Water absorption

[GilPolymers]

Hey all,

Finally I think that I found a really nice forum that can help me!

It will be nice be helped and help people here...

Well... My question!

I would like to know if someone know where I can fine equations describing the water absorption process of polymers.
I know some simple equations that are user to analysis of barrier properties of polymers but I'm looking for something different!

I am looking forward for your answers!

Thanks

Pedro

 

[patprimmer]

There are two aspects to water absorption

1) Attraction of water to the surface which reaches equilibrium almost instantly.

2) Diffusion of water through the polymer as the water seeks uniform distribution. This can be very slow and is dependant on a number of factors such as concentration gradient, temperature, crystallinity or micro structure of the specimen.

Regards

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[rodneybennet]

I do not exactly know what you are looking for, as there are many equations and formulae related to diffusion. I will try to list some of the water diffusion situations below in a systematic manner:

Binary diffusion of e.g. water in a polymer, is one of the more simple situations. This can often plainly be described by a diffusivity x solubility = permeability.

If a reinforced polymer or a multilayer structure - a laminate - is involved, diffusion of water is getting more complex (because of accumulation at an interface of - for example - a fibre, a simultaneous chemical reaction somewhere, or the fact that subsequent materials have different degree of water diffusivity and solubility).

If more than one component is diffusing at the same time, such as the case in diffusion of an aqueous solution or a mixture, the analysis is even more complex.

However, it’s a good thing to commence with the basic fundamentals, hopefully this description is helpful to you:

http://www.composite-agency.com/messages/3108.html

Regards,