Wybrane wlasciwosci geometrycznej struktury powierzchni wytworow porowatych otrzymanych z polietylenu

Abstract

The conditions were found in which the cellular topcoats of energetic and installation cables, fulfilling exploitation requirements (as for cables of trademark "OWY 3 x 1.5mm2 450/750 V"), were obtained by foam extrusion (Fig. 1, 2, 4 and 5). The topcoats were made of two commercial grades of PE-HD polyethylene, produced by Borealis (Table 1). Polyethylene was mixed with blowing agent "Hydrocel 530" in amounts up to 1 wt. %. The effects of blowing agent content on mean density, porosity degree (Table 2) and the roughness parameters of the surface were evaluated. Roughness parameters studied were as follows: mean arithmetic deviation of surface roughness profile (Ra), ten-point height of irregularities (Rz), maximum peak to valley height (Rm) and mean spacing of irregularities (Sm) (Table 3 and 4). Dependence of (Ra) and (Rz) on blowing agent content has been described with regression equations (Table 5). The values of correlation factors obtained (rkw>0.985) confirmed the good agreement of selected mathematical model with experimental data.