In this study, the influence of space radiation on the properties of methyl
phenyl vinyl silicone rubber (MPVQ) compounds is systematically investigated.
The results reveal that with increasing radiation dose, the appearance of MPVQ
compounds changes from white to pale yellow and then to grayish-yellow, while
their hardness continuously increases. Both the tensile strength and tear
strength of the samples exhibit the S-shaped variation curves with radiation
dose. At a radiation dose of 1 × 10^6 Gy (Si), the tensile strength,
elongation at break, and tear strength decrease by 20%, 89%, and 69%,
respectively. When the radiation dose exceeds 1 × 10^6 Gy (Si), both
the tensile strength and tear strength rebound moderately. However, further
increases in the dose cause both properties to decline again. By contrast, the
elongation at break decreases consistently throughout the dose range. Besides,
the samples are non-flammable in the presence of open flames. According to these
experimental results, the MPVQ products can meet the 15-year service lifetime
requirement for the static spacecraft, although their elasticity and
load-bearing capacity could be substantially diminished, leading to increased
brittleness and susceptibility to fracture under stress. However, some physical
or chemical modification of the MPVQ materials is definitely needed for their
further application in the dynamic mechanism for the long-life spacecraft that
are directly exposed to the space environment. In our opinion, the results shown
in this work could provide some necessary guidance for the further development
of the related materials in the related field.