chemical resistance of mica

[mjh368]

hello all,
I am interested in a table or data for the chemical resistance of mica. The mica will be used as a filler in a polypropylene part in 40% concentration. any links or tips would be greatly appreciated.
thank you for you time

 

[oldestguy]

mjh368

I'd be surprised if you get an answer here. The civil engineers I have run into have some rudimentary chemical know how, but I think this is the wrong forum for that question.

However, I just now phoned a chemical engineer friend and he may show up with more detail. However, both are apparently mutually compatible and both are inert. It takes certain very strong acids to affect each or the mix.

Car battery cases are made out of the stuff.

This chemical engineer has strong experience in the subject. So stand by for him. He is not currently registered, but will be soon.

 

[rhunter611]

The natural mineral Mica occurs in two forms. The most common is Muscovite, a hydrated Potassium- alumino- silicate which is chemically inert. It may perhaps be attacked by strong double mineral acids such as Aqua Regia or Hydroflouric: I have no data for such reactivity; none is found in the Handbook of Chemistry and Physics. It is commonly used in compounds of Polypropylene at 20% wt. concentration or less to dilute and to increase the Flexural Modulus(stiffness). Such compounding done correctly will fully encapsolate the Mica particles making them unavailable for contact by outside substances. A processing aid such as Calcium Stearate may improve the dispersion of the Mica in the plastic.
Mica is ground finely for use in altering appearance of plastics along with colorants to make the "pearlescent" color effects of many personal care product containers and automobile paints.
Mica and Polypropylene are mutually compatible from 0% to 100% concentration. Polypropylene is known as a very non-reactive plastic because of its high degree of crystallinity. As such it is used as the case for Lead-Sulfuric Acid storage batteries.
Your request asked for reactivity data. What is the substance intended for contact with the compounded plastic?
Mica is mined at Kings Mountain, North Carolina by a company of the same name; perhaps they have data. Please check the web site:

http://minerals.usgs.gov/minerals/pubs/commodity/mica/

for a description of Mica in which the mineral is described as "inert". Good luck with the project!

rhunter611: BS ChE 1963, UT Austin.