Preparation and properties of polyimide/silica hybrid composites based on polymer‐modified colloidal silica

Abstract

ABSTRACT:A new type of polyimide/silica (PI/SiO 2 ) hybrid composite films was prepared by blending polymermodified colloidal silica with the semiflexible polyimide. Polyimide was solution-imidized at higher temperature than the glass transition temperature (T g ) using 3,3Ј,4,4Ј-biphenyltetracarboxylic dianhydride (BPDA) and 4,4Ј-diaminodiphenyl ether (ODA). The morphological observation on the prepared hybrid films by scanning electron microscopy (SEM) pointed to the existence of miscible organicinorganic phase, which resulted in improved mechanical properties compared with pure PI. The incorporation of the silica structures in the PI matrix also increased both T g and thermal stability of the resulting films.

Synthesis and properties of silica–polyimide hybrid films derived from colloidal silica particles and polyamic acid

“…The dependence of mechanical properties of PI/SiO 2 on SiO 2 content was observed in other hybrid systems. 9,[23][24][25] The effect of the colloidal SiO 2 size on the mechanical properties of hybrid films was also studied. It can be seen from Tables III and IV, when the content of SiO 2 is fixed (5 or 10 wt %) and SiO 2 particles with different sizes were introduced into PI matrix, there is a maximum value for hybrid films with 10-nm SiO 2 for the modulus and tensile strength, while hybrid films remain the higher elongation at break.…”

Cross-linking of Grafted Copolymer on Colloidal Silica and Introduction of Surface Amino Group

“…The reaction using the alkoxysilane provides a stable covalent boning via the siloxane bond on silica. [8][9][10] The copolymer silane was prepared from MMA and GMA via suspension polymerization in the presence of an initiator (AIBN) and a chain transfer reagent (3-mercaptopropyltrimethoxysilane). In this modification, azeotropical removal of methanol and water produced during the reaction gave an effective attachment of the bound polymer.…”

“…[6][7][8] Chemical modification on the surface of inorganic particles has been employed to improve dispersibility and compatibility in organic solvent, thus providing a processing route that is different from sol-gel process for preparing organic-inorganic hybrid composites. 9,10 Furthermore, when amino, carboxyl or hydroxyl groups got introduced to the surface of inorganic particles, dispersibility of inorganic composite particles, mainly silica, had been greatly increased. 8,11 In this regard, modification methods on the surface of inorganic particle using polymeric silane coupler are convenient and useful.…”

Preparation of Polyimide-Silica Nanocomposites from Nanoscale Colloidal Silica

“…The nanocomposite films are light brown in color, but highly translucent, and levels of translucency are not affected significantly by increasing the silica content. The dispersed phase should be smaller than the wavelengths of visible light to prevent light scattering 31 and a clear film indicates that the size of silica phase was no greater than the wavelengths of the visible lights. It also indicates that the nano-size silica particles are well dispersed in the PI matrix.…”