| With the development of the times and the continuous improvement of the level of science and technology,people use melt extrusion method,two-way stretching method,phase separation method,flash method and electrostatic spinning method and other processes,in order to prepare functional materials with excellent waterproof permeability and moisture permeability.Electrospinning refers to the polymer spinning solution is sprayed and stretched by high voltage electrostatic field force,and then the micro-nano fibers are obtained.Electrospinning can prepare fibers with a diameter of hundreds of nanometers.The materials made are large in surface area,small in pore size and high in porosity.At present,there are many researches on the preparation of waterproof and permeable materials by electrospinning,but most of the researches use pinhead spinning scheme in the laboratory.In order to explore the mass preparation scheme of micro-nano waterproof and permeable materials,the needle-free electrospinning method was adopted in this paper,and the research was carried out respectively from two spinning materials,polyester polyurethane and polyether sulfone.The gradient structure of materials was controlled by fiber diameter and pore size,so as to achieve the gradient of hydrophilic and hydrophobic functions of materials,and the batch preparation technology scheme of waterproof and permeable materials by electrospinning was explored.The main research contents of this topic are as follows:（1）The optimal experimental parameters of electrostatic spinning for polyester TPU were determined by orthogonal test:the mass fraction of spinning solution was 15 wt%,the spinning voltage was 50 KV and the receiving distance was 12 cm.Triton X-100 additive was introduced to reduce the viscosity of the spinning solution,so as to alleviate the phenomena of fiber shrinkage and edging in the process of electrostatic spinning of polyester TPU.According to the performance test analysis,the introduction of Triton X-100 does not damage the molecular structure of polyester TPU.Although the moisture permeability of the material is slightly lower than that of the material without Triton X-100 additive,it can improve the contact Angle,hydrostatic pressure and breaking strength of the material.The average pore size of the prepared polyester TPU/Triton X-100 assistant micro-nano fiber material is 0.09～1.7μm,the contact angle is 111.35～121.55°,the hydrostatic pressure is 6.49～7.12 KPa,and the permeability is4654～5580 g·m-2·d-1.The breaking strength is 20.2～21.6 N.（2）The solution preparation scheme of PES electrospinning continuous production was investigated:PES mass fraction was 20 wt%,and the solvent was N-methylpyrrolidone（NMP）.And on that basis,the properties of four kinds of samples with liquid feeding speed of 0.3 m/min,0.9 m/min,1.5 m/min and 2.1 m/min were characterized.It is found that the average fiber diameter of PES micro-nano waterproof and permeable materials with different liquid feeding speed is 242～345 nm and the average pore diameter is 9.1091～9.5115μm,contact angle is over140°,hydrostatic pressure is 5.86～7.15 KPa,moisture permeability is 5749～7033 g·m-2·d-1,air permeability is 59.73～219.95 mm·s-1,breaking strength is 20.6～31 N.The prepared PES micro-nano materials,play a good hydrophobicity and moisture permeability advantages,the permeability of the prepared material can be adjusted by the liquid speed,for the industrialization of the preparation to provide a convenient quality control means.（3）PES-TPU-PP three-layer composite micro-nano fiber material with hydrophobic gradient effect was designed and prepared.After testing,and it is found that the design of PES-TPU-PP three-layer composite micro-nano fiber materials of hydrophobicity,moisture permeability,fracture strength has been greatly improved than TPU-PP,showing more excellent waterproof and moisture permeability properties and mechanical properties.More conducive to the application of real life.（4）In order to explore the practical application scenarios of electrostatic spinning micro-nano waterproof and permeable materials,materials with better water and air permeability were selected as the bottom layer of diapers,and compared with commercial diapers.It is found that PES-PP and PES-TPU-PP micro-nano waterproof and permeable materials prepared by needle-free electrospinning technology not only meet the basic leak-proof performance requirements of diapers,but also have excellent breathability and can be used as the leak-proof underlying material of diapers.According to the needle-free electrospinning series experiments and analysis tests,the prepared polyester TPU/Triton X-100 auxiliary micro-nano fiber material,strong hydrophobic PES micro-nano fiber material,PES-TPU-PP three-layer composite micro-nano fiber material has excellent waterproof and moisture permeability performance.In practical application,different spinning formula and different process parameters can be selected according to the actual performance requirements.The research results of this subject provide the solution idea and key technical scheme for the batch preparation of electrostatic spinning waterproof and permeable materials. |
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