Solvent-free thiol-Ene/-Yne click reactions for the synthesis of alkoxysilyl telechelic poly(propylene oxide)s

• Published in: Reactive & functional polymers 2024-07, Vol.200, p.105939, Article 105939
• Main Authors: Fornaciari, Charlotte, Invernizzi, Fabio, Galbiati, Alessandro, Pasini, Dario
• Format: Article
• Language: English
• Subjects: Alkoxysilyl telechelic poly(propylene oxide)s; Post-polymerization functionalization; Solvent-free approaches; Thiol-ene/−yne click chemistry
• ISSN: 1381-5148
• DOI: 10.1016/j.reactfunctpolym.2024.105939

Thiol-ene/−yne click reactions can be a versatile toolbox for the design and modification of polymers, enhancing functionality and providing opportunities for the development of innovative materials and applications. Here, we report a simple strategy to synthesize alkoxysilyl telechelic poly(propylene oxide)s (PPO)s: a) through a post-polymerization functionalization via Williamson reactions, commercial PPO is modified at the chain-end secondary alcohols with allyl or propargyl units, achieving >99% conversion; b) subsequent click reactions of (3-mercaptopropyl)trimethoxysilane (MPTMS), triggered by thermal and photochemical radical initiators, result in the incorporation of alkoxysilane groups on the polyether chain. Both thermal and photochemical thiol-ene/−yne click pathways are robust methodologies for preparing alkoxysilyl-modified PPOs in excellent yields (> 99%). Optimal conditions were identified as solvent-free, at 65 °C with 2,2′-azobis(2-methylpropionitrile) (AIBN) as the radical source. Detailed NMR analyses confirm the quantitative transformation of vinyl/propargyl functionalities in the resulting alkoxysilyl telechelic PPOs. Preliminary studies on the stability of alkoxysilyl end-groups are reported using 29Si NMR spectroscopy. [Display omitted] •(Multi)functional alkoxysilyl-modified polyethers were prepared and characterized.•Solvent-free thiol-ene/−yne click processes•Quantitative evaluation of the degree of end-functionalization by NMR spectroscopy•The resulting silyl-functionalized polymers showed good stability over time.