Measurement And Control Of PVT Characteristics Of Supercritical Fluid Micro-expansion Polypropylene Injection Products

Micro-foamed polymer injection molded products are hotspots in various fields due to their advantages of light weight,high strength and energy saving.Micro-foamed polypropylene is widely used in vehicles,drones and medical fields,but its products have the problem of surface silver streaks and brittle materials,resulting in increased rework costs.In this paper,polypropylene is used as the matrix.For the first time,the test principle of free cooling and pressure reduction in full molding cycle is adopted to find a solution to the problem of application of micro-foamed polymer materials.Finally,the performance and regulation of micro-foamed polymer parts are improved.help.main tasks as follows:1.Develop a novel test method and experimental device for homogeneous fluid testing of supercritical fluid polymer,and study a supercritical micro-foamed polypropylene material to analyze its PVT characteristics and conventional polypropylene polymer PVT.The difference in characteristics.Analyze the basic principle of polymer PVT test and summarize the key factors of influence.On this basis,this paper designs and develops a device that can test the PVT characteristics of micro-foamed polymer on the injection molding machine platform.The temperature and pressure of the test are all from In the process of polymer injection molding,the obtained PVT characteristics are closer to the actual processing and molding process,so it has the function of guiding mold development,establishing CAE database,optimizing processing and simulation analysis.The P-V-T characteristics of a micro-foamed semi-crystalline polymer polypropylene(PP)material were tested.The results of PVT three-dimensional characteristic data of micro-expanded polypropylene under various molding conditions were obtained.The test broke through the limitations of traditional test methods.The global data processing method was used to simulate the regression analysis of test data in PVT three-dimensional space.PVT The characteristic results reflect the test process and actual molding more accurately and accurately.The modified dual-domain Tait equation of state is used to compare the correlation data of the experimental data.The equation fits the experimental results well,which proves the credibility of the equation and the feasibility of the self-testing technical means.Parameter value.2.The effect of foaming parameters on PVT characteristics during supercritical fluid micro-expansion polypropylene molding was studied.The PVT characteristics of the microfoamed semi-crystalline polymer polypropylene(PP)material were tested.The PVT three-dimensional characteristic data of micro-expanded polypropylene under various gas injection pressures were obtained,and the effect of gas injection pressure on the PVT characteristics of micro-foamed polypropylene was studied.Experiments show that different gas injection pressures have a direct impact on the micro-foamed homogeneous melt,and the surface quality of the product can be improved by precisely controlling the gas injection volume.3.The effect of PVT characteristics of supercritical fluid micro-expanded polypropylene on microscopic cell,surface quality and mechanical properties of the product was studied.By controlling the temperature and pressure in the cavity,the cell structure of supercritical fluid microfoam injection molding polypropylene was controlled.The cell structure of microporous PP injection products under different molding temperature and pressure conditions was studied.Changes in mechanical properties and surface quality.