EFFECT OF DRAWING AND ANNEALING ON ELECTRICAL-CONDUCTIVITY IN LINEAR-POLYETHYLENE

Assuming a relation j(t)=j0 exp(— μEt/d) between the ionic conducting current j(t) and time t, the dependence of parameters μ (ion mobility), n0 (number density of ions) and σ0 (initial electrical conductivity) on the drawing and annealing was studied for linear-polyethylene films, where j0=n0qμE (=σ0E), E, applied electric field; d, thickness of sample, and q, electric charge of an ion. Under an assumption that polymer consists of conducting units with anisotropic ion mobilities μ11, μ22, and μ88 in three orthogonal directions, the relationship between ion mobilities and the orientation function f of the conducting units was derived theoretically. The theoretical analysis of data for drawn samples showed that the ion mobility parallel in the molecular chain direction was about 2.4 times as larger as that in the perpendicular direction, but after annealing this anisotropy disappeared. This change in the mobility caused by drawing and annealing is considered to be caused by the change of the aggregation in amorphous region which plays an important role for the ionic conduction. © 1978, The Society of Polymer Science, Japan. All rights reserved.