Effect of selected auxiliary agents on the properties of surface layer of extruded polyethylene

The effect of modification of medium density polyethylene (PE-MD), widely used for optotelecommunication cables coatings, with selected auxiliary agents on the properties of surface layer of stampings has been investigated. Blowing agent (SP) and antistatic agent (SA) were used as modifiers. Wetting angle (theta) and free surface energy (gamma(s)) were determined by Owens-Wendt's method [equation (1)-(3)]. Significant effects of SP and SA contents on the properties investigated were observed (Table 2, Figs. 1-3). It was found that gamma(s) decreases monotonically and nonlinearly with increasing SA content what meets wettability decrease. On the contrary, an increase in SP content causes increase in gamma(s)s so also wettability increase. Adsorbed SA quantity does not increase linearly with an increase in its content in PE-MD but slowly asymptotically approaches the limiting saturation. Additionally, on the basis of gamma(s) mean values, the systems of regression equations, describing the dependences between gamma(s) and SA or SP contents, were determined (Table 3).