In case of WPVC composites, the results with respect to flexural
test at difference temperatures are shown in Fig. 7 and Table 3.
Similar behaviors as tensile and compressive tests were obtained
in which the flexural properties of WPVC composites were
decreased as increment of temperatures. High reduction in flexural
strength (39.6%, 44.4%, and 59.3%) was obtained when the temperatures
were increased from 25 C to 50 C, 25 C to 60 C, and 25 C
to 70 C, respectively. Also, high reduction in flexural modulus of
elasticity (29.6% and 40.0%) was also obtained when the temperatures
were increased from 25 C to 60 C and 25 C to 70 C. For the
same temperature range, the properties at large deformation of
flexural strength gave more sensitive to the temperature change
than the properties at small deformation of modulus of elasticity.
Moreover, normalized MOE & MOR as a function of temperature
for flexural test were presented in Fig. 8. These empirical models
obtained from a curve fitting method can be used to predict the
flexural properties of WPVC composites at specified temperature.
The results of wood/ HDPE composites as shown in [24] were also
used to compare with the results of WPVC composites. The
obtained results show that the flexural strength of WPVC composites
approximately decreased 40% while flexural strength of wood/
HDPE composites decreased in the range of 30–60% depending on
mix proportion of wood composites for the temperatures in range
of 25–50 C. For the flexural modulus of elasticity comparison
between WPVC composite and wood/HDPE composite, the same
trend of results was obtained in which WPVC composites gave
lower effect due to temperature change than that of wood/HDPE.
For the temperature change from 25 C to 50 C, the flexural modulus
of elasticity of WPVC composites decreased only 8.2% while it
decreased significantly in the range of 43–55% for wood/HDPE
composites.