Increasing amounts of plastic waste in the
environment have become a problem of gigantic proportions.
The case of linear low-density polyethylene (LLDPE)
is especially significant as it is widely used for packaging
and other applications. This synthetic polymer is normally
not biodegradable until it is degraded into low molecular
mass fragments that can be assimilated by microorganisms.
Blends of nonbiodegradable polymers and biodegradable
commercial polymers such as poly (vinyl alcohol)
(PVA) can facilitate a reduction in the volume of plastic
waste when they undergo partial degradation. Further, the
remaining fragments stand a greater chance of undergoing
biodegradation in a much shorter span of time. In this
investigation, LLDPE was blended with different proportions
of PVA (5–30%) in a torque rheometer. Mechanical,
thermal, and biodegradation studies were carried out on
the blends. The biodegradability of LLDPE/PVA blends
has been studied in two environments: (1) in a culture medium
containing Vibrio sp. and (2) soil environment, both
over a period of 15 weeks. Blends exposed to culture medium
degraded more than that exposed to soil environment.
Changes in various properties of LLDPE/PVA
blends before and after degradation were monitored using
Fourier transform infrared spectroscopy, a differential
scanning calorimeter (DSC) for crystallinity, and scanning
electron microscope (SEM) for surface morphology among
other things. Percentage crystallinity decreased as the PVA
content increased and biodegradation resulted in an
increase of crystallinity in LLDPE/PVA blends. The results
prove that partial biodegradation of the blends has
occurred holding promise for an eventual biodegradable
product
Description:
Journal of Applied Polymer Science, Vol. 124, 257–265 (2012)