| Melt electrospinning process without the use of organic solvent,is an efficient,environmental protection fiber manufacturing technology,has great potential in the field of fiber material industrial manufacturing.At present,the melt electrostatic spinning technology mainly uses polypropylene(PP)with lower melting point as the raw material,and uses less polyethylene terephthalate(PET)with better mechanical properties.The reason is that the viscosity of PET melt is larger,resulting in the diameter of the spun fiber is thicker,which limits the application range of this material.However,the surface structure,pore structure and mechanical properties of small-diameter PET melt electrostatic spinning fiber materials prepared by advanced refining technology can be significantly improved,which has great application prospects in filtration separation,cold insulation,energy catalysis and other fields.Therefore,in order to prepare small-diameter melt electrostatic spinning PET fiber material,this study takes PET as raw material,and by changing the process parameters of melt electrostatic spinning technology(spinning temperature,spinneret aperture,spinning voltage,receiving distance,receiving area,etc.),the change rule of PET fiber diameter is explored,and the diameter of PET fiber is initially reduced.Then,the viscosity of PET melt was effectively reduced by the introduction of polyethylene glycol(PEG)viscosity reducer in PET,and the influence of PEG content on fiber diameter and mechanical properties was investigated.The further refinement of PET fiber was realized,and the melt electrostatic spinning PET microfiber material with excellent mechanical properties was prepared.On this basis,the topic further carried out hot pressing treatment on PET,and explored the fiber apparent morphology,mechanical properties,pore structure and macro structure change rule of PET microfiber materials under different hot pressing parameters,and explored its potential application value in the field of filtration.Specific research conclusions are as follows:(1)By optimizing the process parameters in the process of melt electrostatic spinning,it is determined that the spinning temperature is 280℃,the diameter of spinneret hole is 1mm,the spinning voltage is 45 k V,the receiving distance is 7cm,the receiving area is 8×8cm2,the PET fiber diameter can be refined from the initial 11μm to 6.2μm,and the surface structure of the fiber is smooth.The diameter is evenly distributed.(2)PEG and PET have good compatibility and can be physically blended,and PEG will not occur pyrolysis reaction in the spinning process,so PET is a good viscosity reducing agent.When PEG is added into PET,the liquidity of the mixed melt can be improved,and the viscous characteristic of the mix can be reduced,resulting in a large decrease in fiber size.When the amount of PEG was 6wt%,the appearance of PET fiber was leveling and the minimum size was4.3μm,and the irregularity was 16%.With the up of the size refinement of PET fiber,fibers exhibit microscopic ductility along their axis,with the direction of chains within fibers also increasing.This leads to an increase in the force and stretch length of a single PET fiber,effectively improving its mechanical properties.(3)After the hot pressing treatment,the fibers of the melt electrostatic spinning fiber film have hot crystallization,and the bond points between the fibers increase,which makes the fiber film more dense,and effectively improves its mechanical properties.When the hot pressing temperature is 100℃,the elongation at break of the fiber film is the largest and 11.5%,and its breaking strength is 1.7MPa.Compared with the fiber without hot pressing treatment,the improvement of 62.6%;In addition,with the densification of the membrane structure,the pore size decreases and the pore size distribution Narrows,so it is expected to be applied in the field of filtration. |
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