Among the four basic packaging materials, petroleumbased
plastic materials have been widely used since the
middle of the twenties century. It is mainly because
they are cheap and convenient to use with good
processing property, good aesthetic quality, and excellent physico-chemical properties. More than 40% of the plastics
are used for packaging and almost half of them are used for
food packaging in the form of films, sheets, bottles, cups,
tubs, and trays, etc. After their useful life, it is desirable for
the packaging materials to biodegrade in a reasonable time
period without causing environmental problems. Though
the synthetic plastic packaging materials have been widely
used for the packaging of various types of food, they caused
a serious environmental problem since they are not easily
degraded in the environment after use.