Studies on the miscibility and phase structure in blends of poly(epichlorohydrin) and poly(vinyl acetate) |
| |
Authors: | E El Shafee |
| |
Affiliation: | Department of Chemistry, Faculty of Science, Cairo University, 12613 Giza, Egypt |
| |
Abstract: | The miscibility of atactic poly(epichlorohydrin) (aPECH) with poly(vinyl acetate) (PVAc) was examined under two different conditions: (i) in dilute solution, using vicometeric measurements and (ii) as cast films, using differential scanning calorimetric (DSC) and FT-infrared spectroscopy. Phase separation on heating, i.e. lower critical solution temperature (LCST) behavior of the aPECH/PVAc blends was examined by the measurement of transmitted light intensity against temperature. From viscosity measurements, the Krigbaum-Wall polymer-polymer interaction (ΔB) was evaluated. The DSC results show that the aPECH/PVAc blends are miscible as evidenced by the observation of a single composition-dependent glass-transition temperature (Tg) which is well described by the Couchman and Gordon Taylor models. The Flory-Huggins interaction parameter (χ12) calculated from the Tg-method was negative and equal to −0.01, indicating a relatively low interaction strength. The FT-IR results match very well with those of DSC. The cloud point phenomenon is thermodynamically driven but phase separation, once taken place, is diffusion controlled in normal accessible time. |
| |
Keywords: | Atactic poly(epichlorohydrin) Poly(vinyl acetate) Miscibility |
本文献已被 ScienceDirect 等数据库收录! |
|