Preparation And Sound Absorption Properties Of Modified PVA Nanofiber Membrane Composites

With the rapid development of industrialization in modern society,noise pollution was listed as the four major pollution with air pollution,water pollution and solid waste pollution.Noise affects people’s health and daily life.The sound absorbing materials is one of the most direct and effective ways to reduce noise.Nanofibers can effectively reduce noise because of small diameter and large specific surface area,which are gradually used in the field of acoustics.The traditional sound absorbing material combined with nanofiber membrane obtain excellent sound absorption performance,the appearance and microstructure of the nanofiber membrane also affects the sound absorption performance of the composite material.The polyvinyl alcohol（PVA）nanofibers are straight and smooth,and the surface of the film is even and flat.Modifying the surface of PVA nanofiber membrane can improve the sound absorption performance.In this paper,a series of polyvinyl alcohol（PVA）-based nanofiber membranes were prepared by spiral-type electrospinning machine.The nanofiber membranes were modified by blending and adding nanoparticles to improve their sound absorption performance.Then the nanofiber membranes were composited with the needle-punched nonwoven fabric to investigate the sound absorption properties of the composite materials with different structures.In order to change the fiber morphology and structure of the PVA nanofiber membrane,firstly,the blend nanofiber membranes were prepared by electrospinning,spin solution contained 10%PVA and 3%polyoxyethylene（PEO）,and the blend ratio were 100/0,90/10,80/20,70/30 and 0/100.The prepared PVA/PEO nanofiber membranes were combined with needle-punched nonwoven fabrics in different ways to explore the effects of different blending ratios on the morphology of nanofiber membranes and the sound absorption properties of composites.The polymer particles have a large specific surface area,which affects the structure of the fiber during the electrospinning process,thereby changing the vibration form of the nanofiber and affecting the sound absorption performance of the material.Secondly,added graphene nanosheets（GNs）and graphene oxide（GO）with mass fractions of 0.5%,1.0%,and 1.5%to the PVA/PEO spinning solution,explored the addition of different content of GNs and GO on the morphology of nanofiber membranes,and combined with needle-punched nonwoven fabric to explore the sound absorption properties of different structural composites.Finally,added TiO₂ nanoparticles to PVA/PEO/GNs and PVA/PEO/GO spin solution,a series of nanofiber membranes with mass fractions of 1.0%,3.0%,and 5.0%TiO₂ were prepared by orthogonal test.The sound absorption properties of composites of nanofiber membranes and needle-punched nonwoven fabrics were investigated,the effects of adding two kinds of nanoparticles on the morphology of nanofiber membranes and the sound absorption properties of composites were investigated.The study have shown that after blending PVA with PEO,the fiber irregularity and the surface irregularity of nanofiber membrane increased.When the nanofiber membrane was used as the sound receiving surface,the irregularity of the nanofiber membrane’s surface can help to increase the absorption range of the composite material for sound waves.The method of compositing can also affect the sound absorption of the composite material,the average coefficient of the material’s sound absorption gradually increased when the nonwoven fabric moves from the front layer to the middle layer and the back layer in the composite material.After adding GNs,the diameter of the nanofiber and the average aperture reduced,the morphology of the membrane’s surface didn’t change obviously.The diameter of the nanofiber was reduced the surface of the nanofiber membrane became flat after adding GO.When the 2 mm nanofiber membrane was used as the sound receiving surface,the average sound absorption coefficient of PVA/PEO/GNs（0.5%）composite is up to 0.47.The PVA/PEO/GO nanofiber membrane and the needle-punched non-woven composite material with sandwich structure had excellent sound absorption performance,and the absorption peak gradually becomes larger and shifts toward the intermediate frequency direction with the increase of the GO’s quality fraction.Agglomeration occurs after the addition of TiO₂ in the spinning solution.The PVA/PEO/GNs/TiO₂ composites performance good sound absorption in the range of 1000～3000 Hz.The composite materials exhibit better sound absorption performance when both GNs and TiO₂ are at the level of 1 and 2.The sound absorption performance of PVA/PEO/GO/TiO₂ composites is significantly improved in 500～1000 Hz,when both GO and TiO₂ are at level 2,the average sound absorption coefficient of the composite material reached 0.44.Blending or adding nanoparticles can change the appearance and micro-modification of the nanofiber membrane,so that the sound absorption performance of the composite material can be improved and and the research content of electrospun nanofiber materials can be enriched.