Origin of the Cell Structure

To aid in comparing relative compatibility and solvating power of monomers and polymers, the solubility parameter 5, a measure of attractive forces between molecules (Tobolsky, 1960), may be used. This parameter 

In general, if two different polymers or monomers have similar values of 3, they will tend to be mutually soluble. 

Using the case of HiPS formation as an example, it can be seen from Table 3.1 that the solubility parameter of styrene is significantly closer to that of polystyrene than to that of polybutadiene. Predictably, then, styrene will swell the nascent polystyrene in preference to polybutadiene, and the locus of polymerization will center increasingly in the polystyrene phase as polymerization progresses. 

---