A group of students has developed new manufacturing processes to transform lobster shell waste into biodegradable, recyclable bioplastic. They are studying Innovation Design Engineering, a course delivered jointly by Imperial College London and the Royal College of Art. They have built a series of machines that extract, form and recycle the material, which they believe could be used as a replacement for various single-use plastics.

The project uses chitin, the world’s second most abundant biopolymer, (a naturally produced plastic). Chitin is found in crustaceans, insects, and fungi, but needs to be chemically extracted from the source before it can be turned into the material.

Currently, chitosan, the commercial version of chitin, is expensive to buy and its extraction process is time-consuming. The team, therefore, built a small-scale extractor that enables the initial process of drawing out the chitin from the seafood waste.

The versatility of the material also enabled the designers to achieve different material properties by adjusting the ratios of the base ingredients. This meant they could control the stiffness, flexibility and optical clarity of the material, as well as its thickness.

The group believes that difficulties in forming the material is a key barrier to its widespread adoption by other designers. In order to address this, they built machines that can form the bioplastic using new manufacturing methods tailored to how the material behaves.

The three new manufacturing machines are:

  • Dippy – a heated dip molder comprising of two solid metal elements attached to a heat source, which are dipped in the liquid material and left to dry, forming 3D vessels like cups and containers.
  • Vaccy – a steam heated vacuum former. The bioplastic sheets can be formed into molded packaging, taking on the shape of whatever object is put in the vacuum former.
  • Sheety – an evaporative sheet former that uses heat and wind to transform the bioplastic solution into flat sheets of material. These can then be glued together using the liquid form of the bioplastic.

The material is easily recyclable and can be turned back into the original bioplastic solution. “We believe that this will allow for more experimentation without creating waste,” say the team. At the end of life, it can be poured onto the soil in its liquid form as a natural, non-polluting fertilizer.

To read the full story, visit https://www.imperial.ac.uk/news/191380/imperial-students-find-innovative-lobster-shell/.