Time dependence of the complex heat capacity at the melting temperature ofpolyethylene crystals

Time dependence of the complex heat capacity of polyethylene crystals was m easured at several temperatures between 80 and 130 degreesC using light hea ting modulated temperature DSC. Time dependence could be expressed as a sum of fast and slow components. The fast component had the complex value and decayed within a few minutes. On the other hand, the slow component had the real value and decreased much more slowly towards a finite value. The fast and slow components were attributed to melting and ordering of the crystal , respectively. Time dependence was significant at temperatures in the melt ing peak of the total heat flow (123 degreesC and higher). However, even at the lowest temperature very small fast component was observed. This sugges ted that a very small amount of the crystal melted at this temperature. (C) 2001 Elsevier Science B.V. All rights reserved.