• Polymer(Korea)
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• v.27 no.2
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• pp.135-141
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• 2003

A series of organophilic montmorillonites (MMTs) modified with various alkyl siloxane amino oligomer groups have been synthesized and their properties were investigated. New organophilic MMTs containing siloxane amino oligomers with alkyl group instead of conventional alkyl amines were synthesized to improve thermal stability as well as gallery spacing. The organophilic MMTs were synthesized from MMT by utilizing the siloxane amino oligomers with various alkyl groups in the water/dioxane solution, which was performed without aq. HCl. Thermal decomposition temperature, gallery spacing, and hydrophobicity of synthesized organophilic MMTs were investigated. X-ray diffraction and TEM experiment results on new organophilic MMTs demonstrated that introduction of siloxane amine oligomers increased d-spacing between silicate layers. The decomposition temperatures of new organophilic MMTs measured by TGA was remarkably improved above 200℃ as compared with those of conventional alkyl substituted organophilic MMTs.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.490-495
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• 1996

Low molecular weight linear chlorine terminated siloxanes (yields;71.2~86.5%) were prepared by reactions of cyclotri-, cyclotetra- and cyclopentasiloxane with dimethyldichlorosilane in the presence of pyridine N-oxide catalyst. The amine terminated siloxane oligomers were obtained in good yields(76.2~85.3%) by the reaction of linear chlorine terminated siloxanes with dimethylamine at $0^{\circ}C$. In this investigation, we have studied on the syntheses and properties of copolymers (yields;58.0~71.0%) obtained from the reaction of amine terminated siloxane oligomers with 1,4-bis(dimethylhydroxysilyl)benzene. The structures and properties of the copolymers were examined by FT-IR, $^1H$-NMR, TGA and DSC. Initial degradation temperatures($T_D{^i}$) of the polymer I and IV were confirmed as 476 and $485^{\circ}C$, respectively. The thermal stabilities of the polymers were found to be increased with increasing n of $(R_2SiO)_n$. The glass transition temperatures(Tg) of the polymers were increased with decreasing n of $(R_2SiO)_n$, and the lowest Tg revealed $-76^{\circ}C$ when n=5.