Engineering news
Bioengineers at The University of Nottingham are trialling how to use prawn shells to make biodegradable shopping bags, as a green alternative to oil-based plastics, and as a food packaging material to extend product shelf life.
The material for the affordable eco-friendly bags is being optimised for Egyptian conditions, as effective waste management is one of the country’s biggest challenges.
Natural biopolymer products made from plant materials are a green alternative growing in popularity, but with competition for land with food crops, it is not a viable solution in Egypt.
This new project aims to turn prawn shells, which are a part of the country’s waste problem, into part of the solution.
Dr Nicola Everitt, from the Faculty of Engineering at Nottingham, said: “Non-degradable plastic packaging is causing environmental and public health problems in Egypt, including contamination of water supplies which particularly affects living conditions of the poor.
“Use of a degradable biopolymer made of prawn shells for carrier bags would lead to lower carbon emissions and reduce food and packaging waste accumulating in the streets or at illegal dump sites. It could also make exports more acceptable to a foreign market within a 10-15-year time frame. All priorities at a national level in Egypt.”
The research is being undertaken to produce an innovative biopolymer nanocomposite material which is degradable, affordable and suitable for shopping bags and food packaging.
Chitosan is a man-made polymer derived from the organic compound chitin, which is extracted from prawn shells, first using acid (to remove the calcium carbonate “backbone” of the crustacean shell) and then alkali (to produce the long molecular chains which make up the biopolymer). The dried chitosan flakes can then be dissolved into solution and polymer film made by conventional processing techniques.
Chitosan was chosen because it is a promising biodegradable polymer already used in pharmaceutical packaging due to its antimicrobial, antibacterial and biocompatible properties.
The second strand of the project is to develop an active polymer film that absorbs oxygen. This future generation food packaging could have the ability to enhance food shelf life with high efficiency and low energy consumption, making a positive impact on food wastage in many countries. If successful, Dr Everitt plans to approach UK packaging manufacturers with the product.
The research also aims to identify a production route by which the degradable biopolymer materials for shopping bags and food packaging could be manufactured.