Development and characterization of mesoporous terpolyimide nanocomposites with low dielectric constant

Abstract

Polyimides are a sophisticated family of materials, which cover an exhaustive range of high performance polymers. They find applications in highly technical end use fields from aerospace to microelectronics. Their strength and resistance to heat and chemicals are so great that these materials often replace glass and metals such as steel, in many demanding industrial applications. The scope of the present investigation was to synthesize terpolyimides with low dielectric constant without comprising thermal and mechanical properties. In this context, in the present study two different systems of terpolyimides were synthesized. The first system of terpolyimides was synthesized by combining dianhydrides such as 3,3 ,4,4 -biphenyl dianhydride (BPDA), 3,3 ,4,4 -benzophenonetetracaboxylic dianhydride (BTDA) and 3,3 ,4,4 -oxydiphthalicdianhydride (ODPA) with a diamine 4,4 -oxydianiline (ODA). The second system of terpolyimides was synthesized by combining BPDA, BTDA and 4,4 -(hexafluoroisopropylidene) diphthalicanhydride (6FDA) with ODA. Their hompolyimides and copolyimides were also synthesized for comparison. The first system of terpolyimides showed enhanced thermal stability, high tensile strength and tensile modulus compared to the second system of terpolyimides. The dielectric constants of the former were also higher than the latter. Though the second system of terpolyimides showed low dielectric constant, their thermal and mechanical properties were poor. As a result of functionalization their surface areas were also reduced. As the pore diameter of APTS-KIT-6 was larger than APTS-SBA-15, it could trap more air in it and further reduce dielectric constant.