UV‐activated silicone oligomer cross‐linking through photoacid and photobase organocatalysts

Abstract

Diphenyl iodonium hexafluorophosphate salt and N‐alkyl morpholino acetophenone were shown to be effective photocatalyst generators for the cross‐linking of α,ω‐silanol terminated silicone oligomers. These two photoacid and photobase‐induced polycondensation pathways provided an attractive and efficient alternative to toxic and expensive organometallic catalysts. The utility of this novel UV‐curing process was demonstrated with a combination of time‐resolved infrared spectroscopy to follow the fast reaction kinetics and solid‐state 29Si nuclear magnetic resonance to investigate the polysiloxane network. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39875.

The Current State of Silicone-Based Dielectric Elastomer Transducers

“…In addition, the choice of curing chemistry also provides some limitations, such as to the commonly applied hydrosilylation curing reaction, which can be inhibited by the presence of nitrogen‐ and sulphur‐containing substituents. For functional silicone systems it can therefore be convenient to change the curing chemistry to, for example, condensation curing or UV curing, in order to enable the further functionalisation of silicone elastomers.…”

Synthesis of carbamates from carbon dioxide promoted by organostannanes and alkoxysilanes

“…The challenge is the transfer of two methoxy moieties to generate catalytic amounts of dialkyltin dialkoxide. Alkoxysilanes are versatile reagents industrially used for coatings, construction, zeolite preparation, semiconductors and silicon polymers (polydimethylsiloxane, polydimethoxysiloxane) . Orthosilicates are obtained by reacting tetrachlorosilanes with alcohols.…”

UV‐Cured, Platinum‐Free, Soft Poly(dimethylsiloxane) Networks

“…The major drawbacks of platinum‐catalyzed cross‐linking of silicones are the highly priced noble metal catalyst used in the cross‐linking reaction as well as poisoning of the catalyst by compounds containing nitrogen, sulfur, phosphorus, and tin. Studies have been done extensively on UV curing of acrylic silicones7 or classical condensation curing by UV light,8 but very few examples on vinyl‐terminated silicones are available in the literature 9. Previously prepared UV‐curable PDMS systems rely on low‐molecular‐weight linear PDMS, which results in heavily cross‐linked hard networks 9b,c.…”