We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Oligo‐Condensation Reactions of Silanediols with Conservation of Solid‐State‐Structural Features.
- Authors
Kannengießer, Jan‐Falk; Morgenstern, Bernd; Janka, Oliver; Kickelbick, Guido
- Abstract
Oligo‐ and polysiloxanes are usually prepared by condensation reactions in solvents without control of stereochemistry. Here we present a solventless thermal condensation of stable organosilanols. We investigated the condensation reactions of organosilanediols with different organic substituents, having in common at least one aromatic group. The condensation kinetics of the precursors observed by NMR spectroscopy revealed a strong dependence on temperature, time, and substitution pattern at the silicon atom. SEC measurements showed that chain length increases with increasing condensation temperature and time and lower steric demand of the substituents, which also influences the glass transition temperatures (Tg) of the resulting oligo‐ or polymers. X‐ray diffraction studies of the crystalline silanediols and their condensation products revealed a structural correlation between the substituent location in the crystalline precursors and the formed macromolecules induced by the hydrogen bonding pattern. In certain cases, it is possible to carry out topotactic polymerization in the solid‐state, which has its origin in the crystal structure.
- Subjects
POLYMERS; GLASS transition temperature; STEREOCHEMISTRY; CONDENSATION reactions; NUCLEAR magnetic resonance spectroscopy; HYDROGEN bonding
- Publication
Chemistry - A European Journal, 2024, Vol 30, Issue 16, p1
- ISSN
0947-6539
- Publication type
Article
- DOI
10.1002/chem.202303343