| Abstract: | The change of long spacing in polyethylene and nylon-6 during heating at 18°C/min. was measured with an apparatus devised for rapid measurement of the small-angle x-ray diffraction. The apparatus made it possible to obtain a diffraction profile in 1.8 sec. Long spacings increased notably at high temperatures near the melting point, as has been observed during low-rate heating. However, the increase in long spacing during heating was very small in a methoxymethylated nylon-6 sample. This suggests that the increase in the long spacing at high temperature is due to the thickening of crystals. The long spacing in polyethylene samples in the vicinity of the melting point is apparently independent of thermal history. |
