ABSTRACT:The reaction of heterofunctional condensation of 1,1-dichloro-1-sila-2-oxadihydrophenanthrene with dihydroxydiphenylsilane at various ratios of initial compounds in the presence of pyridine is investigated. ␣,-Dihydroxysilaoxadihydrophenanthrene-diphenylsiloxane oligomers with various degrees of condensation are obtained. Organosiloxane block copolymers with the regular arrangement of silaoxadihydrophenanthrene-diphenylsiloxanes fragments in the main linear dimethylsiloxane chain are produced by the reaction of heterofunctional condensation of ␣,-dihydroxysilaoxadihydrophenanthrene-diphenylsiloxanes with ␣,-dichlorodimethylsiloxanes in the presence of anhydrous pyridine, as an acceptor of hydrochloric acid. Thermogravimetry, differential scanning calorimetry, gel permeation chromatography, and wide-angle X-ray analysis are carried out on the synthesized block copolymers. The microheterogeneous structure of block copolymers is observed at definite values of the length of the flexible dimethylsiloxane chain by DSC and X-ray investigation.

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ABSTRACT:The heterofunctional condensation of 1,3-dichloro-1,3-disila-1,3-diphenyl-2-oxaindane with dihydroxydiphenylsilane at various ratios of initial compounds in the presence of amines was carried out, and ␣,-dihydroxy(1,3-disila-1,3-diphenyl-2-oxaindane)-diphenylsiloxane oligomers with various degrees of condensation were obtained. Corresponding block copolymers were obtained by heterofunctional polycondensation of synthesized ␣,-dihydroxy(1,3-disila-1,3-diphenyl-2-oxaindane)-diphenylsiloxane oligomers with ␣,-dichlorodimethylsiloxanes in the presence of amines. Thermogravimetry, gel permeation chromatography, differential scanning calorimetry, and wide-angle X-ray analysis were carried out on the synthesized block coplymers. Differential scanning calorimetry and wide-angle X-ray studies of these copolymers showed that their properties were determined by the ratio of the lengths of the flexible linear poly(dimethylsiloxane) and rigid poly(1,3-disila-1,3-diphenyl-2-oxaindane)-diphenylsiloxane fragments in the main macromolecular chain. Two-phase systems were obtained with specific flexible and rigid fragment length values in synthesized block copolymers.