The conversion of castor oil to a series of functional polyamides inspired by natural silks

Abstract

The design of functional polyamides for specialized applications has attracted increasing attention during recent years. Herein, a facile and efficient method towards mechanical strong functional polyamides with varied side groups is developed. An α,ω-diene functional amide monomer was prepared through the amidation reaction of methyl 10-undecenoate (a kind of castor oil derivative) and 1,3-diamino-2-propanol. The pendant hydroxyl group was converted to ester groups to afford six other monomers. High molecular weight functional polyamides with varied pendant groups, including hydroxyl, acetate, butyrate, isobutyrate, benzoate, acrylate, and imidazole, were prepared via thiol-ene addition polymerization. Differential scanning calorimetry (DSC) and atomic force microscopy (AFM) results indicate that the melting temperature, degree of crystallization, and crystalline size depend on the pendant groups. Inspired by natural silk proteins, functional polyamides with controllable mechanical properties can be achieved by copolymerizing of these monomers.