(517a) Invited Talk: Thermoplastic Elastomers and Thermosets Derived From Vegetable Oils

A great challenge to overcome is the replacement of traditional petroleum-based polymers with materials derived from sustainable, alternative resources. Vegetable oils are an attractive substitute for petroleum sources for the derivation of polymers, due to their abundance, low cost, and lack of toxicity. We are developing two classes of polymers derived from vegetable oils: thermoplastic elastomers and thermosets.

Of particular interest is the design of nanostructured polymers from sustainable sources with well-defined molecular characteristics and competitive properties to petroleum-derived materials. We are developing triblock copolymers with hard, glassy outer blocks and a soft, rubbery midblock which can act as thermoplastic elastomers and pressure sensitive adhesives. We have utilized reversible addition fragmentation chain transfer polymerization for polymerizing fatty acrylates, for the production of triblock copolymers. The thermal and mechanical properties of the polymers are readily tuned by varying the composition of fatty acids used as the raw material source for the polymers.

Epoxy resins have been synthesized containing epoxidized soybean oil (ESO) and traditional petroleum-derived epoxy resin components (the diglycidyl ether of bisphenol A, DGEBA, and methylene dianiline). Significantly higher curing temperatures are required for ESO as compared to DGEBA. Increasing the concentration of ESO in the resin significantly decreased the glass transition temperature. However, epoxy resins with high ESO content (60-100 wt% relative to the total epoxide-bearing molecules in the mixture) exhibited a second, higher temperature peak in the derivative of the thermogravimetric analysis weight loss curve. Significant differences were observed in the hydrolytic degradation characteristics of the polymers at 80 °C in sodium hydroxide (NaOH) solutions. The presence of degradable cleavage points throughout the network structure may provide a valuable route for recycling these materials after their useful lifetime.