Hydrogenated cyclic and linear PDMS

The work summarized in Table 26.1 has been conducted for isolated rings in dilute solution, either at theta conditions or in good solvents. Recent small-angle neutron-scattering studies on bulk rings have shown that they adopt conformations more compact than those in solution (Arrighi et al, 2004). The polymers examined were hydrogenous and deuterated linear and cyclic PDMS. For linear PDMS, Rg oc For cyclic PDMS, Rg oc thus, R c) ... 

To try and confirm foe presence of any linear hydroxyl- terminated deuterated siloxanes, which are not easily resolved from the cyclic siloxanes by GLC, foe technique of GC/CI-MS was applied to the sample. This technique has been reported to clearly show foe presence of hydroxyl end-groups in the analogous hydrogenated PDMS [70]. 

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