When I soak in the bathtub, I use a white inflatable plastic pillow (vinyl, possibly). It came with instructions to always wash the pillow after use because body oil will degrade the plastic. I’ve noticed that even though I do this, areas that my body always touches have become less flexible and slightly discolored. Compared to other areas of the pillow, it’s quite apparent.
Also, everybody knows vaseline will weaken a latex condom.
The only reference I could find related to my question said “Unvulcanized [uncured] rubber is soluble in a number of hydrocarbons, including benzene, toluene, gasoline, and lubricating oils.” But even latex for condoms goes through a vulcanizing process, so I’m unsure as to whether that’s applicable.
So can someone answer my question? Thanks in advance for any help.
Ok - the answer here is strictly for vinyl. But you can deduce for other plastics too. I am assuming that you have not gone through a course on polymers - so I try to make it as simple as possible. I have quoted from websites that explain it better.
Many polymers resins contain additives which enhance their end-use properties, impact stability, color, resistance to water, rigidity, etc. One such additive is termed a plasticizer because it makes the polymer pliable ( strictly speaking - It lowers the glass transition temperature of somewhat rigid amorphous or semi-crystalline polymers to the point where they can be used at or below room temperature.) How do plasticizers do their job?
It’s simple. PVC consists of long chain polymers with large (high molecular weight) strands of molecules. Plasticizers, such as phthalate esters, are liquids. The processing conditions – involving heat and sometimes pressure – force the polymers and the liquids together. In the new state, the liquid acts s an internal lubricant and allows the polymer chains to move relative to each other, i.e., provides flexibility. This material then can be molded or shaped into a variety of useful products. *
Now these plasticizers, as you would expect are soluble in water and more so in oil. See Here. So as you remove the plasticizer with your body oil, that area becomes “stiff”.
Hope that answers your question. Don’t confuse it with vulcanization, although some concepts are similar there, its not the same.