The Study Of The Structure And Impact Resistance Of Multilayer UHMWPE Composites

In this thesis,three new types of ultra-high molecular weight polyethylene(UHMWPE)materials(A film,B film and UD)are taken as the research object.By comparing and analyzing the properties and impact resistance mechanisms of UHMWPE materials,the optimized process for preparing multilayer UHMWPE composites is obtained.The mechanical properties and impact resistance of the prepared composites are systematically studied.The following research results were obtained.The laminated sheets of the above three UHMWPE materials were prepared by the direct lamination method,and their V50 value,SEA and depression depth were measured by standard impact test methods.The impact resistance mechanisms of them were studied by observing impact point morphology of each laminated sheet after impact,and found that the V50 value of B film is 666.0 m/s,which has better shear failure resistance,this is due to its higher viscosity average molecular weight(5.04 million),higher tensile breaking strength(2.8GPa)and higher tensile modulus(135.4GPa).The V50 value of the UD is 559.6m/s,which has better tensile strength,this is due to its higher crystallinity(88.67%)and greater tensile elongation at break(3.3%).The mechanism analysis of material found that the impact surface layer of the laminated sheet is shear failure deformation,the middle surface layer has both shear failure deformation and tensile failure deformation,and the back surface layer is tensile failure deformation.The B film and UD can be mixed reasonably according to the failure mechanism of the laminated sheet to further improve the impact resistance.According to the failure mechanism of the laminated sheet and the basic properties of the UHMWPE materials,the material structure design was carried out.Three hybrid UHMWPE composites(laminates)were prepared by the hot pressing method.It was found that the B film was placed on the impact surface layer and the back surface layer,and the UD was placed in the middle surface layer,the V50 value is higher(>720m/s),and the depression depth after impact is smaller(<13.0mm).