Page 86 - 《橡塑技术与装备》英文版2026年1月
P. 86
HINA R&P TECHNOLOGY AND EQUIPMENT
Based on the fractional strain energy factor at fracture, an that the responses are generally consistent for most testing
(T × E ) before aging
b
b
empirical expression is established to quantitatively describe times. At the same aging temperature, the rate constant of 1#
=
（
TE） f
(T × E b )
b
after aging
the observed aging properties, as shown in Equation (2): sample is higher than that of 2 sample, indicating that sulfur-
#
vulcanized samples have poorer heat resistance than peroxide-
1/ (TE ) − 1/ a = k t (2)
'
'
f
In the formula, (TE) f represents the fractional strain vulcanized samples. For the same sample, the higher the aging
ln k = − (E / RT + ln A temperature, the larger the rate constant, with the reaction rate
）
energy at time t; k' is the effective rate coefficient at
a
increasing by 2~3 times for every 10°C increase. In this study,
temperature T; a is the intercept factor. This rate k refers
) −
1/ (TE
k t
'
1/ a =
'
f
to the overall performance degradation rate of a specific the empirical rule of rate is not a simple constant value. When
'
ln '
'
E
/ RT +
A
#
）
ln k = −（
vulcanized rubber sample. The value of k can be determined the aging temperature increases by 10°C, the rate constant of 1
a
#
sample increases by 1.5~2 times, and that of 2 sample increases
by regression analysis of experimental data using the slope
'
'
'
E
A
1/ a ÷
' t =
f −
exp −
1/ (TE）
/ RT）
（
a
over time at a specific temperature. As shown in Tables 2~5, by about 2 times, indicating an intensified aging degree. The
#
the tensile properties of 1 and 2 EPDM vulcanizates at four relationship expressed by Equation (2) can conveniently
#
aging temperatures are presented. The fractional strain energy describe the aging behavior of EPDM compounds in this
was calculated based on the test results in Tables 2~5, From study over a linear time period. As components requiring heat
the figure 2 and Table 6, it can be seen that the correlation resistance aging, the use of low-sulfur and peroxide curing
coefficients of the regression equations for 1 and 2 samples systems, as well as the selection of composite components, can
#
#
improve the heat aging performance of EPDM compounds.
at different temperatures are above 0.986, indicating a good
correlation, especially in the initial stage, which suggests
Table 6 Relation equation between reciprocal of strain energy and aging time under different aging temperatures for
test samples
1 # 2 #
Temperature/ ℃
Trend equation Rate constant k' R 2 Trend equation Rate constant k' R 2
100 y=0.001564x+1.210 0.001564 0.992 y=0.000875x+1.213 0.000875 0.993
120 y=0.002338x+1.354 0.002338 0.989 y=0.001770x+1.158 0.001770 0.987
130 y=0.005007x+1.462 0.005007 0.989 y=0.004045x+1.184 0.004045 0.994
150 y=0.020697x+1.128 0.020697 0.986 y=0.0153x+1.077 0.01530 0.988
Figure 2 Change in reciprocal of strain energy of the sample with aging time
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