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- Title
When Attempting Chain Extension, Even Without Solvent, It Is Not Possible to Avoid Chojnowski Metathesis Giving D 3.
- Authors
Liao, Mengchen; Chen, Yang; Brook, Michael A.; Rubinsztajn, Sławomir; Cypry, Marek; Stanczyk, Wlodzimierz
- Abstract
A simple, mild and efficient method to prepare HSi- or HOSi-telechelic, high-molecular-weight polydimethylsiloxane polymers (to 41,600 g·mol−1) using the one-shot hydrolysis of MHMH is reported; titration of the water allowed for higher molecular weights (to 153,900 g·mol−1). The "living" character of the chain extension processes was demonstrated by adding a small portion of MHMH and B(C6F5)3 (BCF) to a first formed polymer, which led to a ~2-fold, second growth in molecular weight. The heterogeneous reaction reached completion in less than 30 min, much less in some cases, regardless of whether it was performed neat or 50 wt% in dry toluene; homogeneous reactions in toluene were much slower. The process does not involve traditional redistribution, as judged by the low quantities (<3%) of D4 produced. However, it is not possible to avoid Chojnowski metathesis from MHDDMH giving D3, which occurs competitively with chain extension.
- Subjects
MOLECULAR weights; SOLVENTS; LIVING polymerization; POLYDIMETHYLSILOXANE; POLYMERS
- Publication
Molecules, 2021, Vol 26, Issue 1, p231
- ISSN
1420-3049
- Publication type
Article
- DOI
10.3390/molecules26010231