Halloysite Nanotubes And Chitin Nanocrystals Reinforced Rubber Conductive Composites

One-dimensional nanomaterials such as nanocrystals,nanotubes,and nanofibers have superior properties such as large aspect ratio,high mechanical strength,large specific surface area,and good adsorption performance,which have important applications in composite materials.In this dissertation,two kinds of one-dimensional nanomaterials from the natural world,halloysite nanotubes?HNTs?and chitin nanocrystals?CNCs?,were selected and compounded with the rubber material to prepare performance rubber nanocomposites by the solution method.The preparation,structure and properties of the composites were systematically studied.Through the introduction of conductive components,new composite materials with good conductivity and strain sensing properties are prepared,which have potential application prospects in the field of high performance conductive rubber materials.?1?PPy-coated HNTs?PPy@HNTs?were prepared by in-situ polymerization using HNTs as a template,which were found to have good dispersion and stability in water.Furthermore,x SBR/PPy@HNTs conductive composites were prepared by solution mixing with carboxylated styrene-butadiene rubber latex?xSBR?.It was found that the addition of PPy@HNTs can give xSBR good electrical conductivity.When the filler content is 10%,the conductivity of the sample is 1.82×10^-4 S/m.FTIR and XRD results indicate that there is an interfacial interaction between PPy@HNTs and xSBR.The tensile strength of the composite was improved by adding PPy@HNTs.Thus,a class of rubber composites with high mechanical properties,good electrical conductivity,and low cost can be prepared,which can be used for piezoresistive sensors,polymer electrodes,and capacitors.?2?Uniform and stable dispersions of CNCs were prepared by acidolysis method and ultrasonic dispersion method.The liquid crystal behavior and sol-gel transition behavior of CNCs dispersions were studied by polarizing microscope?POM?and rheometer.It was found that the liquid crystal phase of the CNCs began to appear at a concentration of 5%,and CNCs could assemble into a liquid crystal state in an oil medium and maintain the liquid crystal structure when dried.The 10%concentration of CNCs dispersion exhibited sol-gel transition behavior.The nanocomposite membrane material was prepared by adding the aqueous dispersion of CNCs to natural rubber?NR?latex through solution mixing and casting drying.Tensile and tear tests show that CNCs can significantly increase the mechanical strength and modulus of NR,and the tensile strength of the composite material with 10%CNCs is 5.75 MPa,which is 6.25 times that of pure NR.Dynamic mechanical analysis results show that the storage modulus of NR/CNCs composites increases with the addition of CNCs.The addition of CNCs can improve the thermal stability of NR/CNCs composites.NR/CNCs composites have the advantages of simple preparation process,high mechanical performance and environmental friendliness,which have potential applications in the field of green high-performance elastic materials,and at the same time broaden the application fields of CNCs.?3?Using the good enhancement ability of CNCs and combine it with NR latex.The sandwich composite structure was formed by spraying NR/CNCs latex and conductive carbon black?CB?on the glass substrate by thermal spraying method.The NR/CNCs-CB conductive composites with spiral lamellar structure were successfully prepared by rolling up.It was found that CB can be tightly adhered to NR/CNCs matrix,and the conductive properties of the composite material are effectively controlled by controlling the thickness of the CB layer.A composite material with a CB content of 4.44%was used as a strain sensor and it was found that it can detect human physiological activities such as bending of the joint,nodding,opening mouth,open eyes and closed eyes.The composite material has good repeatability,and its stretching-releaseing curve almost coincides?n>1?during multiple stretch-release cycles.The kind of composite material has good conductivity,good stretchability,structure stability and the variable characteristics of the strain sensitivity,which make them as potential applications for wearable electronic products in monitoring human daily activities.