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The phase separation behavior of poly(vinyl methyl ether)/polystyrene semi-IPN
Abstract
The effect of crosslinking on the phase stability and phase separation behavior of poly(vinyl methyl ether)/polystyrene semi-IPN was studied by light scattering. The cloud point temperature was measured as a function of degree of crosslinking and found to be constant within experimental precision. The result of this experiment was combined with a theoretical prediction of the phase diagram to determine conditions for the following experiment. Wide angle light scattering was used to quantitatively analyze the mechanism and dynamics of the thermally induced phase separation with respect to the crosslinking density and the thermal condition. An apparatus with a one dimensional diode array was used to simultaneously monitor a wide range of scattering angles. Analysis of the early stages of phase separation indicates that the spinodal temperature remained virtually constant whether or not crosslinks were present in the system. This was demonstrated to be consistent with theoretical prediction. However, the apparent diffusion coefficient decreased dramatically with the introduction of crosslinks thus the initial phase separation was slowed down significantly. The final scattering intensity was shown to decrease with increasing crosslinking density. The scattering vector dependence of the scattering intensity was negligible compared with its overall time dependence. A plateau region was observed for some of the scattering intensity data of the semi-IPN systems with respect to time. This indicates that the crosslinks restrict terminal phase contrast and not the size of phase.
Subject Area
Polymer chemistry
Recommended Citation
Aoki, Osamu, "The phase separation behavior of poly(vinyl methyl ether)/polystyrene semi-IPN" (1990). Doctoral Dissertations Available from Proquest. AAI9022661.
https://scholarworks.umass.edu/dissertations/AAI9022661