Factors affecting the miscibility of simultaneous IPNs and pseudo-IPNs

We present experimental data in support of the principal factors promoting enhanced miscibility of interpenetrating polymer networks (IPNs). These are the match of rates of the crosslinking reactions producing the IPNs, and minimizing the difference in solubility parameter and glass transition temperature of the linear chain components. Long-lived, metastable pseudo-IPNs can be produced if the concentration of the linear component is not too large and the molecular weight is sufficiently large. We also briefly describe the behavior of crystalline linear, syndiotactic polystyrene (syn-PS) and linear isotactic PS as components in pseudo-IPNs of crosslinked atactic PS and poly(methyl methacrylate).