swelling of polypropylene or polycarbonate

[1DanD]

Thanks in advance, I'll try not to sound too stupid.

In past projects I've used heptane to swell silicone tubing before inserting the mating part. When the heptane evaporates the silicone shrinks again.

Does anyone know if there is a similar phenomenon for polycarbonate or polypropylene?

I have searched this forum, Googled, searched with GlobalSpec, gone through some books I have, etc. and found nothing on the subject.

If not, I'm looking at heating the outer part.

 

[Demon3]

That method works because the silicone is a rubber / elastomer. PP and PC are not so it won't work well for them, i.e. they won't swell and recover elastically as well as a rubber does. Instead the PC is likely to degrade horrible, i.e. from environmental stress cracking or it will dissolve. For PP it's probably going to be a challenge to find a good solvent to swell it. If I were you I would look at chemical resistance data for PP (you can find a sheet at RTP website) and note the solvents for which PP is not suitable, those are probably ones the swell it.

There is not any memory with less satisfaction than the memory of some temptation we resisted.
- James Branch Cabell

 

[btrueblood]

Can you not warm the body, chill the mating (inserted) part, to acheive the same effect?

 

[patprimmer]

Polycarbonate is very stable to swelling, but as Demon3 says, is very susceptible to solvent stress cracking so attempting to swell it with heat or solvent will be somewhere between futile and disasteros.

PP will swell in some hydrocarbons, but the reactions both ways will be very slow and not likely practical. Heat will soften PP to the extent it might easily snap over then shrink on, but to much heat or stretch will result in a permanent distortion.

Warm one and freeze the other part is the best advice I have seen or can think of.


Regards

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