Construction And Performance Characterization Of Cnt-cellulose Composite Materials

The large consumption of non-renewable resources and the increasingly prominent environmental pollution problems make the development and utilization of green renewable resources the best choice.As the world’s most abundant natural polymer material,it is of great significance to make full use of cellulose.In this paper,three kinds of CNT-cellulose conductive composite materials were prepared by using cellulose as the matrix and carbon nanotubes as conductive fillers.Combined with the structures and properties of the composites,they were applied to electromagnetic interference shielding,liquid sensing and multi-function strain sensor materials.(1)The non-covalently modified and ultrasonically assisted dispersion of the CNT dispersion liquid and the NaOH/urea solution were mixed and used to dissolve the cellulose at a low temperature,and the obtained mixed solution was solidified and regenerated to obtain a CNT-cellulose conductive composite films.The CNTs were aggregated by the pressure in the longitudinal direction during the drying and dehydration of the composite membranes,and a unique carbon nanotube conductive layered network was formed in the cellulose matrix.Based on the conductivity of the CNTs network to the composite films and the CNTs conductive layered structure,the composite films have the characteristics of light weight,flexibility,high electrical conductivity,and also have excellent electromagnetic interference shielding efficiency(7678 dB·cm2 g-1),are the ideal,customizable and efficient EMI shielding materials.(2)The cellulose solution was spun into cellulose fibers by the wet spinning technique,and then the CNT-cellulose composite fibers were prepared by dip coating in the CNTs dispersion.Based on the hygroscopic swelling characteristics of the cellulose matrix on the liquid,the CNTs network structure on the fiber surface was changed,and then the change of the composite fiber resistance was reflected.Therefore,the accurate,sensitive,and stable liquid sensing capability of the CNT-cellulose composite fibers can be achieved by monitoring the resistance change.(3)CNT-cellulose/PDMS composite materials were prepared by CNT-cellulose composite fiber as the template and secondary recombination with polydimethylsiloxane.While introducing the elastomeric properties of PDMS into the composites,a layer of CNTs conductive interface layer was constructed between PDMS and the fiber.The conductive interface layer enables the material to be tested for resistance changes even when subjected to tensile deformation exceed the percentage of breaking elongation of the fiber(<20%),making the material highly promising in the field of multi-function strain sensors.At the same time,the method of constructing the conductive path inside the materials by using the template provides an idea for monitoring the internal aging and damage of the materials.