聚氨酯纳米纤维结构体的制备及其性能分析.

Compared with two-dimensional electrospinning nanofiber membranes, three-dimensional (3D) electrospinning nanofiber structures, which are preferred by people, are fluffier, and have more internal pores with good connectivity. However, most of the 3D structures built by traditional methods such as stitching and layer by layer stacking have resulted in the waste of raw materials and the layer separation phenomenon, which greatly limits the use of products. In this paper, polyurethane nanofiber structures with stable three-dimensional structure were prepared from polyurethane (PU) and polyvinyl butyral (PVB) by electrospinning technology and freeze-drying technology. Through various instruments and self-assembly experiments, the morphology and structure of 3D polyurethane nanofiber structures were analyzed, and the thermal insulation, oil absorption and mechanical properties of polyurethane nanofiber structures were studied. Firstly, two-dimensional nanofiber membranes were prepared by using rotating drum as the collector during electrospinning. According to the research, when the mass ratio of Pu to PVB was 8:2, the viscosity and conductivity of the polymer solution were moderate, and the morphology of the nanofibers were desirable. There were great differences in the microstructure of two-dimensional fiber collection and three-dimensional fiber collection. SEM images showed that when the solution concentration was 14% and the mass ratio of Pu to PVB was 8:2, the fibers in two-dimensional nanofiber membranes were smooth, while the fibers in three-dimensional nanofiber structure were curled and intertwined. The infrared spectrum showed that there were characteristic absorption peaks of PU and PVB in three-dimensional polyurethane nanofiber structures at the same time. PVB could precipitate and adhere to the nanofiber structures during the process of washing and freeze-drying. Finally, the performance of 3D polyurethane nanofiber structures was tested and analyzed. Thermal conductivity test showed that the thermal coefficients of 3D nanofiber structures with PU/PVB concentrations of 12%, 14%, 16% and 18% were 0.0580, 0.0506, 0.0584 and 0.0574 W/(m · K), respectively, all lower than those of 2D nanofiber membranes. Oil absorption test showed that the adsorption rates of 3D nanofiber structure for n-hexane, vacuum pump oil, engine oil and sunflower seed oil were 3.88, 5.68, 5.2 g/g and 5.64 g/g, respectively. The adsorption rate for organic phase oil was higher than that of oil phase oil, and 3D nanofiber structures also presented notable recycling performance. Mechanical test showed that it could rebound rapidly after bearing a certain pressure for a long time. The result showed that 3D polyurethane nanofiber structure had a stable three-dimensional spatial structure which was not easy to collapse, and could be applied to a variety of fields. [ABSTRACT FROM AUTHOR]