Dear Margaret Motsi ,

If I understood correctly your question, for the application you mention, the liner films would require certain performance when it comes to different properties. I could imagine some mechanical resistance, some chemical resistance, some thermal stability, maybe some hydrophobicity or some repellence to solvents, or oils, or something like that, among other properties.

Each one of these properties will be affected by the environmental conditions, specially pressure and temperature. Just thinking about an example: if you require a good resistance to compression, the pressure is a very important parameter to consider, or maybe degradation due to being in a harmful atmosphere, or so.

Each one of the mentioned polymers behaves different against solvents, atmospheres, pressures, aging and temperatures, because their resistance/characteristics/behaviour mainly depends on their chemical structure.

In the case of polymers, like the ones you mentioned, temperature is one of the properties that is usually critical, since heating and cooling a polymer might cause degradation of the structure, thus a detriment in their mechanical properties. Another property is solvent resistance and aging in oxidizing atmospheres as well. Again, this influences the structure of the polymer, thus changing their properties.

If you are looking to compare "how much" does the temperature or the pressure influences the long-term performance of your films, I would suggest to start with temperature if you are considering some experiments.

Finally, just to finish, a common strategy to overcome the limitations of each polymer, is, as you said, to combine them. But this approach need to be done carefully, due to the incompatibility of the polymers. Sometimes it is better to use just the pure polymers, sometimes is better to mix them, and normally there is an optimum in the mixing ratio in which the properties are the best.

Hope this helps!