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In Aerogels, nanoparticles are connected together to form loosely connected network, leaving very high fraction of empty space (or porosity). Due to this high porosity, aerogels have exceptional properties such as low density, low dielectric constant and low thermal conductivity. Traditional Silica Aerogels, however, have limited use as thermal insulation material because of its cost. The present study is aimed at investigation of mechanical properties such as Tensile Strength, Stiffness and Compressive Strength of Aluminium Hydroxide / Epoxy composite filled with Silica Aerogel material. The Thermal Conductivity is also evaluated experimentally. As per ASTM standards, the test specimen's preparation and testing is carried out, and results are presented.

Embedding rare earth compounds and inorganic materials in polymer matrix are of great interest due to its various applications in sensors, optical batteries etc. The hydrated form of optical compounds possesses interest due to the possibility of crystal field effect on the electronic and magnetic field structure of the 4f shell. The stiochiometric cerium compounds have attracted attention due to its high temperature phase stability, high melting point, low thermal conductivity, optical fluorescence etc. In this paper we discuss the synthesis of cerrous sulphate Ce2(SO4)3, Cerium fluoride CeF3and Cerium Phosphate doped with terbium Ce1-xPO4:Tbxcomposites and dependence of their structural and optical behavior on particle size. Cerrous sulphate exists in several phases, mostly hydrated. In polymer composite the anhydrous phase of Ce2(SO4)3is observed. Also CePO4composites crystallize to monazite phase. The significant changes in Ce3+emission and absorption spectra are observed due to this phase change. Cerium fluoride composites prepared with different concentration show three absorption peaks around 237, 275 and 265nm. The lower concentration of CeF3shows different absorption. CePO4composites doped with various concentrations of terbium shows intense green emission at 543 nm and maximum energy transfer for 10 mol % of Tb3+. The Ce3+emission is shifted to 337nm. The S.E.M. photograph of the composite shows well separated particles with average size 300nm.