Preparation And Properties Of Benzoxazine-based Low Dielectric Materials

1.Fluorinatedaniline-basedbenzoxazine?AF-BOZ?andfluorinated amine-terminated benzoxazine?AF-DBOZ?were synthesized by Mannich reaction of aniline and amino-terminated polyether?D-400?with bisphenol AF and polyformaldehyde respectively.Two benzoxazine monomers and their blends with epoxy resin were cured by heating.Its chemical structure,curing behavior,thermal stability and dielectric properties were characterized and tested by FTIR,NMR,DSC,TGA and Vector Network Analyzer.The results showed that under N₂ condition,the temperature of 5%mass loss of poly?AF-BOZ?was 366?,and the residual carbon rate at 800? was 58%.Poly?AF-BOZ?had better thermal stability and lower dielectric constant that was 2.68 than AF-BOZ/E51 blend cured product.The temperature of 5%mass loss temperature of poly?AF-DBOZ?was 257?,and the residual carbon rate at800? was 58%.Poly?AF-DBOZ?had lower thermal stability than AF-DBOZ/E51blend cured product,but a lower dielectric constan that was 2.84.2.Fluorinated ethanolamine-based benzoxazine?AF-EBOZ?was synthesized by using ethanolamine,polyformaldehyde and bisphenol AF as raw materials,then polyurea prepolymer was synthesized by using terminal amino polyether?D-400?and diphenylmethane diisocyanate?MDI?and mixed with it,and the polymer was formed by heating and curing.The chemical structures of benzoxazine were characterized by FTIR and NMR.The curing behavior was analyzed by DSC.The thermal stability of the cured product was analyzed by TGA,with the dielectric constant measured.The results show that AF-BOZ/PU had better toughness and a lower dielectric constant that was 2.92than poly?AF-EBOZ?.3.Dicyclopentadiene-based phenolic monomer?DCPDNO?was synthesized by Friedel-Crafts reaction using dicyclopentadiene and phenol as raw materials.The resulting DCPDNO was reacted with paraformaldehyde and aniline to synthesize dicyclopentadiene-based benzoxazine?DCPD-BOZ?,which was mixed with epoxy resin,and then cured at high temperature.Its chemical structure,curing behavior,thermal stability and dielectric properties were characterized and tested by FTIR,NMR,DSC,TGA and Vector Network Analyzer.The results showed that DCPD-BOZ had a curing peak at 207?.Under N₂ condition,poly?DCPD-BOZ?had a 5%mass loss temperature of 305?,and had the fastest thermal decomposition rate at 390?.The residual carbon rate at 800? was 35%.Its dielectric constant at room temperature was 2.96,and dissipation factor was 0.019.The DCPD-BOZ/E51 blend showed a reaction peak at 240? and the DCPD-BOZ/E51 blend cured product had a mass loss temperature of 367? under 5%,Increased by 61?.4.The intermediate monomer dicyclopentene-furanmethylamine?DCPD-F?was firstly synthesized by Diels-Alder reaction using dicyclopentadiene and furanmethylamine as raw materials.and then the synthesized?DCPD-F?and bisphenol A and formaldehyde were used as raw materials through Mannich reaction to synthesize a benzoxazine?DCPD-F-BOZ?with bridged rings structure,which was cured at high temperature to form a thermosetting resin.The chemical structure of DCPD-F and DCPD-F-BOZ was characterized by FTIR and NMR.The curing behavior of DCPD-F-BOZ was characterized by DSC with two peaks at about 223? and 258? appeared during its curing,respectively.The themal stability of poly?DCPD-F-BOZ?was analyzed by TGA,with the dielectric constant being tested.The results showed that poly?DCPD-F-BOZ?had excellent thermal stability under the condition of nitrogen,which began to decompose at 360? with 5%mass loss temperature of 382?.The char yield rate at 800? was 53%and the dielectric constant at room temperature was 2.96.