Bio polymers
Biopolymers are a special class of polymers found in nature, starch, protein and peptides. DNA and RNA are all examples of biopolymers, in which monomer unit, respectively are sugars, amino acids and nucleic acids.
A major difference between biopolymers and polymers can be found in their structures. Bio polymers inherently have a well defined structure. Many biopolymers spontaneously "Fold" in to characteristic shapes, which determine their biological functions and depend in a complicated way on their primary structures. Structural biology is the study of the shapes of biopolymers. In contrast most synthetic structures have much simpler and mere random or statistic structures. Another important difference is the lack of a molecular mass distribution in most biopolymers. As their synthesis is controlled by a template direct process in all bio polymers are alike, they all contain the same sequence and numbers of monomers and thus all have the same mass. This phenomenon is called monodispersity in contrast to the poly dispersity encountered in polymers.
Some biopolymers such as Polyacetic acid, Zein and poly 3-hydroxy butyrate can be used as plastics replacing the need for polystyene or polyethylene based plastics.
Biodegradable polymers
Many synthetic polymers are produced and utilised because they are resistant to chemical and physical degradation. These polymers are resistant to degradation and present disposal problems when their usefulness ceases. Substitution of natural monomers in to synthetic polymers produces polymers that are more easily biodegraded, however such polymers lack properties such as water resistance, that make current polymers so useful. Bio degradable polymers must over come such physical problems as well as lower their costs of production, which currently limit the economic possibility of such biodegradable polymers.
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