Study on the Phase Behavior of EP/TPU Blends by Using the Small Angle Light Scattering Method
Guangxian Li, Qi Yang, Yajiang Huang, Yimin Mao
Dept of Polymer Materials, Sichuan University
P.R.China

Keywords: Phase behavior, EP, TPU


Elastomer-modifying is often used to improve mechanical properties of epoxy(EP) resin, and it has been found that the blend of EP with thermoplastic polyurethane(TPU) is a fairly effective system for this purpose. In this article the phase behavior of EP/TPU blends was investigated by time-resolved small angle light scattering (SALS) analysis. The correlation distance (ac) and mean square average dielectric constant fluctuation of EP/TPU blends were calculated. Evolutions of the domain sizes of EP/TPU blend were discussed under the isothermal curing condition. The results showed that the cured process of EP/TPU was a typical spinodal decomposition and can be well described by Cahn-Hilliard linearized theory at the early stage. With the cure development, the domains grew up and kept constant after 60 minutes. During the early blend cure process, the correlation distance (ac) and mean square average dielectric constant fluctuation of EP/TPU blend increased rapidly, from 0 to 1.00 and 0 to 118, respectively, if the experimental time was from 145s to 1080s. After that, the domains of the blend began to coalesce resulting in the decrease of mean square average dielectric constant fluctuation and increase of ac, which will keep constant after 3210s when ac and mean square average dielectric constant fluctuation are 1.30 and 32, respectively.