Thermal Properties and Intermolecular Interaction of Blends of Poly(ethylene oxide) and Poly(methyl acrylate)

摘要

Polymer blends of poly(ethylene oxide) (PEO) and poly(methyl acrylate) (PMA) were prepared by solution casting method. Thermal stability of the binary PEO/PMA blends was examined by termogravimetric analysis (TGA). Decomposition temperatures of the binary blends were estimated from the onsets of the weight loss curves of TGA thermograms. The decomposition temperatures of the blends increase when the content of PEO elevates. Hence, PEO has a better thermal stability as compared to PMA. The activation energy of thermal decomposition of each sample was calculated from the initial stage of the decomposition. Quantities of E_A increase when content of PEO increases in the blends. Differential scanning calorimeter (DSC) was used to investigate the thermal properties of binary PEO/PMA blends. An existence of a single and composition-dependent glass transition temperature (T_g) for the blends indicates the miscibility of the PEO/PMA blends. The T_gs of PEO/PMA blends increase when PMA content increases. Furthermore, when PMA is blended with PEO, the crystallinity (X~* ) and melting temperature (T_m) of PEO in PEO/PMA blends are depressed. Thus, the miscibility of the blends in the molten state is in agreement with T_g results. Fourier-transform infrared (FTIR) spectroscopy was used to study the intermolecular interaction of between PEO and PMA in the blends. The characteristic absorbance bands of ether and carbonyl groups of PEO and PMA were examined by FTIR. PEO and PMA only display weak van der Waals interactions in blends. Hence the miscibility of PEO and PMA in the blends may be more towards the entropic effect instead of the enthalpic effect.