The ubiquitous nature of starch makes it a tantalising basis of sustainable plastic manufacture. Extensive hydrogen bonding between chains, however, makes the plasticisation of starch difficult but this work shows that the incorporation of a simple quaternary ammonium salt can lead to a flexible plastic with mechanical properties similar to oil derived plastics. Compression-moulding produces a transparent material with mechanical strength which is similar to some polyolefin plastics. It is shown that the material can be extruded and/or compression-moulded and these processes improve further the mechanical strength of the samples. Most importantly, it is shown that these plastics are recyclable and ultimately compostable.

The solid-state structure of the title compound, C19H15NS2, is unusual among substituted thiophene/pyrrole derivatives in that the molecular packing is dominated by pi-pi interactions between the benzyl substituents. This may be due to the large torsion angles observed between adjacent heterocycles. Torsion angles between adjacent rings in polypyrrole and polythiophene conducting polymers are related to conjugation length and the conductivity properties of the polymer materials. The title compound crystallizes in space group P21/c with two molecules in the asymmetric unit, both of which exhibit disorder in one of their thiophene rings.