Abstract
The polymers containing furnace black grafted with n-butyl acrylate or acrylic acid were cured with a peroxide (di-t-butyl peroxide, cummene hydroperoxide or di-cumyl peroxide) and a divinyl monomer (ethylene dimethacrylate), and their degree of crosslinking was determined by the measurement of gel fraction. Di-cumyl peroxide-ethylene dimethacrylate system was found to show the highest crosslinking efficiency. Then, the resistors were made from the polymers with different degrees of crosslinking by coating the carbon black-graft polymers dispersed in acetone on porcelain plates and heating them at 150°C for 5hr., and their electric resistance were measured.
The following results were obtained:
(1) The volume resistivity was in the range of 6∼8Ωcm.
(2) The temperature coefficient was nearly equal to zero, regardless of the degree of crosslinking.
(3) The hysteresis of resistance against temperature was smaller than that of the resistors made from the polymers crosslinked with epoxy resin and it decreased with increasing crosslinking.
