Single-use plastics are common pollutants that end up in the oceans and landfills all around the world. A group of researchers from the University of Cambridge has created a polymer film that mimics the properties of spider silk, which is one of the strongest materials in nature. The creation is plant-based, sustainable, and scalable and could replace single-use plastics in many consumer products.
The material is created using a new method for assembling plant proteins in the materials mimicking silk on a molecular level. Production is energy-efficient and uses sustainable ingredients to create a plastic-like free-standing film that can be produced at an industrial scale. Researchers can also add non-fading structural color to the polymer, and it can be used to make water-resistant coatings.
One of the most important aspects of the new material is that it’s home compostable. Other types of bioplastics require commercial composting facilities to degrade. The material also requires no chemical modifications to its natural building blocks allowing it to safely degrade in most natural environments. The product will be commercialized by Xampla, a spin-out company from the University of Cambridge developing replacements for single-use and micro-plastics.
The company will introduce various single-use sachets and capsules later this year that can replace plastics used in everyday products like dishwasher tablets and laundry detergent capsules. During the research, the scientists were interested in why materials like spider silk are strong despite having weak molecular bonds. They found that one of the key features giving spider silk the strength it’s renowned for is that the hydrogen bonds are arranged in regularly spaced intervals and at a high density.
Scientists also note that a replacement for plastic requires another polymer, and in this case, they used soy protein isolate. The material is readily available as a byproduct of soybean oil production. Their technique uses an environmentally friendly mixture of acetic acid and water combined with ultrasonication and high temperatures to improve the solubility of soy protein isolate. The resulting material has performance equivalent to engineered plastics like low-density polyethylene.