Study On Toughening Of Ultra High Molecular Weight Polyethylene Composite Yarn And Its Fabric Protective Properties

Ultra-high molecular weight polyethylene?UHMWPE?fibers have higher specific strength and specific modulus,lower elongation at break,and higher crystallinity.They are widely used in defense,military,aerospace and other fields.One of the more high-performance fibers used in the impact field,but due to the inertness and smoothness of the UHMWPE fiber surface,the UHMWPE bundle fiber is prone to loosening,fluffing and other phenomena during the weaving process.At the same time,the UHMWPE fabric is directly compounded with the resin,which easily causes the phenomenon of uneven wetting of some fiber resins.In this project,yarns are twisted,wrapped,and heat treated.At the same time,polyurethane is used as a coating material to directly coat UHMWPE fiber bundles at the yarn level,and the mechanical and thermal properties of these yarns are characterized.Finally,two sets of yarns with excellent mechanical properties were selected for subsequent 2.5D weaving to investigate the performance differences between twisted yarns and polyurethane-coated yarn fabrics in the areas of puncture resistance,cut resistance and impact resistance.The main findings are as follows:?1?By changing the twisting and wrapping process and heat treatment temperature,the appearance,morphology,mechanical and thermal properties of UHMWPE twisted and wrapped yarns were characterized,and the optimal heat treatment temperature of UHMWPE yarns was obtained.The twisting method and the mechanical properties of the twisted yarn were analyzed to obtain the twisted yarn with the best tensile mechanical properties.Among the three heat setting temperatures?60?,90?,120??selected in the experiment,60? heat setting effect is the best.At this temperature,the yarn has a good setting effect,and with the change of twist,the yarn The mechanical properties also remain excellent.UHMWPE yarns twisted at room temperature with a twist of 250 T / m have the best tensile strength of 60.67 ± 7.55 N,a 17.24% increase in strength over UHMWPE fibril bundles,and the wrapping treatment can significantly improve the yarn Stretching strength.?2?The differences in micro-morphology,mechanical properties,thermal properties,and interface properties of polyurethane composite yarns prepared from DMF solvent system and DMF / Toluene solvent system were explored,and the linear density and appearance of polyurethane composite yarn were explored.The appearance,tensile strength,thermal stability and interfacial shear strength change with the nano-ZrO₂ solid content in the polyurethane coating.It was found that the tensile strength and interfacial shear strength of the coated yarn prepared by the DMF / Toluene solvent system were higher than those of the DMF solvent system coated yarn,and the addition of nano-ZrO₂ in polyurethane had mechanical properties,thermal stability and interfacial properties of UHMWPE yarns.Both have the effect of improving.In the DMF / Toluene solvent system,the composite yarn with a solid content of 3.23% on the surface of the UHMWPE fiber has the largest tensile strength value.Its primary tensile strength is 162.13 ± 8.99 N,compared with UHMWPE fibril The increment of the beam is 213.29%.?3?Exploring the weaving process of UHMWPE twisted yarn and polyurethane-coated yarn weaving layers of orthogonal angle interlocking fabrics,and comparing the density,stab resistance,cut resistance and impact resistance of twisted and coated yarn fabrics And other performance differences,explore the changes in these properties with the increase of the number of fabric weft layers.The study found that the anti-puncture performance,cut-proof performance,and maximum impact resistance of the coated yarn layer orthogonal angle interlocking fabric were higher than those of the twisted yarn fabric.The areal density,maximum puncture force,maximum sliding cutting distance,and maximum impact load of twisted and coated yarn fabrics are all positively related to the number of fabric layers.The maximum impact load of 1-layer,3-layer,and 5-layer coated yarn fabrics was 11.70%,24.55%,and 4.88% over the twisted yarn fabrics of the same number of layers.