SYNTHESIS AND STRUCTURE OF CYCLOLINEAR PO LYORGANOSILOXANES (REVIEW)

Methods of preparation of initial organosiloxanes with different struc ture and methods of preparation of polymers containing such cycles are reviewed. Molecular structure of cyclolinear polyorganosiloxanes with different sizes of cycles, tacticity of polymer chains, and organic s ubstituents is characterized by NMR, hydrodynamic methods, and thermal analysis. The effect of chemical structure of cyclolinear macromolecu les on glass transition, crystallization, melting, and mesomorphism is considered. The important role of cyclic fragment in polymer chain fo r the development of mesomorphic state, which is stable in a wide temp erature range, is demonstrated.