Enhancement+of+properties+of+Biodegradable+Polymers

The properties of biodegradable polymers can be enhanced in a variety of ways.

Sometimes, biodegradable polymers are so easily degradable that they are unable to fulfill their use. In these cases, the polymers have extremely low thermal stability, and therefore measures can be taken to increase the usefulness of the biodegradable polymer. One example to increase the stability is by the addition of various additives. Alcohol groups are added in order to increase the intermolecular or hydrogen bonding interactions between the polymer. This results in the polymer being more stable and more resistant to decompostion. Another specific additive that has been used is ammonium polyphospahte.

For some applications, such as knee joints, polymers need to flexible and have the ability to slide. A commonly used method to lower the coefficient of friction is to fuse the polymer surface with nanoparticles. These nanoparticles enhance the sliding properties of the polymer. Also, these particles are not easily degraded and therefore, they increase the stability and the rigidity of the polymer.

Figure 1 : Biodegradable polymers can be moulded into various shapes in order to enhance its properties for different applications. The biodegradable polymers used in electrical wires can be modified so as to promote electrical insulation. This is done so that so electrical energy is wasted to the surroundings. The specific polymer can be modified by not allowing the conducting groups of the polymer interact with each other. This is best explained using band gap theory in conjunction with molecular orbital theory. [3] Band theory tells us that in order to achieve electrical conductivity that there must be a close enough separation of a conducting band and a valence band of the insulator. When one then applies molecular orbital theory you see a large separation of conducting band and the valence band. This is best evidenced by the strength of a carbon-carbon bond. The carbon-carbon bond has such a large separation between it's HOMO and LUMO that an electron cannot be promoted to the conducting gap, stopping any electrical conductivity.