Interesting chart.
It is for long term exposure however. How long would it need to be contained?
You were saying you wantedto be able to remove the side of it for access.
Santoprene, on the extreme right of the chart, has an A rating. It comes as a flexible rubber tubing. Perhaps it could be used as an O-ring type seal.
See
OMEGAFLEX® Santoprene Flexible Rubber Tubing it is mailorder.