How to model bidisperse homopolymer mixtures in Synthia

Hi,

I am interested in using Synthia (or any other module available with Materials Studio) to model the mechanical properties (Brittle Fracture Stress specifically) of bidisperse homopolymer mixtures (mixtures of two different molecular weight polymers).  I am new to Materials Studio, and so far have not found a way of modeling this.  Any suggestions?

Thanks.