Granular starch is added to a polymer in order to decrease the cost of the
polymer derivative. Use of granular starch also makes the derivative more
biodegradable. The polymer blend has very similar mechanical properties
to pure polymer. Furthermore, unlike other starch/polyethylene mixtures,
glycerol is not added to the mixture. This reduces the water absorbency
of the final product. The polymer and starch are blended together in the
presence of an interfacial compatibilizer that binds the two components
together.