Polysiloxanes, ladder

Table 2. Length of the Kuhn segment A and chain diameter d for ladder polysiloxanes according to the data of sedimentation-diffusion studies and viscometry... 

Fig. 4. Sedimentation coefficient (s) vs. molecular weight M - for ladder polysiloxanes 1 poly-phenylsiloxane in benzene ) 2 poly(phenyl-isohexylsiloxane) (1 1) in butyl acetate ...

Fig. 20. Shear optical coefficient in]/i il as a function of molecular weight M for solutions of various samples of ladder polysiloxanes. Numbers on curves correspond to those in Table 5...

The points in Fig. 24 represent the experimental values of A for a ladder poly-dichlorophenylsfloxane and cellulose carbanilate For both polymers the experimental data are in agreement with theoretical Curve 4 corresponding to the value of d/A = 0.5 for a kinetically flexible chain polymer. This qualitatively demonstrates that the hydrodynamic properties of the molecules of these two polymers at low X differ from those of an infinitely thin worm-like model. However, to obtain quantitative agreement between theory and experimental data according to Curve 4 in Fig. 24, A/d should be equal to 2 — a reasonable value for many flexible-chain polymers not realistic for such r d-chain polymers as ladder polysiloxanes or cellulose ethers and esters. 

Optical Anisotropy and Structui% of Polymer Chains Ladder Polysiloxanes and Cellulose Esters and Ethers... 

Table 5. Limiting values of (nj/lnl and anisotropy of the segment oj - 2 the monomer unit ay - of ladder polysiloxanes... 

As already indicated, (p. 170) the dispersion of the Kerr effect in the range of radio frequencies is a characteristic property of rigid-chain polymer solutions. This can be seen in Figs. 59-61 which show frequency dependences of EB for solutions of polj chlorohexyl isocyanate)s, cellulose earbanilate and ladder polychlorophenylsiloxane. Similar dependences have been obtained for poly(butyl isocyanate) various cellulose ethers and esters and ladder polysiloxanes ... 

Fig. 6 Difference between ladder polysilsesquioxanes and ladder polysiloxanes...

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