Page 95 - 《橡塑技术与装备》英文版2026年3期

TEST AND ANALYSIS

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Additionally, the surface of nano-SiO 2 contains abundant 5-KKNFs SiO 2 /EPDM increased by 132.9%, 164.1%, and
hydroxyl groups, which facilitate the adsorption and 228.7% respectively compared to EPDM, while the elongation
entanglement of more EPDM molecular chains, thus hindering at break increased by 52.7%, 72.6%, and 65.4% respectively.
the slippage of rubber segments under external forces and However, when the amount of KKNFs increased to 7 parts, the
improving the tensile properties. Compared to EPDM, the nanofibers had an adverse effect on the mechanical properties
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tensile strength and elongation at break of 5-KKNFs SiO 2 / of the composite material. This is due to the agglomeration of
EPDM are increased by 235.5% and 65.4%, respectively, nanofibers within the EPDM matrix caused by their nanoscale
further enhancing the mechanical properties of the composite size, which prevents the smooth transfer of load when
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material. This is because, compared to mKNFs SiO 2 , KKNFs @ subjected to external forces, leading to stress concentration and
SiO 2 , grafted with KH550 containing non-polar alkyl chains, further defects, resulting in a decrease in both tensile strength
exhibits superior dispersion in the non-polar EPDM matrix. and elongation at break.
As shown in Figure 4(b), the tensile strength of 1, 3, and

Figure 4 Stress-strain curve of KKNFs SiO 2 /EPDM composite material
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Table3 Mechanical property parameters of KKNFs SiO 2 / crosslinking reactions, increasing the crosslinking density in
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EPDM composite materials the crosslinked network, restricting the movement of molecular
Sample Tensile strength/MPa Elongation at break, %
EPDM 5.88±0.12 463±9 segments, and forming a barrier to heat transfer through the
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5-mKNFs SiO 2 /EPDM 11.14±0.15 603±34 nano-filler network formed by nano-SiO 2 and nanofibers,
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1-KKNFs SiO 2 /EPDM 13.70±0.67 707±31
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3-KKNFs SiO 2 /EPDM 15.53±0.32 799±58 further enhancing the thermal stability of the composite
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5-KKNFs SiO 2 /EPDM 19.73±0.55 766±24 material.
7-KKNFs SiO 2 /EPDM 12.75±0.36 665±35
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Table 4 shows that the R800 of EPDM is 26.75%. In
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2.4 Thermal stability comparison, the R800 of 1, 3, 5, and 7-KKNFs SiO 2 /EPDM
As shown in Table 4, the temperature at 5% weight loss increased by 0.52%, 5.72%, 13.08%, and 15.96%, respectively.
(T 5 ), temperature at 10% weight loss (T 10 ), maximum thermal As shown in Figure 5(b), the main weight loss stage of the
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decomposition rate temperature (T max ), and residual weight KKNFs SiO 2 /EPDM nanocomposites occurs around 400-
at 800 ºC (R800) of mKNFs SiO 2 /EPDM are all higher than 500℃. The data in Table 4 clearly indicates that as the content
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those of pure EPDM, attributed to the thermal stability of of KKNFs SiO 2 increases, the Tmax of the system gradually
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mKNFs SiO 2 . After modification with KH550, the T 5 , T 10 , increases. Compared to EPDM's Tmax of 453℃, the Tmax
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Tmax, and R800 of KKNFs SiO 2 /EPDM are further improved. of composites with 1, 3, 5, and 7 parts of KKNFs increased
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This is due to the ability of KKNFs SiO 2 to adsorb more to 453.3, 453.5, 454.0, and 454.2℃, respectively. The
vulcanizing agents and accelerators, promoting intermolecular corresponding maximum thermal decomposition temperatures
Vol.52，2026 ·49·