How does the degradation manifest itself physically?In how much time?
Physically the degradable films would begin to loose their tensile strength and elongation, besides a lowering in its molecular weight. Chemically the structure would show an increase in the rate of formation of carbonyl and hydroxyl groups which can be analyzed in a laboratory. The time again would vary depending on the application and the environment in which the film has to be used. For instance a 15 micron film, suitably modified and kept in a field might breakdown within 15 days. Similarly an 80 micron film suitably modified and stored at 20oC to 25oC might still be strong after 1 year.
