Abstract
The positive temperature coefficient (PTC) characteristics of polymer composites were investigated with the nano-sized carbon black particles using solution casting and melt compounding methods. The polymeric PTC composites showed the electrical threshold at 35 wt% for the melt compounding method and 40 wt% for the solution casting method. The ethylene vinylacetate copolymer (EVA) composite showed a gradual increase of resistance as a function of temperature and showed a maximum at the polymer melting point. The resistance of the high-density polyethylene (HDPE) composite remains unchanged with temperature but started to increase sharply near the melting point of HDPE and showed a maximum resistance at the melting point of HDPE. The dispersion of nano-sized carbon black particles was investigated by scanning electron microscopy (SEM) and low resistance after electrical threshold, and both methods exhibited a well dispersed morphology. When the electric current was applied to the PTC composites, the resistance started increasing at the curie temperature and further increased until the trip temperature was reached. Then the resistance remained stable over the trip temperature. The secondary increase started at Tm of matrix polymer and kept increasing up to the trip temperature.
| Original language | English |
|---|---|
| Pages (from-to) | 812-820 |
| Number of pages | 9 |
| Journal | Polymer (Korea) |
| Volume | 26 |
| Issue number | 6 |
| State | Published - Nov 2002 |
Keywords
- Curie temperature
- Dispersity
- Electrical resistance
- Nano-sized carbon black
- Positive temperature coefficient (PTC)
