3.2. Rheological properties of PLA and wood fiber reinforced
bio-composites
The flow behavior of polymer is very crucial to understand
in selecting the processing conditions of polymer
composites and also designing the processing equipment’s
such as extruder, die and injection molding machine. In
this work, the rheological studies provided an important
viscosity data of neat PLA and wood fibers reinforced biocomposites
at a temperature of 180 C. Based on these
results, the temperature profile of the extruder and injection
molding machine was set in developing smoother
end products. From the flow curves, the viscosity of PLA
and its bio-composites can be characterized. Shear viscosity
of PLA and PLA based bio-composites showed shear rate
dependent viscosity with the constant temperature. Non-
Newtonian character was observed for all cases which
has positive influence in polymer processing. As shown in
Fig. 4, the viscosity of PLA and wood fibers reinforced
bio-composites were sharply decreased showing shear
thinning behavior while increased shear rate. The shear
viscosity of PLA/WP/Bioadimide composites became lower
than that of PLA/WP composites when shear rate was
increased. It is noteworthy that the multifunctional bioadimide
played a vital to reduce the viscosity in the composite
system. Consequently, the processability of the biocomposites
was remarkably improved whereas without
bioadimide the processing of bio-composites was not smooth. Addition of small amount of bioadimide is able to
reduce the viscosity within the low shear rate region which
indicated that the low energy is required to process the
materials. However, in the high shear rate region, the viscosity
of both bio-composites was found almost equal.