Diversely substituted polyamide structures through thiol ene polymerization of renewable thiolactone building blocks

A thiolactone derivative of 10-undecenoic acid was used as a renewable AB' monomer for the one-pot synthesis of diversely substituted polyamide structures, containing amide moieties both in the polymer backbones and in their side chains. Nucleophilic aminolysis of the thiolactone entity liberates a thiol, which further reacts in a stepwise thiol-ene photopolymerization reaction. Using different primary amines, several structurally diverse polyamides, with physical properties dependent on the length and chemical identity of the side chain, were obtained. Postpolymerization oxidation of the sulfide linkages in the polymer backbone to their corresponding sulfoxides and sulfones altered the material, with the degree of oxidation having an impact on the final mechanical properties. Furthermore, this mild and straightforward polymerization procedure was applied for the synthesis of functional polymer networks

Cyclic Guanidines as Efficient Organocatalysts for the Synthesis of Polyurethanes

A systematic survey of basic/nucleophilic organocatalysts for the polyaddition in bulk of polyols, PEG-600, and PTMO-650, to isophorone diisocyanate (IPDI) has been performed. Guanidines were shown to be very efficient catalysts for the urethane linkage formation. Bicyclic penta-alkylated guanidines such as MTBD led to polyurethane molecular weight and dispersity that are in the range of those observed with tin-based catalysts such as DBTDL. Tetra-alkylated guanidine such as TBD was shown to be a weaker catalyst as compared to pentaalkylated guanidines, as a result of its high reactivity toward isocyanate, resulting in the formation of a less nucleophilic urea. Although the mechanism has not yet been firmly established, these experiments suggest that a nucleophilic-catalysis mechanism, involving the attack of one of the nitrogen of the guanidine onto the unsaturated system of the isocyanate, should not be totally ruled out with such strong Bronsted base catalysts