| 초록 |
It is well known that the crystallinity and the melting temperature of polyethylene are reduced while the fracture stress increases substantially by incorporation of a small amount of short chain branches. However, microstructure-property relationships of ethylene copolymers are not understood. Therefore, we studied the structural variations of ethylene copolymers as a function of the branch type and contents by carrying out time- and temperature-dependent small angle x-ray scattering experiments. Our results show that during the isothermal crystallization and subsequent heating towards melting the copolymer samples show a well-defined lamellar thickness, which does not change with time. In comparison, the lamellar thickness increase with time for homopolymer. On the other hand, the noncrystalline layer thickness does not shows definite values for copolymers whereas the homopolymer shows well-defined values which do not change with time. |
