The Environmental Polymers Group
(EPG) of the United States has developed a new biodegradable
plastic wrapper that is soluble in water under specific
conditions. EPG has been able to successfully modify
polyvinyl alcohol (PVOH), a polymer used to coat drug
capsules, for use in conventional equipment. This
development facilitate production of PVOH with the
quality required for commercial applications.
PVOH, water, glycerol and a small
quantity of silica are mixed together to form a `pre-blend'
flakes. These flakes must then be melted to form pellets.
The pellets are shipped to facilities that, with some
minor modifications, can process them using standard
melt-processing equipment into various products. The
temperature at which the product dissolves in water
is determined during the pelletization process. Micro-organisms
degrade the dissolved PVOH into carbon dioxide, water
and biomass.
