Study On Rheological Behavior Of Shear Thickening Liquid And Design And Preparation Of Multi-Component Composite Damping Material

Shear thickening liquid can be used as a liquid protective material,but it has many problems of inconvenient use and unstable protective performance due to its fluidity.In this paper,the effect of surface modification of shearing thickening on the shear thickening properties of the constituent monomer silica nanoparticles was studied.A new type of shear thickening gel material was proposed:in the static state.There is no fluidity,and the shearing becomes thin under low-speed shearing and exhibits fluidity,and it can quickly thicken and protect against high-speed shearing.Specifically,the supramolecular self-assembly is combined with the shear thickening liquid phase to construct a supramolecular assembly shear thickening gel system.The effect of small molecule gelatin on the shear thickening performance of shear thickening liquid and the rheological behavior of shear thickening gel system were studied.Secondly,the shearing thickening liquid and elastic waterborne polyurethane composite shear were studied.The thickening phenomenon and mechanical properties were cut.Finally,the mechanical properties and protective properties of Kevlar fibers with shear thickening solution were studied.The main results of this paper are as follows:1.Prepare silica NP with various surface chemical compositions and use it to prepare dense suspension.Rheological experiments were carried out to determine the effect of NP interaction on the corresponding dense suspension system.The influence of the interaction between particles of clay behavior,including the surface modification of silica described NPs initial shear thickening sigma onset of stress,the critical points for?_C and jamming volume fraction?_J.Friction contact(or gravity)due to mutual attraction between NPs is a prerequisite for achieving shear thickening.From continuous shear thickening CST to the transition of discontinuous shear thickening DST's critical points for?_Cchanges are as follows:heat treatment,the amino modified and unmodified NPs?_C decreases in turn.The initial shear stress is negatively correlated with the repulsive force.2.The introduction of gelling factors largely affects the shear thickening properties of silica nanoparticle suspensions.The non-covalent interaction between small organic molecules immobilizes a large number of suspension molecules in their network structure,forming a supramolecular shear thickening gel system.The interaction between the gelling factors causes the shear viscosity of the suspension to be higher than the shear viscosity of the conventional suspension.The shear thickening gel has a yield shear stress that changes from a gel state to a sol state.When the yield stress of the shear thickening gel is less than the critical shear stress,the shear thickening gel first undergoes shear thinning.When the gel state changes to the sol state,the critical shear stress is reached,so shear thickening can occur;when the yield stress is greater than the critical shear stress,the shear thickening gel has reached the critical point before reaching the yield stress.Shear stress,at which point the suspension is still in a gel state,so the suspension does not undergo shear thickening.3.The shear thickening of the composite material of the shear thickening fluid occurs under stress.The increase in the content of the shear thickening liquid enhances the resistance of the composite sample to compression,and the composite sample having the same displacement as the shear thickening liquid has a greater force.In addition,as the compression speed increases,the shear rate also increases,and the composite exhibits a more pronounced shear thickening.The combination of the shear thickening liquid and the polyurethane combines the properties of the two,so that it not only has the shear thickening property of the shear thickening liquid but also has good elastic properties of the polyurethane.Samples with more shear-enriched liquid content exhibited better shear thickening performance,and samples with more polyurethane content exhibited better elastic properties.4.In the composite material of Kevlar fiber,the shear thickening liquid adheres to the fiber,provides shear stress when tensile force acts,and shear thickening occurs,which increases the interaction force between the fibers.There is a phenomenon that the tensile force increases instantaneously.At the same time,the appearance of clusters of particles in the shear thickening liquid forms a cluster of particles on the surface of the fiber,which increases the friction between the fibers.The composite of polyurethane and shear thickening liquid increases the shear thickening liquid attached to the fiber surface,the protrusions formed by the particle clusters increase,the fibers bond to each other,and the interaction force further increases,which enhances the composite material.The penetration resistance provides a reliable research basis for the investigation of the protective properties of composite materials.By studying the shear thickening of silica nanoparticle suspension,the preparation of supramolecular assembly shear thickening gel was completed and its performance was studied.The mechanical properties and protective properties of the composite materials of suspension and Kevlar fiber were further elaborated,which provided a theoretical basis and reliable basis for the development of liquid body armor.