Investigation of multi-walled carbon nanotube-reinforced high-density polyethylene/carbon black nanocomposites using electrical, DSC and positron lifetime spectroscopy techniques

Jeevananda, T. and Kim, N. H. and Lee, J. H. and Basavarajaiah, S. and Deepa Urs, M. V. and Ranganathaiah, C. (2009) Investigation of multi-walled carbon nanotube-reinforced high-density polyethylene/carbon black nanocomposites using electrical, DSC and positron lifetime spectroscopy techniques. POLYMER INTERNATIONAL, 58 (7). pp. 775-780.

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Official URL: http://dx.doi.org/ 10.1002/pi.2591

Abstract

BACKGROUND: The positive temperature coefficient (PTC) effect on material properties has attracted much attention in recent years due to the prospects of many applications like temperature sensors, thermistors, self-regulating heaters, etc. It has been suggested that incorporation of multi-walled carbon nanotubes (MWNTs) into carbon black (CB)-filled polymers could improve the electrical properties of composites due to high conductivity and network structure and significantly reduce the required CB loading. RESULTS: We observed no change in melting temperature and crystalline transition temperature on addition of MWNTs. However, the heat of fusion decreases as the amount of conducting carboxylated MWNT (c-MWNT) filler increases and the resistivity of the composite decreases. The free volume shows an increase up to 1.5 wt% of c-MWNT content and then decreases. CONCLUSION: Well-developed crystals could not be formed due to restricted chain mobility as filler content increases. This results in minimum intermolecular interactions, and thus a decreased heat of fusion. A composite with c-MWNT content of 0.5 wt% showed the highest PTC and higher resistivity at 150 degrees C possibly due to the formation of flocculated structures at elevated temperature. For filler content greater than 1.5 wt%, the decrease in free volume may be due to restricted chain mobility. (C) 2009 Society of Chemical Industry

Item Type: Article
Uncontrolled Keywords: nanocomposite; high-density polyethylene; carbon nanotubes; positron annihilation; free volume holes
Subjects: Physical Sciences > Physics
Divisions: PG Campuses > Manasagangotri, Mysore > Physics
Depositing User: Users 1 not found.
Date Deposited: 01 Apr 2013 10:27
Last Modified: 16 Mar 2016 10:02
URI: http://eprints.uni-mysore.ac.in/id/eprint/2749

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