Pendant Chain Effect on the Synthesis, Characterization, and Structure-Property Relations of Poly(di-n-alkyl itaconate-co-isoprene) Biobased Elastomers

A series of biobased elastomers, poly(di-n-alkyl itaconate-co-isoprene)s (PDAIIs), were prepared by using itaconic acid as a renewable starting material. It is revealed that pendent chain profoundly affected the structure and properties of PDAIIs. The molecular structures of the PDAIIs were analyzed by ¹H NMR and FTIR. Dialkyl itaconate to isoprene reactivity ratios measured by Kelen-Tüdös method demonstrated that PDAIIs with short side chains tended to alternate copolymerized and the long side chain ones tented to gradient copolymerized. Glass transition temperature, dielectric properties, and thermal stability of the PDAIIs were studied and these properties were tunable by varying the side chain length. Tensile tests revealed that cross-linked PDAIIs are elastic with a high elongation at break. With renewable resources and the side chain adjustability, PDAII elastomers potentially have a positive economic and ecological impact.