The highly crystalline and pure RUT (RUB-10) zeolite could be obtained from the hydrothermal conversion of FAU zeolite used as a crystalline Si/Al source in tetramethylammonium hydroxide (TMAOH) media. As compared to amorphous silica/Al(OH) 3 and amorphous silica/γ-Al 2 O 3 sources, the crystallization rate for the formation of RUT zeolite was clearly faster when FAU zeolite was employed as the Si/Al source. Moreover, it was found that the hydrothermal conversion of FAU zeolite into RUT zeolite depended significantly upon the Si/Al ratio of the starting FAU zeolite.FAU zeolite could be hydrothermally converted into the highly crystalline and pure RUT zeolite under the following molar ratios: Si/Al = 17-28, TMAOH/SiO 2 = 0.2 and H 2 O/SiO 2 = 3-7.
We investigate the effects of laser irradiation on the optical properties of ZnO nanoparticles in an organic solvent. ZnO nanoparticles are synthesized using normal precipitation methods in 2-propanol. Irradiating the nanoparticles in the solvent with unreacted reactants, which is colloidal solution without purification after the preparation, results in a reduction in the green luminescence, which is related to the number of surface oxygen defects, and an increase in the ultraviolet luminescence, which is related to the crystallinity of ZnO. Irradiation does not, however, significantly alter the nanoparticle diameter. Conversely, irradiation of purified (reactant-free) ZnO nanoparticles in the solvent does not change the ZnO photoluminescence intensity. We conclude that laser irradiation of the ZnO nanoparticles dispesed with reactants reduces the number of surface defects on the ZnO nanoparticles. Without the reactants, laser
Polyimide (PI) was successfully hybridized with silica and PDMS by synchronizing two reactions; imidization of poly(amide acid) (PAA) and sol-gel reaction of tetraethoxysilane (TEOS) and diethoxydimethylsilane (DEDMS). TEOS and DEDMS were used as precursors for the formation of silica and polydimethylsiloxane (PDMS), respectively. The progress of sol-gel reaction was confirmed by IR. It was revealed from the study of scanning electron microscopy that silica has better compatibility than PDMS. The effect of the silica and PDMS on the mechanical and thermal properties of the hybrids was studied. Hybrid containing 3-5 wt% of silica and 3-5 wt% of PDMS gave the highest tensile properties. Dynamic viscoelastic analyses and thermogravimetric analyses revealed that thermal properties were improved by the hybridization.
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