Researchers Produce Plastic Using Sugar and Carbon Dioxide

Researchers from the Centre for Sustainable Chemical Technologies (CSCT) at the University of Bath have made it possible for some biodegradable plastics to be made using sugar and carbon dioxide in the future, replacing unsustainable plastics, which are made from crude oil.

Safer form of polycarbonate plastic

• Polycarbonate is used to make lenses for glasses, drinks bottles and in scratch-resistant coatings for CDs, phones and DVDs
• Existing manufacture processes for polycarbonate use BPA (banned from use in baby bottles) and highly poisonous phosgene, used as a chemical weapon in World War I
• Bath Researchers have formed alternative polycarbonates using sugars and carbon dioxide in a new process that also uses low pressures and room temperature, making it economical and safer to produce
• This new type of polycarbonate can be biodegraded back into carbon dioxide and sugar with the help of enzymes from soil bacteria
• This new plastic is bio-compatible, therefore could be used for medical implants or as scaffolds for growing emergency organs for transplant in the future.

Polycarbonates from sugars offer a better sustainable alternative to traditional polycarbonate from BPA; however the process uses an extremely toxic chemical called phosgene. Researchers at Bath have developed a much safer, even more sustainable substitute which adds carbon dioxide to the sugar at room temperature and at low pressures.

Biodegradable and bio-compatible

The resulting plastic has similar physical properties to those made from petrochemicals, being strong, scratch-resistant and transparent. The main difference is that they can be degraded back into carbon dioxide and sugar with the help of the enzymes found in soil bacteria.

The new BPA-free plastic could potentially substitute existing polycarbonates in items such as food containers and baby bottles, and as the plastic is bio-compatible, it could also be used as scaffolds for growing tissues or organs for transplant, or for medical implants.

With an ever-growing population, there is an increasing demand for plastics. This new plastic is a renewable alternative to fossil-fuel based polymers, potentially inexpensive, and, because it is biodegradable, will not contribute to growing ocean and landfill waste. Our process uses carbon dioxide instead of the highly toxic chemical phosgene, and produces a plastic that is free from BPA, so not only is the plastic safer, but the manufacture process is cleaner too.

Dr Antoine Buchard, Whorrod Research Fellow, The University’s Department of Chemistry

Using nature for inspiration

Dr Buchard and his team at the Centre for Sustainable Chemical Technologies published their research in a series of articles in the journals Polymer Chemistry and Macromolecules.

Specifically, they drew inspiration from nature for the process, using the sugar found in DNA known as thymidine as a building block to make a unique polycarbonate plastic with huge potential.

Thymidine is one of the units that makes up DNA. Because it is already present in the body, it means this plastic will be bio-compatible and can be used safely for tissue engineering applications.

Georgina Gregory, PhD Student and First Author of the articles

“The properties of this new plastic can be fine-tuned by tweaking the chemical structure – for example we can make the plastic positively charged so that cells can stick to it, making it useful as a scaffold for tissue engineering.” Such tissue engineering work is already underway in partnership with Dr Ram Sharma from Chemical Engineering, also part of the CSCT.

Using sugars as renewable alternatives to petrochemicals

The Researchers have also considered using other sugars such as mannose and ribose.

Chemists have 100 years’ experience with using petrochemicals as a raw material so we need to start again using renewable feedstocks like sugars as a base for synthetic but sustainable materials. It’s early days, but the future looks promising.

Dr Antoine Buchard, Whorrod Research Fellow, The University’s Department of Chemistry

This research was supported by Roger and Sue Whorrod (Fellowship to Dr Buchard), EPSRC (Centre for Doctoral Training in Sustainable Chemical Technologies), and a Royal Society research Grant.