We’ve all heard of organic cotton, but perhaps one day soon chicken suits could be the latest thing in eco-friendly clothes.
And that doesn’t mean that we will be walking around dressed up as chickens, but that a new process could be developed to make renewable fibres from the protein in chicken feathers, called keratin, as well as from gluten in wheat, both of which are currently produced industrially in huge quantities around the world.
Andrew Poole, Jeffrey Church and Mickey Hudson from CSIRO Materials and Science Engineering in Australia discuss the potential for these new eco-friendly fibres in this week’s edition of the journal Biomacromolecules.
These wouldn’t be the first fibres to be made out of proteins. Wool and silk are after all made of protein. And back in the 1930s, several companies tried making fibres from various sources including milk, peanuts and soybeans.
The problem is that all these fibres are extremely weak when they get wet, which means they wouldn’t survive in your washing machine. The reason behind this is that when the protein molecules are dry, hydrogen bonds hold the long thin polymer molecules together making the fibres strong, but when water comes along, those hydrogen bonds stick the molecules to water instead of each other.
One way modern-day textile manufacturers could get around this problem may be to add nano-particles to the proteins since this can drastically improve their wet-strength by providing a reactive surface that the protein molecules cling to. Possible candidates include clay nanoparticles, carbon nanotubes and perhaps most encouragingly, cellulose nanoparticles known as whiskers which have the benefits of being renewable and biodegradable.
An alternative solution could be finding a method of successfully cross-linking the protein molecules. Metal catalysts are one option, which tend to be expensive and not especially environmentally sensitive, and another possibility is reacting the proteins with sodium sulphide.
The good thing about these potential new fibres is that the raw materials are cheap, they ultimately come from renewable sources and they are widely available around the globe, and they can be processed using the same textile machinery and dyed using the same dyes as more conventional fibres.
These new fibres could also help see an end to the millions of tonnes of unwanted feathers that are sent to landfill every year from the meat industry, and could help reduce our reliance on non-biodegradable, oil-based man-made fibres that currently account for over half the fibres produced in the world every year adding up to an enormous 38 millions tonnes.
How the fibres are made:
The first step is to dissolve the protein, then the liquid is pumped through a fine spinneret into a coagulation bath, usually containing a salt solution that dehydrates the protein causing it to come out of solution and form a filament. The filament is then stretched between rollers, pulling the molecules out straight and packing them closely together before they are cross-linked to produce the final fibre.