| Due to its high axial strength,toughness,elastic modulus,tensile strength and good electrical properties,multi-walled carbon nanotubes(MWCNTs)have become the research hotspot in the field of polymer materials science.As a kind of high aspect ratio one-dimensional material,carbon nanotubes are widely used as filler in polymer modification,which can give polymer materials excellent mechanical properties,thermal stability,electrical conductivity and thermal conductivity.In recent years,due to its high cost performance,carbon nanotubes are widely used in the preparation of conductive polymer composites.As we all know,the key to the preparation of conductive polymer composites is whether to reduce the percolation value(critical filler content,when the content exceeds this value,the formation of infiltration network).However,other conventional filler dispersions often require higher loadings to form a conductive network due to spatial effects.Therefore,a good distribution of carbon nanotubes will determine the ultimate conductivity and other properties of the composite.This article focuses on exploring the appropriate amount of filler to adjust the effective distribution of carbon nanotubes in the polymer matrix,the preparation of high performance polymer functional materials.In order to solve the above problems of filler dispersion,this paper synthesizes a new type of composite modifier on the basis of reading a large amount of literature,and the test proves that the modifier can help the filler to disperse better in the group.Based on this,the relationship between the content of carbon nanotubes and the thermodynamics,rheology and conductivity of carbon nanofiller/polymer composites was explored.Three kinds of polymer composites with different morphologies were designed,the percolation value of the material was reduced,and the conductivity of the material was improved.The main contents include the following aspects:(1)Carbon nanotube packing was wrapped by the synthesis of(PSS and CTAB),and then the A new type of conductive material was prepared by controlled in situ polymerization of biomass castor oil,4,4'-diphenylmethane diisocyanate(MDI)and 1,4-butanediol(BDO)And thermal resistance,as well as significantly improved mechanical properties of polyurethane matrix composites.Studies have shown that the introduction of carbon nanotubes as a filler can significantly improve the thermal stability of polyurethane and related thermal properties.And the threshold of permeability drops obviously,and the conductivity is also greatly improved.This provides a good idea for the preparation of materials with adjustable conductivity.(2)A novel modifier(PSS-CTAB)prepared by incorporating a combination of amphiphilic surfactants(sodium poly(sodium 4-styrenesulfonate)and cetyltrimethylammonium bromide)Multi-walled carbon nanotubes(MWCNTs)are modified with non-covalently bonded structures,which improves the dispersion of multi-walled carbon nanotubes in a solvent.Then,new functionalized MWCNTs were introduced into PCL matrix and PCL/MWCTNTs complexes were prepared by solution solidification.The conductivity,mechanical properties and thermal stability of PCL/MWCTNT composites were evaluated in detail.The corresponding relationship between the properties of PCL composites and CNT-induced crystallization behavior was also analyzed.Finally,from the perspective of structural dete rminacy,the mechanism of phase behavior on the formation of conductive networks is revealed in depth.(3)Polylactic acid is a more difficult to crystallize semi-crystalline polymer.In this paper,the introduction of carbon nanotubes,graphite and graphe ne as nucleating agent significantly increased the crystallization rate and crystallinity of polylactic acid,while the different induced The relationship between the nucleating agent and the crystallinity and morphology of polylactic acid composites was d iscussed in detail from the view of structure-property.It provides a new idea for preparing high-performance polylactic acid / carbon nanocomposites. |
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