A semiempirical derivation of phase domain size in interpenetrating polymer networks

Abstract

SynopsisIn previous papers, interpenetrating polymer networks were shown to display a cellular structure.The phase domain size of polymer I1 was shown to depend inversely on the crosslink density of polymer I. The present paper presents a semiempirical derivation of equations which show quantitatively the dependence of the phase domain size of polymer I1 on the crosslinking density of polymer I, and also on the interfacial energy and the overall composition. If polymer I1 is linear, the dependence on the molecular weight of polymer I1 is also included. The values of the phase domain sizes so estimated are compared with experimental results. While theory and experiment yield good agreement, the semiempirical nature of the equations must be borne in mind.

Effect of the reactivity of a crosslinking agent on the microphase separation in sequential IPNs: A Monte Carlo simulation study

“…4 The phase-separated structure of IPNs depends on both the thermodynamic miscibility of the constituent networks and the kinetic conditions of the crosslinking reaction. Sperling et al 5 found that an increase in crosslinking density leads to a decrease in the degree of phase separation in SBR-PS IPNs. In an SIPN, the crosslinking density of the first network is more important to morphology development than that of the second network.…”

Phase-Separated Interpenetrating Polymer Networks

“…Morphological data showing that IPNs are highly heterogeneous structures allowed Sperling et al [72][73][74] to propose the mechanism of IPN formation called nucleation and growth. A thermodynamic theory of IPN morphology has been developed in [74].…”

“…A thermodynamic theory of IPN morphology has been developed in [74]. Its main assumption is that there are two separate states of polymer I and polymer II separated one from another.…”

“…Early research on the thermodynamics of the domain formation was performed by Donatelli, Sperling, and Thomas [74], who considered the free energy changes connected with surface effects and elastic free energy changes due to swelling.…”

“…In spite of many arbitrary assumptions (including the one stating that a spinodal decomposition process rather than binodal phase separation actually takes place), rather good agreement between calculated and experimental domain diameters for various compositions of IPN and various cross-linking levels was found. It was pointed out that the domain size is very sensitive to the value of interfacial tension [74].…”