Applications of various spinodal decomposition theories to small angle light scattering experiments of polymer blends

Abstract

This research concerns with the comparison of the kinetics theories of the autonomous phase separation of polymer blends at high temperatures (Spinodal decomposition, SD). Two sets of light scattering data which consist of intensity, angle and times were used. The first one is the blends of Tetiametnyl Bisphenol A polycabonate (TMPC) / Polystyrene(PS) at 30%,50% and 70% of TMPC at various temperatures. The second one is the blend of Polystyrene co maleic anhydride (SMA)/ Polymethyl methacrylate (PMMA) at 20%, 30%, and 40% of SMA at 210 °C. The light scattering data was examined and compared with predicted values from various theories. There are four famous kinetics theories, which have the data to support the precision of the predictions that used in this study. The well-known theory of Cahn-Hiilard has been used. Further more, the Langer, Bar-on, Miller's theory and the theory of Nauman, which were modified from the Cahn Hilliard’s theory, was investigated. The new theory from Akcasu was also fitted with the data. The two sets of data were fitted with these four theories and compare the percent relative average error that deviate from the data. The percent relative average error from each equation were tested and analysed. The observations of the error proved that the new theory of Akcasu was the most versatile theory which can be fitted with the two sets of data. The Langer, Bar-on, and Miller fitted results show the flexible of the usage but the values from the theory cannot be related to the basics properties of the phase separated of polymer blend as Akcasu's theory can. The theories that invented by Nauman and Cahn-Hilliard, can be well fitted only in the beginning of the spinodal decom position process. However, we hardly conclude the validity of the theories because of the few pairs of data observed.