Page 51 - 《橡塑技术与装备》英文版2025年12月

MATERIALS AND FORMULATIONS

Figure 1 The influence of physical blowing agent mass fraction on the density and expansion ratio of foamed silicone
rubber under different molding pressures

different, and the foaming effect is limited.

Figure 3 The influence of hollow glass microsphere
Figure 2 Effect of mass fraction of sodium bicarbonate mass fraction on the density and expansion ratio of
as foaming agent on the density and expansion ratio of foamed silicone rubber
foamed silicone rubber
silicone is 0.4 g/cm , and when the addition ratio reaches 4%,
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2.1.3 Density and expansion ratio of foamed the density of foamed silicone is 0.27 g/cm . When the addition
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silicone rubber filled with hollow glass ratio of foaming agent sodium bicarbonate is 2% and 3%, the
microspheres density of foamed silicone changes little. When using hollow
The influence of the mass fraction of hollow glass glass microspheres, the density and foaming ratio change
microspheres on the density and expansion ratio of foamed slowly when the addition ratio increases from 5% to 8%.
silicone rubber is illustrated in Figure 3. As evident from 2.2 Mechanical properties
Figure 3, the density of foamed silicone rubber decreases as the 2.2.1 Tensile strength
proportion of hollow glass microspheres increases. When the Under non-pressurized conditions, the tensile strength
mass fraction of hollow glass microspheres is 8%, the density of foamed silicone rubber obtained using physical foaming
of foamed silicone rubber is 0.83 g/cm , and the expansion agents, sodium bicarbonate as a foaming agent, and hollow
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ratio is 1.31 times. Hollow glass microspheres are hollow, glass microspheres is shown in Figure 4. As the amount of
transparent, and spherical in shape, primarily serving as a filler foaming agent added increases, the tensile strength decreases;
in foamed silicone rubber. as the density of the foamed silicone rubber increases, the
In summary, as the amount of foaming agent increases, tensile strength increases. When using physical foaming agents
the density of foamed silicone decreases, and the foaming ratio without pressurized curing and molding, the tensile strength
increases. Silicone with physical foaming agent added exhibits of the foamed silicone rubber is 0.7 MPa when the addition
better foaming effect. When the addition ratio of physical level is 2%, and the density is 0.4 g/cm . Shao Shuiyuan et
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foaming agent is 2% without pressure, the density of foamed al. used methyl vinyl silicone rubber as the matrix, added

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