Hardness and Tackiness Testing of a Polymeric Gel

[JohnMerhige]

Hello,

Can anyone give me some guidance on low cost methods for testing the hardness and tackiness of a polymeric gel. The gel is a poloxamer witht he consitency of something like jello.

Thanks

John

 

[Jabberwocky]

I guess it depends on what you need to know the hardness in relation to. You could easily rig up a high-school experiment showing relative hardness, via penetration of a standard object at constant speed say?

Tackiness the same I bet, I've seen some standards where a ball bearing is rolled from a constant height and the distance it takes to stop is computed into a stickiness measurement.

If you need accredited methods you'd have to go to ASTM and see what you can find, they seem to have a method for almost anything.

 

[JohnMerhige]

Thnaks for your thoughts.
I am measuring the hardness/tackiness of one polymeric gel in relation to another one.

Regarding hardness... the gel is quite soft and does not elastically return to its original shape once a force is delivered. Not sure this will work.

 

[Jabberwocky]

What about a dropped weight? This may be more akin to an impact test, but could you measure the depth of penetration of a standard dropped weight, like a ball bearing?

Now that I think about it, some of the hardness measurements really just have to do with what material will abrade the other - the Mohs scale I think. Could you apply something like this? Not with rocks obviously, but with a piece of cloth or something, rub it across the surface of your gel and see how much sticks?

Also, try searching for info about the 'Shore 00' scale. I think that's what's used for gels and the like.

 

[mk2000]

I am not sure if hardness is going to be easy to measure (with a small budget at least). Shore 00 scale is more for elastomers and I don’t know if it can be easily applied to gels.

However thickness (viscosity) is much easier thing to measure in gels. As Jabberwocky mentioned if you are comparing two gels the easiest way to compare viscosity is to measure the speed at which a standard object falls through the fluid/gel. You just have to find a spherical object that will fall through both gels. Also keep in mind that to use the same container for both gels to ensure fluid dynamic effects are the same in both tests as well as initial conditions (drop hight).