Abstract:
High density polyethylene (HDPE) and cellulose (CELL) were used to
prepare the samples used in this study. A fungal strain was isolated
from the dumpsite capable of adhering to HDPE surface.The fungal
strain was identified as Aspergillus niger. Blend composition was
varied and the effect of Aspergillus niger on the creep properties
investigated.Creep measurements were performed at 30 oC, 40 oC, 50
oC and 60 oC. Viscoelastic behavior of HDPE/CELL blends was found
to be governed by temperature, CELL loading and inoculation. As
expected with CELL loading, creep performance of the HDPE/CELL
blends improved on addition of CELL but decreased with temperature
increase and on inoculation. Creep compliance and creep strain
increased with inoculation indicating that A.niger ruptured the blends
hence increased chain motion. Wiliam-Landel Ferry (WLF) model
offered a better long-term prediction based on the short-term creep data
by shifting curves along the logarithmic time-axis to obtain a master
curve. Time-temperature superposition technique produced smooth
master creep curves through horizontal shifts.
