Polyimide‐silica nanocomposites exhibiting low thermal expansion coefficient and water absorption from surface‐modified silica

Abstract

In this study, a commercially available nano-sized silica (SiO 2 ) was surface-modified via esterification with oleic acid (OA), a relatively inexpensive and hydrophobic modifier, and characterized by FTIR, NMR, SEM, EDS, and TGA measurements. Various amounts of the surface-modified silica nanoparticles (SiO 2 -OA) were dispersed in a poly(amic acid), which were then cyclized at high temperatures to form a series of PI/SiO 2 -OA nanocomposite films (PISA). The effect of the addition of the SiO 2 -OA nanoparticles on the properties of the as-prepared polyimide nanocomposite was studied. The results indicated that, comparing with pure PI and PI/pristineSiO 2 composite film (PISI), the as-prepared PISA films had enhanced dynamic mechanical properties and thermal stability, as well as reduced water absorption and thermal expansion. The as-prepared PI/SiO 2 -OA nanocomposites have potential for applications in high performance microelectronic devices.

Thermal and mechanical properties of stretched recyclable polyimide film

“…6 Physical methods such as sand blasting or flame, corona and UV rays' treatments were also considered by various researchers. [6][7][8][9][10][11][12][13][14][15] However, the main disadvantage of using the above approaches is that the resulting PI materials are in general brittle, which will be more difficult for processing. 8,[16][17][18] A conventional way of improving the mechanical properties of polymer films is by stretching.…”

Synthesis and Characterization of Fluorinated Polyimide/Silica Nanocomposites with Low Water Absorption and Dielectric Constant

“…For example, fluorination can impart the resulting fluorinated polyamides with the decreased dielectric constants because of the lower polarizability of fluorine [9][10][11] . On the other hand, the polyimide/SiO2 composites have been found to exhibit the good thermal properties 12,13 , low humidity absorption 14 , decreased dielectric constant 15 and improved optical properties 16 . More importantly, the introduction of silica into polyimide films could increase the hydrophobicity, reducing the humidity absorption with a lower dielectric constant reached 17 .…”

Preparation and Performance of Nano-hybrids Synthesized from Polyimide and Silica

“…In this situation, PI-silica hybrid prepared by in-situ sol-gel process will be an excellent approach to improve thermal stability, tensile modulus and CTE of PI due to high thermal stability and rigidity of silica. Till now, much research has carried out to develop the properties of PI [4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Among the PIs, rigid PI from BPDA and PDA (Scheme 1) is a unique type of PI because of its high modulus, increased tensile modulus by cold drawing, remarkable spontaneous in-plane orientation, low water sorption, low stress relaxation co-efficient and minimum coefficient of thermal expansion [18][19][20][21].…”