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

In this paper, a novel technique for preparation of polymer nanocomposites, reverse micelle template-in situ polymerization nano-compounding has been developed, by which the PMMA/Eu(OH)₃/EG, PMMA/Ni(OH)₂/EG, PMMA/Ce(OH)₃-Pr₂O₃/NanoG and PANI/Ce(OH)₃-Pr₂O₃/NanoG ternary nanocomposites were successfully prepared. The process and mechanisms of slipping, exfoliation to layered graphite or NanoG and compounding with PMMA or PANI and inorganic nanoparticle on nano-scale were systemically studied. The electrical conductivities and thermal stability of the nanocomposites were also investigated. Based on the experimental results, a modified electrical conductive model as well as thermal stability model for polymer-based composites was proposed. In addition, the electrical and thermal stability polymer/inorganic-nanoparticles/graphite nanocomposites prepared by reverse micelle template-in situ polymerization nano-compounding technology. This research develops the compounding technique for nanocomposites, as well as the reverse micelle template-in situ polymerization, the electrical conductive theories of polymer based composites. The main outcomes are listed as follows:1. A reverse micelle template-in situ polymerization nano-compounding technology has established, by which the graphite with weakly combined structure are exfoliated and then 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 /NanoG and PANI/Ce(OH)₃-Pr₂O₃/NanoG ternary nanocomposites were obtained. Their structures and properties were characterized by SEM, TEM, XRD, the electrical conductivity, FT-IR and heat-decomposition temperature etc.The reverse micelle system is of advantage to the polymer monomer and inorganic particle diffusion to the exfoliated graphite layers and form composites on nanoscale. One the one hand, the surfactant was employed to form reverse micelle template for preparing inorganic nanoparticles with well distribution, as well as was used for the surface modify reagent of graphite and inorganic nanoparticles, so as to improve the consistency and appetency between polymer, graphite and inorganic nanoparticles. On the other hand, reverse micelles are water-in-oil microemlsions. The "water pool" in reverse micelle is formed by surfactant spontaneously arraying in non-aqueous solvent. This provides an excellent micro-reactor for the preparation of nanoparticles. It has many advantages, such as the particles size is well distributed, and its diameter can be well controlled, etc. Because of this virtue, the inorganic particles can be dispersed uniformly in the polymer on nanoscale, so as to resolve the problem of nanoparticles aggregates. Moreover, the weak interaction between layers of graphite lays the foundation for its exfoliation and nano-compounding with polymer and inorganic nanoparticles.The results show that the interlayer exfoliation of graphite and nano-compounding with PMMA and inorganic nanoparticles proceeded stepwise. In addition, the intercalated or exfoliated nanocomposites can be also prepared respectively by controlling the conditions of preparation.2. Studyied on the structure and property of polymer/inorganic-nanoparticles/ graphite ternary nanocompositesIt was studied in virtue of modern times analysis test technique that the structure of polymer/inorganic-nanoparticles/graphite ternary nanocomposites, graphite dispersing in different polymer matrix and the change of nanocomposites thermal stability with compounding graphite, inorganic nanoparticles and so on.The graphite has a high aspect ratio (width-to-thickness), size and volume in the polymer/inorganic-nanoparticles/graphite ternary nanocomposites via reverse micelle template-in situ polymerization nano-compounding technology. The inorganic nanoparticles in the nanocomposites have a self-assembly phenomenon to form the clubbed or dendrites structure. This microstructure is of advantage to improve the interface appetency of graphite and polymer so as to enhance the thermal stability of the nanocomposite.3. It was studied that the electrical conductivity and its mechanism of PANI/Ce(OH)₃-Pr₂O₃/NanoG ternary nanocomposites in order to seek an effective method to prepare polymer/graphite electricalconductive composites of low loading level and high electrical conductivity.The nano-structures in the PANI/Pr₂O₃-Ce(OH)₃/NanoG ternary nanocomposites can be obtained via reverse micelle template-in situ polymerization nano-compounding. Circuit-network is formed through the touching of graphite sheets with large aspect ratio. In addition, the electroconductive polyhedrons with site-bond-surface coordinated pattern are formed by intercalating PANI and inorganic nanoparticles into graphite, then extend the effective diameter of conducting particles, thus electroconductive charges are no more confined within a single particle, but jump among conducting polyhedrons to produce tunnel current, accordingly, the conducting percolation threshold of PANI/Pr₂O₃-Ce(OH)₃/NanoG ternary nanocomposites in room temperature is very low, less than 1.0 wt%.4. A polymer precursor nano-compounding technology has developed, by which Ce_0.8Pr_0.2O₂/NanoG nanocomposite was prepared and its preparation conditions and structure characteristic were characterized.A new effective method has established for rare earths oxide/NanoG nanocomposite and that resolves the problem of nanoparticles aggregates. The results show that the heat treatment temperature is 800-1100°C. The Pr atoms entered completely into the CeO₂ crystal lattice and formed a cubic solid solutions Ce_0.8Pr_0.2O₂ nanoparticles and the average crystallite size is in the range of 15-20 nm. This technical can be used widely to prepare other inorganic nanocomposite.