Dielectric response and breakdown strength improvement of LDPE/TiO2 nanocomposites by using POSS as compatibilizing agent
In this paper, two types of nanocomposites were prepared by ball milling techniquee The first type consists of 5% untreated titanium dioxide (TiO2) incorporated into LDPE. For the second one, 5% commercial TiO2 chemically treated with trisilanol phenyl polyhedral oligomeric silsesquioxane (TSP-POSS) as dispersant was ball-milled with LDPE. The microscopic observation by Atomic Force Microscopy (AFM) showed a better dispersion into polymer matrix of the TiO2 treated with POSS as compared to untreated TiO2. It was found that LDPE/treated TiO2 nanocomposite exhibited lower relative permittivity and dielectric losses compared to LDPE/untreated TiO2. The surface treatment of LDPE/TiO2 by TSP-POSS also affects the dielectric strength. The LDPE/treated TiO2 revealed highest breakdown strength of 82 kV/mm, compared to 78 kV/mm and 71 kV/mm of LDPE neat and LDPE/untreated TiO2, respectively.
Properties of polyethylene-layered silicate nanocomposites prepared by melt intercalation with a PP-g-MA compatibilizer
Abstract Polyethylene (PE)/clay nanocomposites were synthesized by melt-intercalation using either PP-g-MA or PE-g-MA as a compatibilizer. The pristine clay was first modified with a swelling agent (octadecylamine) in solution to obtain an organophilic clay before being melt blended with a compatibilizer: PP-g-MA or PE-g-MA. Finally, these compounds were melt intercalated with PE to synthesis the PE/clay nanocomposite. The materials were characterized using X-RD, TEM, SEM, and TGA. The physical properties were observed with DMA and tension tests. Permeability tests of the PE/clay nanocomposites were also performed. The clays in PE/clay nanocomposites with the compatibilizer PP-g-MA were better exfoliated. The mechanical and gas barrier properties improved as the clay content increased.
Effect of compound technology on polyethylene/ montmorillonite composites
The dielectric properties of nanometric dielectrics have attracted much attention since John Lewis published the article; the title is “Nanometric Dielectrics”, on IEEE transactions on dielectric and electrical insulation in 1994. However, the majority of works reported in the literature were involved in comparing the dielectric properties of polymer/inorganic nano-particles composites those of with polymer/inorganic micro-particles composites, and investigation on dielectric properties of polymer layered silicate (PLS) nano-composites, which exhibit excellent thermal and mechanical properties, were rarely found to be reported. The paper investigates the effect of dielectric property of nano-montmorillonite transnature polyethylene (PE), the polyethylene/montmorillonite (PE/MMT) nano-composites are prepared by melting intercalation process. The dielectric properties of the nano-composites are investigated, and then the space charge profile in PE/MMT and PE is measured by pulsed electro-acoustic (PEA) method respectively. The test results indicate that the involvement of nano-MMT can decrease the amount of space charge in dielectric The AC breakdown strength can be enhanced.