Low dielectric polybenzoxazine nanocomposites (SBA-15/PBZ) containing mesoporous silica (SBA-15) were successfully synthesized, using benzoxazine functionalized SBA-15 (BZ/SBA-15) and benzoxazine monomer, through thermal ring opening polymerization. SBA-15 was functionalized with benzoxazine functional silane via grafting method. The benzoxazine functionality in BZ/SBA-15 was confirmed by FT-IR, 13 C CPMAS, 29 Si CPMAS NMR, XPS, TGA and nitrogen porosimetry analysis. By increasing the amount of BZ/SBA-15, the SBA-15/PBZ nanocomposites possess higher T g and good thermal stability. 7.5 Wt % of BZ/SBA-15 reinforced polybenzoxazine nanocomposite possesses an ultra-low dielectric constant of 1.75 at 1 MHz.

Measurement of nematic liquid crystal splay elastic constants by disclination line motion in high pretilt, negative dielectric anisotropy pi-cells

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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.