Page 97 - 《橡塑技术与装备》英文版2026年3期

TEST AND ANALYSIS

Figure 6 LAR and MAR of KKNFs SiO 2 /EPDM composite material
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0.072 mm/s and 0.055 g/s, respectively, which decreased carbon layer skeletons. On the one hand, this makes the carbon
by 69.9% and 39.7% compared to EPDM. This further layer structure denser, and on the other hand, the high thermal
demonstrates the significant improvement of KKNFs SiO 2 on stability of silicon oxides themselves can also enhance the
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the ablation resistance of composite materials. ablation resistance of the composite material.
2.6 Analysis of carbon layer
Figure 7 illustrates the morphological structure of the
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ablation surface layer of the KKNFs SiO 2 /EPDM composite
observed under SEM at different magnifications. As shown
in Figure 7(a 1 ), the pure EPDM carbon layer exhibits a loose
and porous structure, accompanied by irregular deposits on the
surface. As shown in Figure 7(a 2 ), when observing the local
carbon layer at a high magnification, it can be seen that the
carbon layer is layered and stacked, with irregular cracks and
pores, indicating that EPDM cannot form a high-strength and
dense carbon layer under ablation experimental conditions. Figure 7 SEM images of the char layer on the ablated
surface of EPDM (a1-2) and 5-KKNFs SiO 2 /EPDM (b1-2)
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Therefore, its linear ablation rate and mass ablation rate are
relatively high. Figures 7(b 1 ) and (b 2 ) depict the morphology of 3 Conclusion
the ablation carbon layer of KKNFs SiO 2 /EPDM. Compared
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(1) KH550 can significantly enhance the interaction
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to EPDM, the carbon layer of KKNFs SiO 2 /EPDM is the most
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between KNFs SiO 2 and EPDM, thereby increasing the
dense, with no obvious pores; further observation at a high bonding rubber and crosslinking density of EPDM.
magnification reveals that nano-silica has been transformed
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(2) With the increase in the amount of KKNFs SiO 2 /
into nano-sized silicon oxide particles and a skeleton structure.
EPDM, the tensile strength and elongation at break of EPDM
During ablation, a large number of Si-O bonds on the surface continue to increase. When the amount of KKNFs SiO 2 is 5
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of KKNFs SiO 2 are opened during pyrolysis, forming a parts, the comprehensive performance of EPDM is optimal.
refined cross-linked network structure and abundant SiOx after
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(3) Compared to EPDM without filled KKNFs SiO 2 ,
carbonization. Driven by the pyrolysis gas flow, the molten
the tensile strength and elongation at break of the 5-KKNFs @
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SiOx on the surface of KKNFs SiO 2 reacts with hydrocarbons SiO 2 /EPDM nanocomposite increased by 235.5% and 65.4%,
to generate irregular SixOyCz spherical particles. These
respectively, while the linear ablation rate and mass ablation
spherical particles have a high specific surface area, which can
rate decreased by 69.9% and 47.6%, respectively.
adhere to more residual carbon, filling the pores between the
Vol.52，2026 ·51·