Study On Properties Of BMI Resin Modified By Compounds Containing Ester And Alkenyl Groups

Bismaleimide(BMI)resins are a kind of high performance thermosetting resins,with excellent characteristics such as high-temperature resistance,moist heat resistance,dielectric properties,mechanical properties and processability.Copper-clad laminates made from BMI resin also have the advantages of high temperature resistance,high modulus,good chemical stability,and processability.However,these laminates also have disadvantages of poor toughness,impact strength and dielectric properties.In order to prepare copper clad laminates with high temperature resistance,moist heat resistance,good dielectric properties,low water absorption,etc.In this paper,two monomers containing ester and alkenyl groups were prepared and copolymerized with BMI monomers.The modified BMI resin was used as matrix to prepare copper-clad laminates.The thermal properties,dielectric properties,and adhesion properties of modified BMI resin and copper clad laminates were explored.Two kinds of modifiers(RBOB,LB)were synthesized via S_N2 nuclephilic substitution reaction with 2-allylphenol,4,4'-oxybis(benzoyl chloride)and2-allylphenol,4,4'-biphenyldicarbonyl chloride respectively under certain conditions.The structures of the two monomers were verified by Fourier transform infrared spectroscopy(FT-IR)and Hydrogen nuclear magnetic resonance(~1H NMR).RBOB and LB were used to blend with BMI and the designations RBMI and LBMI which were compared with the DP/BMI resin system,were assigned,respectively.The cure behaviors of resin systems were investigated by DSC and rheological experiment.The DSC curves showed that the curing temperature of RBMI resin system containing propylene group was much lower than that of the DBMI resin system.It is due to the high reactivity of RBMI and new cure reaction mechanism.The rheological behaviors with low viscosities and wide process window of novel BMI resins showed good process-abilities.The thermal properties,dielectric properties and adhesion properties of the two new BMI resin systems were studied.The heat resistances of the two resin systems were investigated using DMA.It was found that the two BMI resin systems had higher glass transition temperatures and good heat resistances.The thermal stabilities of the resin systems were studied by TGA.It was found that the thermal stabilities of the two new resin systems were better than DBMI resin system.The two resin systems exhibited good dielectric properties and the dielectric loss(Tan?:0.002-0.005)was significantly lower than DBMI(Tan?:0.012-0.014).We also studied the tensile shear strength of two BMI resins.It was found that the two BMI resins had good adhesion properties.Copper clad laminates were prepared using RBMI and LBMI resins as substrates,and the thermal properties,dielectric properties,water absorption properties,and adhesion properties of the etched clad laminates were investigated.The copper-clad laminate made from RBMI resin had a high glass transition temperature(Tg:320°C).Both copper-clad laminates had good thermal abilities.The copper-clad laminates also had excellent dielectric properties,low dielectric loss and good water absorption resistance(RBMI:0.9%,LBMI:0.7%).And the high peel strength of copper-clad laminates indicated the excellent adhesion between BMI resins and copper foils.