Clear and chemically resistant material 1

[diepe]

Hi,

I am looking for a material that has the following properties:
[ul]
[li]Optically clear - comparable to acrylic[/li]
[li]Chemically resistant to IPA[/li]
[li]Chemically resistant to glutaraldehyde[/li]
[li]Chemically resistant to PBS (phosphate buffered saline)[/li]
[li]High enough impact strength to survive a drop of 6 ft[/li]
[/ul]

This material will be made into a tool (approximately the size of a computer mouse) that soaks in solution for about 16 hours per day. So chemical resistance to IPA and glutaraldehyde is extremely important.

Initially, polycarbonate (PC) looked like the proper material to use. But I have since found a few conflicting chemical resistance tables for PC in IPA. Per thread334-315669, polyamide (PA) looks like a good candidate as well, but I am having a hard time chemical resistance data in glutaraldehyde.

Any help or pointers to different candidate materials would be extremely helpful!

Thank you much,

Eric

 

[rickfischer51]

What do you mean by PA? Nylon? Most nylons are semicrysstaline and therefore not clear. There are some high performance Nylon 12 materials that have very small crystals and are clear, such as EMS-Grivory Grilamid TR-55. Is this what you are looking at? We used it for a telecommunication connector component that had all kinds of crazy chemical resistance requirements. The semicrystaline structure gives better chemical resistance than an amorphous material like PC. I calculate the following Hildebrand solubility parameters: IPA = 11.49, glutaraldehyde = 9.32, nylon 12 = 8.86. The nylon is within 1 of the glutaraldehyde, so that's a problem. This could be misleading, as PA exhibits hydrogen bonding that is not accounted for with Hildebrand coefficients. Hansen solubility parameters might give a better indication, but I think they cannot be calculated and are purly empirical. Finding these might be tough.

 

[diepe]

Yes, I was referring to transparent Nylon 12. I was not aware of the Hildebrand solubility parameter before, so that will be a good way to ballpark the material's performance.

Thanks Rick

 

[cloa]

Maybe you should try a ceramic like ALON- Aluminium Oxynitride- you probably need testing but it probably be insensitive to the chemicals involved. Its tough probably tough enough for impact.

http://www.eng-tips.com/threadminder.cfm?pid=1529

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[diepe]

Ckoa, ALON looks like it would be a good candidate too. I did not know transparent ceramics existed. I will look further into using ALON. Thanks much!

 

[Demon3]

I can think of a couple of good candidates but the best one is probably COC (cyclic olefin) for example Topas:

http://www.topas.com/tech-center/performance-data/chemical-resistance

All the best,

Chris

Chris DeArmitt - PhD FRSC

Plastics & Materials Consulting

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