Linear semicrystalline polyesters from fatty acids by complete feedstock molecule utilization.

Thermoplastic polymers are currently prepared almost exclusively from fossil feedstocks. In view of the limited availability of such feedstocks, alternative renewable resources are desirable in the long term.[1.2] Polymer production from a renewable resource ideally allows for a complete molecular utilization of the feedstock and carries its molecular structure over into the resulting polymers, providing them with specific desirable properties. In this regard, fatty acids from plant oils are attractive substrates as they contain long-chain linear segments. They also possess two functional groups, as required in principle for the generation of thermoplastics by step-growth polymerization. However, the double bond is located in the center of the molecule. For complete utilization of fatty acids in the generation of crystallizable linear polymers, a functionalization at the chain end is required (Scheme 1). Herein we report the preparation and properties of novel semicrystalline polyesters with long-chain hydrocarbon segments based on complete linear incorporation of oleic acid and erucic acid. carbohydrates by microorganisms or enzymes. Entirely chemical synthetic routes in which the original molecular structure of the utilized plant biomass is substantially retained are an interesting alternative to such biotechnological routes, as they can be efficient in terms of feedstock utilization and reaction space-time yields, and also provide novel properties. Plant oils[5-7] are in principle attractive substrates for semicrystalline long-chain polyesters, as the substrate already provides relatively long (CH2)" crystallizable segments. This is illustrated by preparation of the difunctional monomer sebacic acid from ricinoleic acid,[8] which is converted into aliphatic polyamides such as nylon-6,1O with a beneficially low water uptake. Herein, only one side of the fatty acid chain with respect to the double bond is incorporated into the monomer and ultimately the polymer. For longer-chain aliphatic polyesters, a complete incorporation (Scheme 1) is also of particular importance to achieve sufficient melt and crystallization temperatures for thermoplastic processing and applications. Known aliphatic polyesters based on adipic or higher acids suffer from low melting