Correlation between breakdown and structure of low-density polyethylene using metallocene catalyst in gas phase

摘要

In order to investigate the influence of different morphology on electrical properties, we used four kinds of low-density polyethylenes using metallocene catalyst (mL-LDPE) in gas phase. For these specimens, we estimated the crystal structure by using X-Ray Diffraction pattern. It was found that mL-LDPE with a higher density has larger crystal size of (110) and (200) plane and lower amorphous halo ratio than mL-LDPE with a lower density. At 30°C and 60°C, the impulse breakdown strength of mL-LDPE increases with the increase of density. At 90°C, on the other hand, mL-LDPE shows almost same breakdown strength in spite of the difference of density. The density dependence of impulse breakdown strength became weaker with decrease of its density. The breakdown of mL-LDPE is suggested to occur in amorphous regions. From the results, we estimated the correlation impulse breakdown and structure of mL-LDPE.