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SynopsisIn this paper, the electrical properties and the conductive mechanism of polymer-filler particles are discussed using polymer-grafted carbon black. Resistors with resistivities in the range of ca. 10-108 fi cm were made, and the resistancetemperature relationship was measured between 77 and 298" K. In this temperature range, the resistance decreased with an increase of temperature, suggesting that the electrical conduction is thermally activated. The resistance as a function of field strength was measured by a pulse method. The resistor was a resistivity of ca. 104 fi cm showed field dependence, and the change of resistance was reversible. It was found that the resistance was independent of temperature at high field strength, and tunneling conduction is predominant. On the basis of these facts, theoretical equations were derived and compared with the experimental values.

Section: Introductionmentioning

confidence: 99%

The conduction mechanism of polymer–filler particles

Miyauchi¹,

Togashi²

1985

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The hall effect measurement of the polymer–filler composition

Miyauchi¹,

Togashi²,

Sorimachi³

et al. 1986

The authors have studied the electrical conduction mechanism of polymer-filler particles using polymer-grafted carbon blackIn the previous paper,' it has been demonstrated that the electrical conduction is due to thermally activated electron hopping at low field strength, while tunneling conduction is predominant at high field strength. It is also important to know the number density of charge carriers and their mobility. But, for composite materials, these values have not still been measured accurately, because conductive fillers in conductive composite materials are liable to shift one another due to electrical field or magnetic field.Conductive materials made from GC are comparatively stable even at high electrical field or high magnetic field.' In this note, we present measurements of the Hall coefficient and resistivity, from which the number density of charge carriers as well as their mobility were determined.The GC samples were prepared according to the procedure described previously. 1.2 The preparation conditions of both GC and resistors are given in Tables I and 11, respectively. The shape of samples for the Hall effect measurements is shown in Figure 1. The resistivities were measured between the point a and the point b with a digital multimeter (Takeda Riken Industrial Co., Ltd., TR 6853). To obtain the Hall voltage, a given current was flown into the sample with a electric source (Metronix Model 691 A), and, at the same time, a given magnetic field was applied at right angle to the direction of the current. Then, the Hall voltage between point c and point d was recorded.The current take off in the sample was also determined from the voltage between point a and point b using the resistance between the two points. The Hall voltages of the samples TI-T,

Grafting of poly(α‐chloroacrylonitrile) (α‐PCIAN) on carbon black and electrical properties of α‐PCIAN‐grafted carbon black compositions

Miyauchi

Mino

Balard

et al. 1988

SynopsisThe electrical properties of poly( a-chloroacrylonitrile) (PClAN) carbon black compositions were determined. These materials were prepared by polymerizing a-chloroacrylonitrile in the presence of carbon black (GC resistors). Resistivities measurement of GC resistors shows a semiconductorlike behavior. Moreover, the resistance change of GC resistors with electrical field strength is very large. I t is concluded that the conduction of GC resistors is controlled by the thin polymer layer present at the surface of the carbon black particles. Heat degradation of such compositions was also investigated: A significant weight loss above 150°C is observed in all cases which can be attributed to thermal dehydrochlorination of PClAN. After heat treatment at 30O0C, during 1 h, the resistivities decrease of about 1 order of magnitude because of the formation of a semiconducting polyconjugated polymer by dehydrochlorination of PCIAN. EXPERIMENTAL Materials and ReagentsThe carbon black used was Cabot XC 42 (BET specific surface area = 210 m2/g., geometrical specific surface area = 111 m2/g). a-Chloroacrylonitrile (99%) was purchased from EGA-Chemie Co.