| With the improvement of people’s living material level,people have high requirements for taking warm materials.Although the traditional warm keeping clothing can play a certain role in heat preservation,it is too thick,which makes the human body not beautiful and even inconvenient to move,and has been gradually eliminated by the market.The existing synthetic fiber on the market is also due to its diameter(>10μm)too large,it is difficult to achieve lower volume density and higher warmth retention.Although the existing electrospinning technology can solve the problem of fiber diameter and meet the requirements of light weight and large specific surface area,its warmth retention is general due to its compact stacking,thin thickness and inability to store more static air.Air-jet spinning is a technology that uses high-speed air flow to elongate and refine the solution,and finally solidify it into fiber.The technology has the advantages of wide raw material selectivity,short process flow and easy batch production.In addition,the prepared fiber aggregate has the advantages of 3D bending,high porosity,fluffy softness and low volume density,showing great application potential in the field of warm insulation.However,the mechanical properties of most fiber sponges are very poor,which is easy to cause collapse and lead to poor recovery.Therefore,the preparation of lightweight,fluffy,stable mechanical structure and ultrafine fiber sponges as warm materials has great commercial application value.The main research contents are as follows:(1)In order to solve the problem of dense structure of ultrafine materials,fiber sponges were successfully prepared with PVA,PSU,PAN,PS as raw materials under the drafting effect of high-speed hot air flow.The test shows that PS fiber sponges has lower volume density 14.31 mg/cm~3 and higher mechanical properties 83.7 k Pa.On this basis,the effects of solution concentration and spinning pressure on fiber morphology and structure were further discussed.The test showed that when the concentration was 20 wt%,the air pressure was 0.2 MPa,the fiber morphology is better and the thermal conductivity is 21.63 m W/m·K.(2)In order to improve the mechanical properties of the fiber sponges,the elastomer polyurethane(PU)was added into the polymer PS to form a PS/PU two-component fiber sponges with a 3D structure.When the PS/PU content ratio was10:4,the sponges had good fluffy structure and the tensile fracture strength was203.7 k Pa.In order to further stabilize the fluffy structure of PS/PU and improve the mechanical properties,Trimethylolpropane tris(2-methyl-1-aziridine propionate)crosslinker(TTMA)is added.The 3D fiber sponges with network structure was successfully prepared by thermal crosslinking process.When the content of TTMA is10 wt%,the tensile breaking strength of sponges was 398.5 k Pa,and it still showed excellent resilience after 100 cycles of compression.Its volume density is about33.32 mg/cm~3,and the corresponding porosity is 96.96%.In order to test the service life of the sponges,the effect of washing period on the structure and mechanical properties of PS/PU/TTMA sponges were studied.The results showed that after four washing cycles,the fibers were still sparsely distributed,the volume density increased from 33.28 to 34.12 mg/cm~3,and the porosity decreased from 96.97 to96.90%,the breaking strength and elongation after water washing still remain at about 380 kPa and 31.8%,the contact angle remained around 136°,the compression curve can be closed after water washing,and the thermal conductivity was 30.64m W/m·K at room temperature.(3)In order to reduce the heat loss of the human body mechanism in cold environment,this study introduced the light-absorbing material zirconium carbide nanoparticles(Zr C NPs)into the crosslinked fiber sponges PS/PU,giving them excellent photothermal conversion function and providing additional heat for the human body.This chapter mainly explores the effect of Zr C NPs addition on the morphology,tensile property,compression resilience,fluffy structure,thermal insulation,photothermal conversion function and water resistance of PS/PU/TTMA fiber sponges.The tests showed that with the increase of Zr C NPs content,the particles on the surface of PS/PU/TTMA fiber became more numerous and the size became larger,but the 3D network structure of the sponges did not change significantly.When the content of Zr C NPs was 12%,the tensile stress of the fiber sponges could reach 375 k Pa,the volume density was 40.43 mg/cm~3,the porosity was 96.51%,and only slight plastic deformation after 100 cycles of compression,and the thermal conductivity at room temperature was stable at about 32 m W/m·K.In addition,after 10 min of irradiation by the sunlight simulator,the surface temperature of the sponges increased to 71.5°C,showing excellent photothermal conversion effect.At the same time,it also has good hydrophobic property of 139.5°. |
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