The temperature effects between 20 and 160°C on moisture free handsheet were mainly investigated in an aspect of the thermal characteristics of tensile stress-strain curve and of stress relaxation. The stress-strain curves were measured at different straining rates from 0.2 to 50 mm/min. The results are summarized as follows :
(1) The tensile strength and modulus decrease linearly with the rise of temperature, but the elongation does not appreciably depend upon the temperature and beating degree.
(2) The relation between tensile strength and modules is independent of the straining rate and temperature. It is conceivable that the straining rate and temperature have consequently similar effect on the load-elongation property of handsheet.
(3) In the relaxation experiments, times required until the initial stress reductions by 40% are about 100 minutes at 80°C and several minutes at 160°C.
(4) Both the time-dependent parameter (
s/σ') observed in tensile testing with different straining rates and the maximum relaxation rate (
F) in the relaxation process, increase with the rise of temperature.
(5) From the results described above, it is concluded that the flow property of handsheet increases with the rise of temperature.
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