Use of mineral fillers in PVC plastics for insulating electrical conductors

Abstract

The use of fillers in plastics is closely related with the use that the different elaborated articles will have. In this work, formulations of PVC plastics were developed for insulating electrical conductors (cables and wires) using different mineral fillers (kaolin, volcanic glass and natural zeolites). The stability of the materials obtained was evaluated in an accelerated manner and through atmospheric exposure tests in the climatic conditions of three different test stations (rural, marine and industrial). The changes in the properties of the materials exposed to atmospheric aging were evaluated by means of physical-mechanical tests (tensile strength σ, and relative elongation ε), electrical tests (volumetric resistivity ρv and dielectric loss Tg d) and thermal tests (determination of the 5% loss of plasticizer). The behavior of each of the materials during five years of exposure to the elements was similar in the different test stations, and after three years of exposure, they do not meet the requirements of the standard for physical-mechanical properties. The samples corresponding to the formulations with the mineral loads studied, without any type of prior treatment (except kaolin), exposed indoors at the test stations (rural and marine) for seven years of exposure, did not experience practically any alteration in their dielectric and physical-mechanical properties. The incorporation of fillers in all cases improved the resistance to desorption of the plasticizer. The incorporation of the studied loads can be valued for their use in Cuba in the production of electrical insulators.