Consider the hard drives of yester-year and more recent. They had a hole for pressure equalization (to control the bulging of pivot fix-points) with a patch of Gortex(R) covering the hole to control liquid transfer. Water vapor could come and go with temperature and pressure variation and they held some of our most precious data.
WVTR (water vapor transmission rate) for plastics is well understood.
Additionally, once you get moisture in a sealed container: at that temperature the partial pressure of the saturated water vapor becomes significant (about 5-psi at 60-deg C, that means the dry gas partial pressure of a mono-gas is only 9.7-psi while it is 14.7-psi dry gas mono-gas outside (60-C and dry)); this increases the dry gas partial pressure differential of the gas components and this drives up gas transmission rates for plastic. Consider a sealed baggie with a moist towel enclosed (put it in a dry 60-deg C oven). Over time (1-day is noticeable, keep it going for longer to see a major effect) the baggie inflates because of the differential dry gas partial pressures inside and outside according to the gas diffusion rates (for that plastic, that too is well know). The baggie inflates until the internal pressure, 19.7-psi, produces a drygas partial pressure equal to the outside, (19.7-psi combined dry gas and water vapor - 5-psi water vapor) inside = 14.7-psi dry gas outside, or the baggie ruptures.
Modern Plastics Encyclopedia (which was a monthly journal) compiled data for this phenomena, and how to use it, back in the 80's through 90's (maybe even before).