METHOD OF SYNTHESIS OF CYCLOLINEAR SILOXANE BLOCK-COPOLYMERS Russian patent published in 1998 - IPC

FIELD: organic chemistry and technology. SUBSTANCE: phenyltrichlorosilane solution is mixed with α,ω-dihydroxyoli- -gomethylsiloxane at polymerization degree 50-150 or 210-250 and stirred for 1.5 h under pressure by 10-20% lower of atmospheric one and process is terminated at 110-125 C. Process is carried out in the presence of saturated solution of K₂CO₃ at ratio K₂CO₃/LiCl = 1.15-1.25 and nonionogenic surface-active compound α,ω-dihydroxyoligoorganosiloxane at polymerization degree 5-10 up to formation of a substance of the formula: where n = 5-150 or 210-250. Substance properties: strength limit at rupture is 6.5-12.0 MPa, relative elongation is 216-334%, residual elongation is 3-8%. EFFECT: improved chemical-technological and physical-mechanical parameters of the end product. 1 tbl