To reduce weight and increase mobility, comfort, and performance of future spacesuits, flexible, thermally conductive fabrics and plastic tubes are needed for the Liquid Cooling and Ventilation Garment. Such improvements would allow astronauts to operate more efficiently and safely for extended extravehicular activities. As an approach to raise the thermal conductivity (TC) of an ethylene vinyl acetate copolymer (Elvax 260), it was compounded with three types of carbon based nanofillers: multi-walled carbon nanotubes (MWCNTs), vapor grown carbon nanofibers (CNFs), and expanded graphite (EG). In addition, other nanofillers including metallized CNFs, nickel nanostrands, boron nitride, and powdered aluminum were also compounded with Elvax 260 in the melt at various loading levels. In an attempt to improve compatibility between nanofillers and Elvax 260, MWCNTs and EG were modified by surface coating and through noncovalent and covalent attachment of alkyl groups. Ribbons of nanocomposites were extruded to form samples in which the nanofillers were aligned in the flow direction. Samples were also fabricated by compression molding to yield nanocomposites in which the nanofillers were randomly oriented. Mechanical properties and degree of dispersion of aligned samples were determined. TC was measured in the direction of, and perpendicular to, alignment. Additionally, tubing was extruded from select nanocomposite compositions and TC and mechanical flexibility measured. MWCNTs and EG 3775 surfaces were modified with aliphatic groups through electrostatic and covalent attachment. Electrostatic attachment was accomplished with 1-dodecylbromide and generally resulted in less than 0.2 wt % loading. An approximate order of magnitude increase in loading was observed with the covalent attachment of 1-dodecylamine. The highest TC for randomly oriented samples was exhibited by 50 wt % modified (covalent) EG (7.6-fold increase). Again, noncovalently modified MWCNT samples showed higher TC values compared to unmodified ones while the opposite was observed for modified EG samples. TC results from LMM samples showed conclusively that nanofiller alignment in the polymer matrix significantly raised TC. However, unaligned samples also showed a significant improvement and may be useful in applications when it is not possible to achieve nanoparticle alignment. Alkyl-modified nanofiliers yielded a significant improvement in flexibility as seen in the cases of the 20 wt % modified (electrostatic) MWCNT and the 40 wt % modified (electrostatic) EG. When 20 and 30 wt % modified (covalent) EG samples were tested, they exhibited greater flexibility compared to their unmodified counterparts. In all cases modification (covalent or electrostatic) improved the flexibility but the effect on the TC varied. It was possible that the alkyl groups provided a plasticizing effect.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Thermal conductivity of ethylene vinyl acetate copolymer/nanofiller blends


    Additional title:

    Die Wärmeleitfähigkeit von Mischungen von Ethylen-Vinylacetat-Copolymer mit Nanofüllstoffen


    Contributors:


    Publication date :

    2007


    Size :

    18 Seiten, 9 Bilder, 5 Tabellen, 45 Quellen


    Remarks:

    (Paper 5)



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Thermal conductivity of ethylene vinyl acetate copolymer/carbon nanofiller blends

    Ghose, S. / Watson, K.A. / Working, D.C. et al. | British Library Conference Proceedings | 2007





    TIRE WITH ETHYLENE-VINYL ALCOHOL COPOLYMER INNERLINER

    CHANDRA DINESH / GILLICK JAMES GREGORY | European Patent Office | 2022

    Free access