EFFECT OF BIS-IMIDE ADDITIVES ON DIELECTRIC-CONSTANT OF POLYIMIDES

Three types of low molecular weight bis-imide additives containing flu orine and siloxane were synthesized. The effects of the additives for polyimides on dielectric constant, thermal, and mechanical properties were studied. The addition of these additives for aromatic polyimide l owered the dielectric constant of the polyimide with increasing the am ount of the additives up to 10 wt%. However, the addition of additives with more than 10 wt% did not show any further effect. Bis-imide addi tives containing fluorine were more effective than the bis-imide addit ive containing siloxane to lower the dielectric constant for polyimide . In contrast, the additives did not show any effect on lowering diele ctric constant for siloxane-imide block copolymer with microphase sepa rated structure. The glass transition temperature (T-g), thermal decom position temperature (T-d), tensile modulus (TM), tensile strength, an d elongation were lowered with increasing the amount of additives for aromatic polyimide, while T-g, T-d, and TM were slightly increased by the addition of fluorine containing additives for siloxan-imide block copolymer. It was found that the effect of additive into the polyimide on dielectric constant, thermal, and mechanical properties was differ ent according to the structure of the polyimide.