Surface free energy of extruded polymer compositions

Suitable adhesive properties of the polymer compositions provide largely outer surface of the product. The aim of the studies was evaluation of the efficiency of the extrusion process and physical properties of PVC modified by selected auxiliary. In the studies PVC was used. PVC was modified by blowing agent (0-1.5% by mass) and antistatic agent (0-0.8% by mass) in the form of polyvinyl chloride concentrates. Efficiency of extrusion process is determined also by selected proprieties of surface layer of a mill cake of polyvinyl chloride. Surface free energy has been calculated in Owens-Wendt method. Antistatic agent causes diminishing of wettability and adsorption of surface layer and eventually increase of surface free energy of surface layer. For ensuring appropriate adhesion properties of a surface layer it would be advisable to use, for polyvinyl chloride modification, the antistatic agent in the amount not smaller than 0.4% by mass in relation to polyvinyl chloride mass. Taking into account research results, which can be useful during the development of processing technology of the polyvinyl chloride used for polymers composites, it can be stated that the content of the blowing agent used, noticeably decreasing polymer mass and simultaneously not worsening the properties of a surface layer, should not exceed 0.5÷1.0% by mass in relation to polyvinyl chloride mass.