Preparation And Application Of Polymer Microfiber Used For Water Conveyance

Polymer fibers have excellent material properties and surface structure, such as high specific surface area, high porosity,low density, good ductility, surface effect,small size effect and many other special physical and chemical properties,now a growing number of polymer microfibers is being researched and produced,which has a good application prospect.The physical and chemical performance of Polypropylene (PP) that has a low price,a lot of raw materials and fiber products is quite stable,and it is widely accepted in industry.The preparation methods and application areas of PP fibers are worth the further research and development.Polypropylene and its composite materials are taken as spinning raw materials in this thesis.Melt differential electrospinning method is used to produce hydrophilic modified microfibers,and to explore the effects of different hydrophilic modified ways (outer coating method and adding method) and fiber surface structures (diameter, orientation and pore) on hydrophilic performances (water absorption,wicking,water conveyance) of polypropylene microfibers.At the same time,the structure of original melt differential electrospinning single nozzle is improved,and electric controlling test bench of one in four spinning nozzle is built.Also,the influence of convex hemisphere structure inside the nozzle on electric field intensity is analyzed through Ansys simulation on three dimensional electric field.Experiment and simulation results show that the method of adding enhances the effect of fiber hydrophilic obviously,and provides a good durability.Outer coating method makes fibers have a better wettability,but the poorer durability. Using two kinds of additives together,the hydrophilic performances(water absorption rate/water conveyance rate and wicking height) have no superposition effect;The process of water molecules along the fiber horizontal and vertical transportation,on the whole,is mutual constrainted, which has relationship to the degree of fiber diameter, density, pattern, surface structure and group composition.The more pores and surface roughness fibers have,the better hydrophilicity fibers can have.Reducing fiber diameter and increasing the degree of orientation, can obviously increase the wicking height value;Convex hemisphere structure on inner wall of differential nozzle has a certain strengthening and concentration effect on increasing the electric field intensity around nozzle.The increase of nozzle diameter mainly causes the increase of field intensity peak value,while the increase of the number of columns mainly causes the increase of the continuous distance of field intensity peak.Moreover,the external electric field has got no interference from convex hemisphere/which shows that the structure of the hemisphere is helpful to efficient, durable and stable spinning process.