Ultrasonic may helps. However the frequency and the time exposed to sonic may damage the sample. We have use sonic to disperse CNTs and graphite in polymeric matrices and shown that sonic help to disperse the filler without damaging the system.
Basheer, I think it is very important to know how is your system. It is not the same to mix short fibers or small particles into a melt polymer or polymeric solution. In each case you will get particular dispersion or distribution of your filler. Here, you have read the comments and all of them are for particular system, someone in solution and other in melt polymer. Could you tell us, how is your system? In order to improve the discussion. Thanls.
first of all you should recognize parameters affected distribution and dispersion.
for dispersion, shear rate is the main parameter. so each parameters which increased shear rate would increased dispersion too. such as back pressure in extruder, kneading element in screw and some others.
but about distribution;time of mixing would increased distribution but it should be noticed that time has a limited affect.
In extruders, L/D is the most important parameter for distribution. higher L/D means better distribution.
if you need any more explanation, please inform me.
There is an entire chapter (Chapter 5) dedicated to the Preparation of filled polymer systems in the following book:
Aroon V. Shenoy, Rheology of Filled Polymer Systems, Kluwer Academic Publishers, Netherlands (1999).
In section 5.4, there is a detailed discussion on the compounding /mixing variables that affect the quality of the mix. Some variables are more sensitive to changes than others. It is important to study and identify these variables and understand their sensitivity so that the compounding /mixing can be carried out under optimum conditions. Variables affecting compounding operations could be machine variables (mixer type, rotor geometry) or operating variables (mixing time, rotor speed, ram pressure, chamber loading, mixing temperature, order of ingredient addition). You will have to study and understand the effect of each of these variables for your specific filler – polymer matrix combination to find the optimum conditions to achieve the proper level of dispersion and distribution of filler into the polymer. You will get the necessary hints on how to go about this by reading Chapter 5 of the book.
Ultrasonic may helps . How easy/fast the dissolution and dispersion and distribution of fillers into polymers . I am thinking that does the polymer molecular weight of affecting the dispersion and distribution.