Metallocene based polyolefin: a potential candidate for the replacement of flexible poly (vinyl chloride) in the medical field

A comparative assessment of the performance properties of metallocene polyolefin (m‐PO) with those of plasticized poly (vinyl chloride) (pPVC) and ethylene vinyl acetate (EVA) copolymer having 18% vinyl acetate content (EVA‐18), the two common polymers used for flexible medical products, is carried out. The preliminary evaluation of the processability, mechanical properties, and thermal stability of the new material, m‐PO is described. The processability parameters like mixing torque and melt viscosity of m‐PO are found to be comparable with those of pPVC and EVA‐18. Mechanical properties such as tensile strength, elongation at break, and tear strength (TS) of m‐PO are much higher than that of pPVC and EVA‐18. Thermo gravimetric analysis (TGA) indicates that the thermal degradation of m‐PO takes place only at temperatures above 340°C and can be processed at 170°C without much damage. Oxygen and carbon dioxide permeabilities of m‐PO at three different temperatures (10, 25, and 40°C) are evaluated and compared with those of pPVC and EVA‐18. It could be seen that the permeabilities of both the gases for m‐PO at three temperatures were lower than those of pPVC and EVA. Biological evaluation of m‐PO is carried out by assessing its cytotoxicity, hemolytic property, and blood clotting initiation. The cytotoxicity studies indicate that m‐PO is non‐toxic to the monolayer of L929 mammalian fibroblast cell lines on direct contact or the exposure of its extract. Non‐hemolytic property of m‐PO by direct contact as well as test on extract is revealed both in static and in dynamic conditions. Blood clotting time experiments indicate that the initiation of blood clotting due to m‐PO is faster than that of pPVC and EVA‐18. Copyright © 2009 John Wiley & Sons, Ltd.