Salt modified starch: sustainable, recyclable plastics

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.