Accession Number : ADA549935


Title :   Effect of Nanoparticles on the Dielectric Properties of Polyimide


Descriptive Note : Journal articcle


Corporate Author : NAVAL ACADEMY ANNAPOLIS MD DEPT OF PHYSICS


Personal Author(s) : Bestaoui-Spurr, Naima ; Edmondson, C A ; Wintersgill, M C ; Fontanella, J J ; Adams, Todd


Full Text : http://www.dtic.mil/dtic/tr/fulltext/u2/a549935.pdf


Report Date : 30 Aug 2011


Pagination or Media Count : 11


Abstract : As part of a search for a better dielectric for use in high energy density capacitors, polyimide (PI) films containing a layered material, zirconium orthophosphate, ZrO(H2PO4)2*xH2O (alpha-ZrP), were fabricated. PI has the advantage that it can be used to very high temperatures. To characterize the materials, x-ray diffraction (XRD), differential scanning calorimetry (DSC) thermogravimetric analysis (TGA), and dielectric measurements (permittivity, loss and breakdown strength) were made. The permittivity and loss studies were also carried out on both neat PI films and alpha-ZrP. The XRD, DSC and TGA results are consistent with amorphous composites. The effects of water or other impurities were observed in all three kinds of dielectric studies on all three types of material. For example, the relative permittivity of the composites decreased strongly when water was removed from the materials. Nonetheless, some increase in the relative permittivity of the dry nanocomposites was observed. Impurity or water-associated loss peaks were observed in all three types of material. The frequency and temperature dependences of the loss peaks made it possible to identify which were true relaxations. The effect of water is to decrease the dielectric strength of the composites. However, in both the wet and dry materials, the dielectric strength exhibits a maximum at a loading of about 5 wt% alpha-ZrP.


Descriptors :   *DIELECTRIC PROPERTIES , *DIFFERENTIAL SCANNING CALORIMETRY , *POLYIMIDE RESINS , *X RAY DIFFRACTION , *ZIRCONIUM , AMORPHOUS MATERIALS , COMPOSITE MATERIALS , DIELECTRIC STRENGTH , DRY MATERIALS , ENERGY DENSITY , FILMS , IMPURITIES , THERMOGRAVIMETRIC ANALYSIS


Subject Categories : Plastics
      Electricity and Magnetism
      Thermodynamics


Distribution Statement : APPROVED FOR PUBLIC RELEASE