‘This is the culmination of something we have been working on for ten years, which is understanding how nature generates materials from proteins...’
Researchers from the University of Cambridge, UK, have created a plant-based polymer film which they say could replace single-use plastics in many consumer products. The material was created by replicating the structures found in spider silk by using soy protein isolate. The researchers said that because all proteins are made of polypeptide chains, under the right conditions plant proteins could be made to self-assemble like spider silk. The research has been reported in the journal Nature Communications.
The technique for producing the polymer uses an environmentally friendly mixture of acetic acid and water, combined with ultrasonication and high temperatures to improve the solubility of the soy protein isolate. This method is said to produce protein structures with enhanced inter-molecular interactions guided by the hydrogen bond formation. The second step of the process involves removing the solvent, resulting in a water-insoluble film. The process requires very little energy.
The research team explain that because of the regular arrangement of the polypeptide chains, there is no need for chemical cross-linking, which is frequently used to improve the performance and resistance of biopolymer films. The most commonly used cross-linking agents are non-sustainable and potentially toxic. The new material is said to have a performance equivalent to that of plastics such as low-density polyethylene. In addition the material is home compostable.
The new product will be commercialised by Xampla, a University of Cambridge spin-out company, developing replacements for single-use plastics and microplastics. The company is set to introduce a range of single-use sachets and capsules later this year which can replace the plastic used in products such as dishwasher tablets and laundry detergent capsules.
Professor Toumas Knowles at Cambridge’s Yusuf Hamied Department of Chemistry said: ‘This is the culmination of something we have been working on for ten years, which is understanding how nature generates materials from proteins. We didn’t set out to solve a sustainability challenge. We are motivated by curiosity as to how to create strong materials from weak interactions.