The high chain flexibility, chemical robustness, low surface tension, high moisture resistance and low toxicity etc… are some of the reasons why poly(dimethylsiloxane) (PDMS) derivatives have been used for more than 60 years as high performance elastomers in numerous and various applications (e.g. in biomaterials, personal care products, semi-conductor devices and so on). However, to meet new requirements and broaden the domains of application of such polymers, it is important to develop synthetic strategies that allow the introduction of novel functionalities without, if possible, the use of metal-based catalysts. In this context, we have been interested in applying Aza-Michael addition reaction to PDMS-polymers: this reaction impliesan amine as nucleophile and an electron-deficient alkene as acceptor, and may benefit from mild conditions (no metallic catalyst, no solvent, low T) and allows high yields with no by-product. Yet controlling perfectly the reaction remains an issue; indeed a primary amine can undergo two successive additions, such that a mixture of (1°, 2° and 3°) amines may result if the reaction is not well controlled (Figure 1). This communication deals with the understanding of the aza-Michael addition involving primary amine containing PDMS and various acceptors. For such purpose, the impact of operating conditions (such as T, organo-catalysts, type and amount of solvent) on the kinetics and the selectivity control on a model system will be presented. In particular, our attempts to obtain 100% mono-adduct (2°amine) or 100% di-adduct (3° amine) in a reasonable timescale will be discussed. The extension of the optimized conditions to various systems that differ in the donor molecular weight or structure (α,ω-telechelic or graft PDMS, amine content) or different acceptors demonstrates the robustness of such technology to synthesize polymers with controlled structures and novel properties.

Aza-Michael reaction applied to PDMS: Kinetic modelling, selectivity control and novel potentialities

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.