Silicone powder modified ultra-high molecular weight polyethylene and its melt-spinning processability
To improve the fluidity of ultra-high molecular weight polyethylene(PE-UHMW)during melt processing,silicone powder was applied and a melt blending method was adopted.The distribution of silicone powder in PE-UHMW was characterized by scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS),and the influence of silicone powder content on the melt flow rate(MFR)and rheological properties of PE-UHMW was analyzed using melt rate testing and rotational rheological testing.Modified PE-UHMW monofilaments were prepared by the melt spinning method,and the tensile strengths were tested.The SEM and EDS results showed that with the increase of silicone powder,its dispersibility gradually deteriorates.The flow rate of PE-UHMW melt first increases and then decreases with the increase of silicone powder content.When the mass fraction of silicone powder reaches 4%,its MFR is the highest,and its complex viscosity and storage modulus are the lowest.The aggregation of 5%mass fraction silicone powder in the PE-UHMW matrix is more obvious,and the MFR of modified PE-UHMW melt decreases.The results of melt spinning experiments indicate that the modified PE-UHMW can be extruded into as-spun filament using a convention-al single screw extruder,and high-strength monofilaments can be prepared by hot drawing.When the draw ratio is 36,the highest tensile strength of PE-UHMW monofilament modified with 3 wt%silicone powder can reach 1 565 MPa.Therefore,considering both processing performance and strength,it is more appropriate to use 3 wt%silicone powder to modify PE-UHMW.
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