AC Performance,Physical And Mechanical Properties Of Polypropylene/Polyolefin Elastomers Blends

For its stable chemical properties,strong resistance to tensile strength,excellent dielectric characteristics,high breakdown strength and other excellent physical and chemical properties,polypropylene has widely applied in various fields.But with the demand of polypropylene increasing,the high brittle temperature,poor toughness and the high forming shrinkage rate defects are also drawing more and more attention,these shortcomings were severely limits the application in the field of high voltage insulation of polypropylene resin,research on toughening modification of polypropylene materials has become a hot topic.Polypropylene of toughening modification can be widely used in high voltage cable industry,has broad development prospects.Thermoplastic elastomers,also referred to as artificial or synthetic rubber.When under room temperature,it will show properties similar with rubber-like elastic;under high temperature conditions,it will show the plasticity of plastic molding a class of elastomeric material.In this paper,polypropylene/elastomer blend materials with different content of elastomer are prepared by blending polypropylene and ethylene/octene copolymer elastomers(POE),polypropylene and styrene-ethylene / butylene-styrene triblock copolymer(SEBS).We test the properties of the blends by SEM ? DSC ? mechanical performance? DMA ? breakdown performance etc.,to investigate the micro morphology?crystallization properties,AC breakdown strength and mechanical properties of PP and blends.It is found that PP and elastomer present "island structure",and with the increase of the elastomer content in the system,the size and the concentration of island increase accordingly.When the elastomer reaches 30wt%,the size of island increased significantly.With the same proportion of the elastomer,the island phase size of SEBS is lower than that of POEs;with the increase of elastomer,the crystallinity decreases slightly,but the crystallization temperature and melting temperature of the system do not show significant changes.The heat extension of blends is only 11% at 165?.Yield tensile test indicates that the yield stress of the composite decreases to about 20 Mpa.The incorporation of SEBS makes the elastic modulus of PP at room temperature reduce to about 750 Mpa.The breakdown strength of the composites is generally lower than that of PP,but the composite with 25wt% SEBS almost keep the breakdown performance of pure PP.The "island structure" in PP/elastomer blends retains the mechanical strength of PP,reduces significantly the hardness material and increases the toughness and flexibility of PP at the same time.