Utilizing Mixed Nanofillers to Control Crystallization Induced Ordering

The technique of controllably tuning nanoparticle ordering in semicrystalline polymers by crystallizing at very slow growth velocities (i.e. high temperatures) represents a very interesting physical situation. While organized PMMA-g-silica fillers have been shown to further enhance the mechanical properties, the particles’ inherent effect on the crystallization process leads to significantly longer processing times and lower degrees of crystallinity than is desirable. To combat this, a mixture of fillers of different sizes (specifically a bimodal distribution) is used to simultaneously increase the rate of crystallization, through nucleation, while allowing smaller fillers to continue to organize. This provides the simultaneous benefit of adding another level to the hierarchically ordered system. By tuning the relative size of either particle or aggregate one can optimize this nucleation effect while benefiting from the structural reinforcement of the secondary filler.