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Positive temperature coefficient to resistively characteristics of polystyrene/nickel powder/multiwall carbon nanotubes composites
Author(s) -
Kar Prativa,
Maiti Sandip,
Shrivastava Nilesh K.,
Dhibar Saptarshi,
Khatua B.B.
Publication year - 2012
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.22338
Subject(s) - materials science , composite material , polystyrene , carbon nanotube , thermal stability , thermogravimetric analysis , temperature coefficient , dynamic mechanical analysis , glass transition , carbon black , electrical resistivity and conductivity , thermal expansion , dielectric , polymer , chemical engineering , natural rubber , electrical engineering , optoelectronics , engineering
Positive temperature coefficient to resistivity (PTCR) characteristics of polystyrene (PS)/Ni‐powder (40 wt%) composites in the presence of multiwall carbon nanotubes (MWCNTs) has been investigated with reference to PS/carbon black (CB) composites. The PS/CB (10 wt%) composites showed a sudden rise in resistivity (PTC trip) at ≈110°C, above the glass transition temperature ( T g ) of PS (T g ≈95°C). Interestingly, the PTC trip temperature of PS/Ni‐powder (40 wt%)/MWCNT (0.75 phr) composites appeared at ≈90°C (below T g of PS), indicating better dimensional stability of the composites at PTC trip temperature. The PTC trip temperature of the composites below the T g of matrix polymer (PS) has been explained in terms of higher coefficient of thermal expansion (CTE) value of PS than Ni that led to a disruption in continuous network structure of Ni even below the T g of PS. The dielectric study of PS/Ni‐powder (40 wt%)/MWCNT (0.75 phr) composites indicated possible use of the PTC composites as dielectric material. Dynamic mechanical analysis (DMA) and thermogravimetric analysis studies revealed higher storage modulus and improved thermal stability of PS/Ni‐powder (40 wt%)/MWCNT (0.75 phr) composites than the PS/CB (10 wt%) composites. POLYM. COMPOS., 33:1977–1986, 2012. © 2012 Society of Plastics Engineers