:3,reaction temperature and time of formaldehyde and melamine was 70?/35 min,then added phenol,the reaction mixture was stirred at 94? for 3.5 h.The structure of the benzoxazine resin were characterized by FT-IR spectra and 1H-NMR.The cured resin was characterized by TG-DSC-MS and EDS,to analyze the flame retardant mechanism of benzoxazine resin.FT-IR spectrum confirmed that the production was benzoxazine resin.The results showed that NO2,CO2,H2O and a little of CO were released during the thermal decomposing.A triazine structure layer covered the surface of the the cured resin after combusted.In this paper,laminate board was also prepared by thermo forming using benzoxazine and expoy resin as matrix resin,glass fiber cloth as reinforcing material.The best content of benzoxazine resin in matrix resin and the integrated performance of the laminate board was studied.The results show that the oxygen index of the laminate board was 21%when the mass ratio of benzoxazine and expoy resin was 1:1,and the self-extinguishing time was 148",the UL-94 vertical burning test ranking of V-1 was obtained.The transverse bending strength of the laminate board was 450.7 MPa,and the longitudinal bending strength was 465.5 MPa,the relative permittivity was 3.463,and the loss tangent was 0.0046.Mg(OH)2 fillers were added into matrix resin in order to improve the flame retardance of the laminate board.Results indicated that the flame retardance was influenced by the amount of power and the particle size of Mg(OH)2.Moreover,the hybrid fillers filled also have influence on the integrated performance of the composites.The results also showed that the oxygen index of the laminate board was 34%,when the content of Mg(OH)2 was 30 wt%and the mass ratio of YX-105 and YX-110 was 1:2.The self-extinguishing time was 49"81,the UL-94 vertical burning test ranking of V-0 was obtained.The transverse bending strength was 410.1 Mpa,the longitudinal bending strength was 398.6 Mpa,the relative permittivity was 3.99,and the loss tangent is 0.0046.This kind of laminate board will has a wide application prospect in the field of flame retardant copper clad laminate materials.