i hear it's extremely cold out there
The sun-side of this parasol will be all melty, while the shade side will be extraordinarily chilly. Whatever it is made of, will need to withstand that extreme thermal gradient.
If the temperature of the moon is anything to go by, it's hot but not too hot. According to NASA:
>Temperatures near the Moon's equator can spike to 250°F (121°C) in daylight, then plummet after nightfall to -208°F (-133°C).
https://science.nasa.gov/moon/weather-on-the-moon/
Something like aluminum foil should work fine.