Degradable, silyl ether thiol–ene networks

Abstract

The polymerization of silyl ether containing thiols and alkenes results in tunable, degradable thermosets with potential in implantable electronics.

Degradable epoxy resins based on bisphenol A diglycidyl ether and silyl ether amine curing agents

“…The T g s from XL 1 and XL 2 are comparable to the T g s of most epoxy networks of bisphenol A diglycidyl ether cured with conventional aliphatic amines, while the T g s for XL 3 and XL 4 are lower. The observed T g s from both DSC and DMA measurements were higher than those reported for polyurethane biodegradable networks obtained from epoxy amine reactions, and suggest that these networks could be utilized in applications requiring degradable polymers with higher T g s …”

“…The presence of hydrolyzable SiO bonds in the curing agents affords degradable characteristics . The curing agents were selected so that the degradation rate could be controlled by the number of SiO bonds and the extent of crosslink density estimated from the NH‐functionality .…”

“…The networks contained labile ester bonds, and degradation rates were controlled by mixing different mass ratios of epoxy terminated polyurethanes. This study demonstrated the possibility of making tunable biodegradable networks through epoxy amine reactions; however, the negative T g values reported for the networks with high degradability could be limiting in some applications . Silyl ethers, (RO) n SiR' 4‐ n , and silyl esters, (RCOO) n SiR' 4‐ n , are hydrolytically labile groups that have been exploited in the literature.…”

“…Controllable degradation rates varying from hours to months were reported by changing the substituent on the silicon atom in polymers obtained from bifunctional silyl ether crosslinkers . In addition, silyl ether biodegradable polymers have successfully been applied as a support for flexible electronic device fabrication without any significant swelling and any changes in the electrochemical performance of a fabricated gold electrode …”

Zinc‐Catalyzed Hydrosilylation Copolymerization of Aromatic Dialdehydes with Diphenylsilane

“…Poly(silyl ether)s containing SiOC bonds in their main chains are thermostable and have long been a commercial interest as degradable plastic, matrix for controlled release of drugs and membrane materials . However, partly due to sensitivity of the SiOC bond under acidic or basic conditions,[11c,14] poly(silyl ether)s are usually synthesized through the cross‐dehydro coupling of α,ω‐diols with dihydrosilanes or the hydrosilylation of α,ω‐dicarbonyl compounds (aldehydes and ketones) with dihydrosilane by the traditional ruthenium[16a,17] and rhodium[16b,c] based catalytic systems. The mechanism proposed by Ojima et al in 1975 is shown as Scheme , which reveals that the catalysts based on ruthenium and rhodium transition metals experience the redox process to afford the driving force for the SiH bond cleavage and its insertion into CO double bond, an “insertion‐propagation” process.…”