Saeed, S. and Khalil, M. and Ahmad, Z. (2009) Polyimide-silica Hybrids: Structural and Morphological Investigations. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY, 46 (2). pp. 152-162. ISSN 1060-1325
Full text is not hosted in this archive but may be available via the Official URL, or by requesting a copy from the corresponding author.
Official URL: http://www.informaworld.com/smpp/content~db=all?co...
Polyimide (PI) containing pendant hydroxyl functional groups have been employed for preparation of PI-silica hybrids through the sol-gel process. A stoichiometric amount of pyromellitic dianhydride (PMDA) was reacted with a mixture of oxydianiline (ODA) and 3,3'-diamino-4,4'-dihydroxybiphenyl (DAHP) in dimethylacetamide (DMAc) solvent to prepare the precursor poly(amic acid) (PAA) solution for the PI. Various proportions of tetraethoxysilane (TEOS) were mixed with PAA to prepare PI-silica hybrids through sol-gel process. The structure and morphology of these hybrids were investigated with field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), optical surface profilometery, and Fourier transform infrared (FTIR) spectroscopy and compared with the one in which the matrix was prepared from PMDA and ODA with no pendant hydroxyl functionalities. Formation of silica lean and silica rich phases (SLP and SRP) as a result of formation of nano-sized silica clusters with diffused boundaries, dispersed in the matrix and their agglomerates, respectively, along with totally different morphology suggest a strong influence of hydroxyl groups in controlling the morphology of PI-silica hybrids. A model namely Retain and React has been introduced to explain observed structure.
|Subjects:||Physical Science > Nanophysics|
Physical Science > Nano objects
Material Science > Nanochemistry
Material Science > Nanostructured materials
|Divisions:||Faculty of Engineering, Science and Mathematics > School of Physics|
Faculty of Engineering, Science and Mathematics > School of Chemistry
|Deposited On:||16 Nov 2009 09:39|
|Last Modified:||16 Nov 2009 09:39|
Repository Staff Only: item control page