Title :
Dielectric Properties and Crystalline Morphology of Low Density Polyethylene Blended with Metallocene Catalyzed Polyethylene
Author :
Wang, X. ; He, H.Q. ; Tu, D.M. ; Lei, C. ; Du, Q.G.
Author_Institution :
Xi´´an Jiaotong Univ., Xi´´an
fDate :
4/1/2008 12:00:00 AM
Abstract :
Dielectric properties of low-density polyethylene (LDPE) blended with metallocene catalyzed polyethylene (MPE) to 1, 3, 5 wt% of the latter are reported. It was found that the 1 wt% MPE blend had the lowest volume resistivity, the highest direct current (DC) breakdown strength and the least accumulated space charge. The crystalline morphology of the blends was studied through differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and small-angle light scattering (SALS) measurements. It was found that blending increased the percentage crystallinity, decreased the spherulite size and caused the formation of imperfect spherulites, i.e. spherulites containing defects and impurities in their crystalline phases, and thus fewer impurities and defects on their boundaries. The improvement in dielectric properties of the blends, especially the 1 wt% MPE blend, is attributed to the increase in crystallinity and the formation of imperfect spherulites.
Keywords :
X-ray diffraction; crystal defects; crystal morphology; dielectric materials; differential scanning calorimetry; electric breakdown; light scattering; polymers; space charge; DSC; SALS; WAXD; accumulated space charge; crystalline morphology; dielectric properties; differential scanning calorimetry; direct current breakdown strength; low-density polyethylene; metallocene catalyzed polyethylene; small-angle light scattering; spherulite size; volume resistivity; wide-angle X-ray diffraction; Calorimetry; Conductivity; Crystallization; Dielectrics; Electric breakdown; Impurities; Morphology; Polyethylene; Space charge; X-ray diffraction;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
DOI :
10.1109/TDEI.2008.4483448