The effects of mixing with poly (methyl methacrylate) (PMMA) on the melting and crystallization process of poly(ethylene oxide) (PEO) were studied under high pressures up to 500 MPa by d.t.a. The intensity of the X-ray diffraction peak of PEO in the sample crystallized at 500 MPa was compared with the intensity of the sample crystallized at 0.1 MPa. Melting point (Tm) depression of PEO observed at 0.1 MPa with decreasing PEO in the mixture was almost constant up to 500 M Pa. The depression rate of the crystallization temperature ( T c) of PEO with PMMA content decreased at elevated pressures up to 500 MPa. The intensity of the exothermic peak of crystallization of PEO in the d.t.a, curve of the sample of medium PEO content increased with pressure. The intensity of the wide-angle X-ray diffraction line of PEO in the sample crystallized at 500 MPa was larger than that of the sample crystallized at 0.1 MPa. Optical microscopic observation of the high pressure crystallized lower PEO content blend showed partial spherulite formation, indicating increased crystallizability at elevated pressure.
Посилання на статтю:
Crystallization of poly(ethylene oxide) in a mixture with poly (methyl methacrylate) under high pressure / C. Nakafuku and N. Toyonaga // Polymer. – 1992. – Vol 33. – P. 2370-2375.