Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Special structural materials

The Study on Controllable Preparation and Performance of Polyurethane Nano-fiber/net

Author HuJuanPing
Tutor DingBin
School Donghua University
Course Materials Processing Engineering
Keywords Electrospinning Electrostatic spray Network Nano cobweb Polyurethane Mechanical Breathable moisture permeability
CLC TB383.1
Type Master's thesis
Year 2012
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Electrospinning technique is a direct, continuous preparation methods of the polymer nanofibers. It is very different from the conventional method, which is mainly by means of a high voltage electrostatic field so that the polymer solution or melt charged and deformed, drape tapered droplets formed at the nozzle end; over its surface tension when the surface of the droplets charge repulsion when, in the droplet surfaces will be high-speed jet of the polymer fine liquid stream; tiny liquid flow within a short distance through the electric force of the high-speed stretch, solvent evaporation and curing, and ultimately the reception plate is formed of polymer fibers . Electro-spun fibers prepared with a high specific surface area, high porosity, which makes electro-spun fibers have a wide range of potential applications in the field of information, energy, environmental, biomedical, and national security. Fiber diameter distribution obtained by the electrostatic spinning technique are generally between 100-500nm, and only when the fiber diameter is reduced to 50nm or less, the material generated nanometer effect before the most significant. Electrospinning technology but difficult to achieve large scale preparation of nanofibers of 50 nm or less, which largely limits the application of the nanofibers. In recent years, with the rapid development of electrospinning students accompanied by electrospinning the electrostatic spray Network technology being the great concern of researchers. Can step ordinary electrostatic spinning fiber holder a 2D mesh fiber membrane material was prepared using the electrostatic spray network technology, such two-dimensional network structure of the fiber diameter size is only within the range of 5-40 nm, and thus shows a number of excellent properties, such as large specific surface area, high porosity, etc.. Polyurethane (PU) in a polymer main chain is a polymer containing many carbamate group, and it has an excellent toughness and flexibility, good abrasion resistance, flex resistance, solvent resistance, and easy molding and controlled performance advantages and an irreplaceable applications in many areas. In addition, the use of polyurethane prepared from the resulting fiber membrane with excellent breathable performance, so that it has a broad application prospects in the military, high-end clothing and biomedical. This topic first describes the basic theory of electrospinning technology, as well as in the process of electrospinning nanofibers impact of various important parameters. This topic use the electrostatic spray Network technology step prepared PU nano spider web, by means of the FE-SEM as the main analytical tools, the first solution system on the formation and structure of PU nano cobweb morphology. PU fibronectin was found that, after a certain amount of salt is added to the solution of 7 wt% of the PU can be obtained PU nano cobweb, PU solution was added 3 wt% of deionized water, the increased nano spider coverage area reduced , fiber diameter decreases. In addition, different types of PU solution will also impact on the structure and morphology of the nano cobweb. Experiments found that the electrostatic spray network using the density of the PU, the phenomenon of adhesion of the fibers is evident, small nano spider coverage area, the fiber diameter is small. On this basis, the topic also discussed the voltage, receiver distance, humidity, different additives on the structure and morphology of the PU nano cobweb. This study is a PU nano cobweb stretching, wear-resistant, breathable performance. The experimental results show that the the PU fibers and nano-structure and morphology of the spider web and covers an area the size of the tensile, wear-resistant, breathable performance has played a decisive role.

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