Preparation, Properties And Related Mechanics Issues Of Polymeric Nanocomposites

Polymeric nanocomposite is an important new material. It has many excellent properties which being differ from macroscopical composite materials, and gives new direction and approach to research and prepare new materials. Therefor, it gets much regard in the world. The characteristic scale of the polymeric nanocomposite's reinforcement is a few decades nanometer levels, which less than the cable length of the long-chain macromolecule. The inner structures(the cell strutures of the macromolecule, chain structures, aggregative state structures etc.) of the polymeric nanocomposite have multiscale build characteristics of spanning matter layers. Adopting classical micromechanics, continuity mechanics and rheology theory models to describe them had been localization. In this paper, basing on the preparation of the polymeric nanocomposite, we tried to study their mechanics properties by using multiscale homogenization theory.In this paper, the preparation, properties and related mechanics issues of polymeric nanocomposites have been studied. Main research contents and creative results as follows:1. Basing on the preparation of (NH2)4PcCu and SiO2 nanograins, the PA6/SiO2 nanocomposites and the PA6/(NH2)4PcCu nanocomposites were prepared by in-situ polymerization. Their microcosmic structure characteristics were described and their mechanics and functional properties were studied. The results indicated that when the content of the SiO2 nanograins is 5%, the tensile strength and elastic module of the PA6/SiO2 nanocomposites increase 41% and 47% than pure PA6; when the content of the SiO2 nanograins is 3%, the impact strength and microhardness of the nanocomposites increase 59% and 32% than pure PA6. When the content of the (NH2)4PcCu nanograins is 0.8%, the tensile strength, elastic module and impact strength of the PA6/(NH2)4PcCu nanocomposites increase 12%, 24% and 139% than pure PA6. The ultraviolet filtration, anti-ultraviolet aging and the infrared thermal storage retardation of the PA6/(NH2)4PcCu nanocomposites had obviously improved with the addition of the (NH2)4PcCu nanograins.2. Basing on the microcosmic structure characteristics and mechanics properties of the nanocompsities, the multiscale analysis model was built. The influences of the model's parameters including the polymer crystallinity, the elastic module of the polymer crystal, the elastic modulus of the nanograin and the nanograin's fraction on the equivalent elastic modulus of the polymeric nanocomposite were discussed by the multiscale homogenization method. We had compared the experiment results with the theory results, the results indicated that the experiment results basically tallied with the theory results, on the premise of the theory coming into existence, i.e., in case of nanograin dispersing evenly. Therefor, the validity of the model was validated.3. Porous materials are a sort of lightweight structural materials. The accession of the nanograins in its matrix material could endow it with definite functionality, and brought the multiscale questions in its structure. For better understanding the influence of the nanograins on the porous polymeric nanocomposites, the PMMA porous material, the porous PMMA/SiO2 nanocomposites and the porous PMMA/TiO2 nanocomposites were prepared by MMA itself polymerization foaming method. We studied the functionality of the TiO2 nanograins initially. Their mechanics properties were studied and the experiment results were analyzed. The results indicated that the compressive stress-strain curves of the nanocomposites had obvious three phases characters of the porous foams, i.e., linear elastic phase, plastic yield flat phase and compact phase. Along with the nanograins content of the nanocomposites increasing, the compressive elastic modulus of the nanocomposites augmented. The nanocomposites that which had the same nanograins content, with the transfiguration speed increasing, their compressive strength added.4. The theory model of the porous polymeric nanocomposite was built by the multiscale successive homogenization theory. The relations between the macroscopical equivalent elastic constant of the nanocomposites and the material constant of the polymeric matrix materials and the nanograins and the nanograins content were studied. We had compared the experiment results with the theory results, the results indicated that the former was a little less than the latter in magnitude, but both of their increase trends were accordantly. Thus it shown that the experiment results were accorded with the theory results, the validity of the model was validated.