Polystyrene Particles

[chadzeilenga]

Hello all,
I was assigned a new project here at work and it involves the use of Polystyrene Particles in the 5-6 micron sizes. Does anyone have any experiance with these? I know absolutely nothing about them, so any information is useful.

 

[Demon3]

There has been loads of work on such particles. They are cheap and easy to make, mostly inert (unreactive) but you can derivatise them in order to stick other molecules on them. If we knew a bit more about what you plan to do with them it would make it easier to say something that could help you. You can get such particles in a variety of forms from Polysciences I believe.

 

[chadzeilenga]

We are planning to use the particles in a Silicone solution to reduce the effect of temperature changes on the material. We use the silicone in a rotational damping application. Our torque of the damper is greatly affected by temperatures from -40C to 90C. We have experimented with custom blends of silicone with modified Phenyl or Methyl amounts but have not had much success.

 

[dwightdixon]

Polystyrene changes properties pretty dramatically around 165 F so 90 C usage is out of the question.

 

[Demon3]

Yes, polystyrene will begin to soften and swell at 90C but perhaps that's what you are aiming for? The polystyrene expands a bit and compensates for the dropping viscosity of the silicone. I know such technologies are used to keep the viscosity of engine oil constant with changing temperature.

 

[chadzeilenga]

If the polystyrene softens & swells while it is in the silicone will it absorb the silicone and then retain that swollen state once it has cooled, or even at RT? What will happen in colder temperatures? Is the rate of expansion faster than that of the silicones dropping viscosity?

 

[Demon3]

I prefer not to guess exactly what would happen but you can easily measure the viscosity on heating and cooling using a rheometer. You will find labs who can do that for a fee if you don't have the equipment.