Reseach On Modification Of Nano CaCO₃ And The Bubble Morphology Of PP/AC/CaCO₃ Composite Foaming Plastics

This paper conducted a longitudinal study of the surface modification of nano calcium carbonate (nano-CaCO3) and the bubble morphology of modified nano-CaCO3/ Azodicarbonamide (AC vesicant)/polypropylene (PP) composite extruding foaming system.In the part of the surface modification of nano-CaCO3, elaborated on this theories of the the calcium carbonate nanoparticles modification mechanism and molecular structure model and the characteristics of particles, chose dry heat activation process, and used stearic acid, titanate coupling agent, polypropylene wax (PPW) of the ternary compound modifier to modify the nano-calcium carbonate;took on the evaluation of the results by two indicators of activation Degree and oil absorption, proposed optimal level of portfolio of the compound modifier, also took on in-depth discussion of the used surface modifier on the adsorption of calcium carbonate molecular mechanism, provided guidance for the industrial production of modified nano-CaCO3.In the part of the study of the bubble morphology of modified nano-CaCO3/AC/PP composite extruding foaming system, elaborated on the mechanism of microcellular foaming and the factors of the cell morphology in the foaming extrusion process. Used single factor rotation method, analyzed the the four indicators of the average diameter of longitudinal section of vesicles, the cell area ratio, variable degree of bubble shape, bubble inclination angle by the change of the nose temperature, screw speed, AC vesicant's content and the content of modified and unmodified nano calcium carbonate;the bubble shape of the composite systems which were added respectively modified and unmodified nano-calcium carbonate were compared to study and summarize the differences between the two composite foaming systems in bubble shape, and provided some references for production and related research.Finally, took on the research of the cell morphology of the composite extrusion foaming system in the orthogonal test and acquired the order of the factors and the optimal level of portfolio of the factors by the range analysis method. Analysed the experimental data by using advanced statistical software, acquired the regression model of average diameter and the cell area ratio of longitudinal section of vesicles, the results of residual analysis showed that the model could be used for experimental guidance and forecasts;under the condition of existing equipment, the optimal range of processing parameters were acquired by using regression models, and experimental verification showed that the results could be a good guidance for the experiments and the actual production.