The present work addresses the synthesis of 1,4-bis(2-(4-hydroxyphenyl)-2-propyl)benzene based cyanate ester-silica hybrid (CE-SiO 2 ) nanomaterials by an in situ sol-gel method. The nanomaterials are synthesized using a 1,4-bis(2-(4-cyanotophenyl)-2-propyl)benzene [CE] (organic phase) monomer and tetraethoxysilane (TEOS) (inorganic phase) in the presence of various molar ratios of coupling agents [c-aminopropyltriethoxysilane (APTES) or 3-glycidoxypropyltrimethoxysilane (GPTMS)] through covalent bond interaction.The formation of a covalent bond between the organic and inorganic phases is confirmed by FT-IR.Thermal studies indicate that nanomaterials (CE-SiO 2 ) show a higher T g and thermal degradation temperature when compared with neat CE. Morphological studies confirm the molecular level dispersion of silica and CE resin. From the contact angle measurement, the hybrid materials are seen to possess better hydrophobicity i.e. the contact angle value increases from 89u and 57u to 108u and 78u for water and diiodomethane as a probe liquid respectively, also surface free energy reduced from 32.8 to 19.00 mJ m 22 . These materials are expected to find wide application in the field of microelectronics and optoelectronics.

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Polyhedral oligomeric silsesquioxane (POSS) -polyimide (PI) hybrid nanocomposites were prepared by a two-step approach, bisphenol-A ether diamine (BAED) and pyromelletic dianhydride (PMDA) in 1-methyl-2-pyrrolidone (NMP) were used to prepare polyamic acid (PAA) to which varying weight percentages of OAPS in NMP were added. During the second step, the polycondensation was effected by thermal imidization. The formation of hybrid nanocomposites was confirmed by using FTIR spectra. The thermal properties of POSS-PI nanocomposites were studied using differential scanning calorimetry and thermogravimetric analysis. The lowest dielectric constant 2.68 was achieved for 15 wt.% POSS-PI material when compared with the value of 3.34 for the neat PI. Data from thermal studies indicate that the incorporation of POSS into polyimide significantly enhanced the glass transition temperature (T g ), thermal stability, char yield and flame-retardant properties of hybrid nanocomposites than that of neat PI. The excellent combination of both dielectric and thermal properties of the material developed in the present study will find application in microelectronics.

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