| As a new additive manufacturing technology,polymer melt electrospinning technology is widely used in micro-nano manufacturing fields due to its good controllability,low preparation cost and wide material selectivity,such as biological tissue engineering,flexible electronics and software robots.The ordered fiber prepared by the melt electrospinning technology has high porosity and large specific surface area,and has great technical advantages compared with the conventional preparation method.This paper first analyzes the research progress of electrospinning direct writing technology at home and abroad,and then studies the requirements of biological tissue engineering,from the aspects of ordered fiber adhesion,fineness controllability and continuous gradual change:(1)Aiming at the problem of adhesion of tissue engineering scaffolds,the effects of nozzle temperature,inter-fiber lap time interval and ambient temperature on the degree of fiber bonding during the preparation process were investigated.The thermogravimetric analyzer(TGA)was used for characterization.analysis.The research shows that with the increase of the temperature of the nozzle,the adhesion between the fibers increases first,and then decreases after a slight fluctuation,and the bonding effect is best in the interval of 190℃-210℃;The extension of the thermal fiber lap time interval,the bonding effect between the fibers is continuously decreased;the increase of the ambient temperature enhances the bonding time of the fiber and has a great influence on the bonding effect.(2)In view of the controllability of the fineness of tissue engineering scaffold fibers,the pneumatic feed system was used to improve the control precision,and the controllability of the ordered fibers in the preparation process was investigated.The distance from the nozzle to the receiving plate,the inlet pressure and the nozzle diameter were taken as parameters.Variables,through the single factor experiment to explore the corresponding relationship and trend of fiber diameter corresponding to different single variables.The three variables were arranged in a combination of 8950 experiments to obtain three different sets of two-factor variables corresponding to the fiber diameter data,and the relationship between the fiber diameters under different process combinations was obtained.Using six sets of mathematical models,three different sets of data are fitted to obtain the relevant fitting surface and fitting formula,and the fitting parameters of different models are compared to obtain the surface equation which best matches the experimental results.The results of the obtained equations are verified by the unmeasured points outside the interval.It is proved that the experimental data has a high degree of coincidence with the theoretical calculation results.The formula has a good prediction and guidance for the actual experimental results.(3)Aiming at the problem of continuous gradual change in the preparation process of the stent,the effects of the inlet pressure and the moving speed of the platform on the diameter change of the obtained fiber were studied.According to the existing empirical function,the fitting verification is carried out to obtain the parameters such as the fitting degree and the residual.The results show that the empirical function accords with the actual result and fits the curve formula according to the experimental data.In the experiment,the inlet pressure and the platform moving speed were changed respectively,and the three-dimensional scaffold with gradient of fiber diameter gradient was prepared,and the morphology of the scaffold was analyzed.In summary,the electrospinning direct writing molding equipment is used to explore the three problems of adhesiveness,fineness controllability and continuous gradual change in the application field,which provides data accumulation for the subsequent industrialization of electrospinning.It also provides a technical basis for subsequent development of other applications. |
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