Chickens as a source of plastic

It is generally accepted that the domestic chicken (Gallus domesticus) is descended from the red junglefowl (Gallus gallus) from south-east Asia. The chicken is now found in almost every corner of the world in a bewildering range of breeds, many of which have been specially selected for meat, egg production or ornamental purposes.

The meat industry alone produces billions of birds each year to be sold in fresh, frozen or processed form. Indeed, a brief glance at the shelves of any supermarket will show a range of products only limited by the imagination of food technologists. Add in other forms of poultry — game birds, ducks and food from other avian sources — and what happens? Well for a start you have a huge number of feathers.

Small quantities of feathers are recycled by, for example, adding them to low grade animal food but most of them are simply incinerated or wasted as landfill. However, feathers are made mainly of keratin, and a report from the American Chemical Society describes how to use this to make a form of plastic which can then be used to manufacture thousands of consumer and industrial products.

Amid turmoil growing in the oil producing countries of the Middle East and North Africa, concerns about oil prices and the environmental dangers of oil exploration in deep oceans and the polar regions, a team from the Institute of Agriculture & Natural Resources at the University of Nebraska-Lincoln is looking for plastics derived from renewable sources. They treated chicken feathers with chemicals including methyl acrylate to make films of what they called feather-g-poly(methyl acrylate) plastic.

This plastic has excellent thermoplastic properties: it can be hardened then melted and remoulded time and again, and unlike some earlier bioplastics it also has good water resistance. Feather-g-poly(methyl acrylate) plastic proved to be stronger and more tear-resistant than plastics made from other biological materials such as fruit fibre, bone meal, soya protein or starch and is biodegradable when discarded.