Studies On Reverse Micelle Template-In Situ Polymerization Nano-Compounding Technology & Ternary Nanocomposites

Because of its special properties, polymer nanocomposites has been deeplyinvestigated in recent years, but many research works need to be done to the applicationof polymer nanocomposites. In this dissertation, a novel technique for preparation ofpolymer nanocomposites, reverse micelle template-in situ polymerizationnano-compounding has been developed. By using the proposed technique thePMMA/Eu(OH)₃/EG, PMMA/Ni(OH)₂/EG, PMMA/Ce(OH)₃-Pr₂O₃/NanoG,PANI/Ce(OH)₃-Pr₂O₃/NanoG , PPy/AgCl/NanoG ternary nanocomposites weresuccessfully prepared. The process and mechanisms of slipping, exfoliation to layeredgraphite or NanoG and compounding with PMMA or PANI and inorganic nanoparticleon nano-scale were systemically studied. The electrical conductivities and thermalstability of the nanocomposites were also investigated. Based on the experimentalresults, a modified electrical conductive model as well as thermal stability model forpolymer-based composites was proposed. In addition, the electrical and thermal stabilitypolymer/inorganic-nanoparticles/ graphite nanocomposites were prepared by reversemicelle template-in situ polymerization nano-compounding technology. This researchlaid foundations for develops the compounding technique for nanocomposites, as wellas the reverse micelle template-in situ polymerization, the electrical conductive theoriesof polymer based composites. And PPy/AgCl/NanoG was studied by dynamics andmesodyn method. The main outcomes are listed as follows:A reverse micelle template-in situ polymerization nano-compounding technologyhas established. Thus, the graphite with weakly combined structure are exfoliated andthen compounded with PMMA or PANI and inorganic nanoparticle at nanoscale.The PMMA/Eu(OH)₃/EG; PMMA/Ni(OH)₂/EG, PMMA/Ce(OH)₃-Pr₂O₃/NanoGand PANI/Ce(OH)₃-Pr₂O₃/NanoG ternary nanocomposites were obtained. Theirstructures and properties were characterized by SEM, TEM, XRD, the electricalconductivity, FT-IR and heat-decomposition temperature etc.The reverse micelle system is conducive to the polymer monomer and inorganicparticle diffusion to the exfoliated graphite layers and formation of composites on nanoscale. One the one hand, the surfactant was employed to form reverse micelletemplate for preparing inorganic nanoparticles with well distribution, as well as wasused for the surface modify reagent of graphite and inorganic nanoparticles to improvethe consistency and appetency between polymer, graphite and inorganic nanoparticles.On the other hand, reverse micelles are water-in-oil microemlsions. The "water pool" inreverse micelle is formed by surfactant spontaneously arraying in non-aqueous solvent.It provides an excellent micro-reactor for the preparation of nanoparticles. It has manyadvantages, such as the particles size is well distributed, and its diameter can be wellcontrolled, etc. Because of this virtue, the inorganic particles can be dispersed uniformlyin the polymer on nanoscale, so as to resolve the problem of nanoparticles aggregates.Moreover, the weak interaction between layers of graphite laid the foundation for itsexfoliation and nano-compounding with polymer and inorganic nanoparticles.The results show that the interlayer exfoliation of graphite and nano-compoundingwith PMMA and inorganic nanoparticles proceeded stepwise. In addition, theintercalated or exfoliated nanocomposites can also be prepared by controlling theconditions of preparation.It was studied in virtue of advanced test experimental technique that the structureof polymer/inorganic-nanoparticles/graphite temary nanocomposites, graphitedispersing in different polymer matrix and the change of nanocomposites thermalstability with compounding graphite, inorganic nanoparticles and so on.The graphite has a high aspect ratio (width-to-thickness), size and volume in thepolymer/inorganic-nanoparticles/graphite temary nanocomposites via reverse micelletemplate-in situ polymerization nano-compounding technology. The inorganicnanoparticles in the nanocomposites have a self-assembly phenomenon to form theclubbed or dendrites structure. This microstructure has advantage to improve theinterface appetency of graphite and polymer so as to enhance the thermal stability of thenanocomposite.It was studied that the electrical conductivity and its mechanism ofPANI/Ce(OH)₃-Pr₂O₃/NanoG temary nanocomposites in order to seek an effectivemethod to prepare polymer/graphite electricalconductive composites of low loadinglevel and high electrical conductivity.The nano-structures in the PANI/Pr₂O₃-Ce(OH)₃/NanoG temary nanocompositescan be obtained via reverse micelle template-in situ polymerization nano-compounding.Circuit-network is formed through the touchingof graphite sheets with large aspect ratio. In addition, the electroconductive polyhedrons with site-bond-surface coordinatedpattern are formed by intercalating PANI and inorganic nanoparticles into graphite, thenextend the effective diameter of conducting particles, thus electroconductive charges areno more confined within a single particle, but jump among conducting polyhedrons toproduce tunnel current, accordingly, the conducting percolation threshold ofPANI/Pr₂O₃-Ce(OH)₃/NanoG temary nanocomposites in room temperature is very low,less than 1.0 wt%.Using the technique of microemulsion polymerization, the NanoG/AgCl/ PPynanocomposite was prepared by polymerization of pyrrole in site through reversemicroemulsion as template.The PPy/AgCl/NanoG nanocomposite was prepared by polymerization of pyrrolein site through reverse microemulsion as template. And the nanocomposite was wasstudied by dynamics and mesodyn method. The results indicate that nano-AgCl andgraphite nanosheets were dispersed in the PPy matrix. The strong interaction betweenthis two different nano-substance and PPy is discovered. According to thefour-point-probe test, the electrical conductivity of NanoG/AgCl/PPy nanocompositewas higher than the electrical conductivity of pure PPy thanks to the introduction ofNanoG. On the nano-scale, a majority of sudstances was welt-dispersed, and have vastinterface, which lead to a high potential energy. However, there was a littleconglomeration, and AgCl conglomerated easily. Phase separation did not happen innanocomposite.