Determination of silanol end groups in polysiloxanes obtained from dimethyldichlorosilane hydrolysate (DDSH)

Dimethyldichlorosilane hydrolysate, DDSH, the linear part of which con- tains SiOH end groups, can be used in the preparation of difunctionally terminated (any end groups other than SiOH) polysiloxanes via equilibration polymerisations. In such a case, the problem arises: as to whether the obtained functionalised poly- mers also contain silanol end groups. To the best of our knowledge, the only direct and the most precise analytical procedure to clarify this question is the Karl Fischer titration/determination of SiOH groups. This determination was performed on a model system consisting of trimethylsilyl terminated polysiloxanes, and it was shown that the obtained polymers contained no SiOH groups.