Highly soluble polyamide-polyhedral oligomeric silsesquioxane hybrid nanocomposites: Synthesis and characterization

A method of preparing linear polyamide-polyhedral oligomeric silsesquioxane (PA-POSS) hybrid nanocomposites in a reactor using thionyl chloride/triethylamine (TEA) as the activating agent was investigated. Soluble polyamic acid (PAA) having carboxylic acid end groups were first synthesized by condensation reaction of 2,2- bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, (6FODA). The PAA was acylated by SOCl2/TEA and followed by the addition of different mole percentages of aminopropyl heptacyclopentyl POSS (AP-POSS) and 3-(trifluoromethyl) aniline to get the PA-POSS hybrid nanocomposites. The chemical structure of PA-POSS hybrid nanocomposites were investigated by ATR-FTIR and NMR spectroscopic techniques. Thermal and morphological properties of PA-POSS were influenced by changing the percentage of POSS and investigated by thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Wide angle X-ray diffraction and contact angle measurements. The PA-POSS with hexafluoroisopropylidene and POSS groups have higher bulk density resulting in higher free volume and then increasing the solubility property. POLYM. COMPOS., 2012. (C) 2012 Society of Plastics Engineers