Synthesis and evaluation of acoustic hybrid polyamide/silica nanoparticles fabricated by electrospinning method

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Synthesis and evaluation of acoustic hybrid polyamide/silica nanoparticles fabricated by electrospinning method

ارائه دهنده: Provider: Fatemeh ashtari maimand

اساتید راهنما: Supervisors: Dr.Hamid Esfahani

اساتید مشاور: Advisory Professors: Dr. Masoud Shafiee Motlagh

اساتید ممتحن یا داور: Examining professors or referees: Dr.Hasan Elmkhah-Dr.Shahab kazemi

زمان و تاریخ ارائه: Time and date of presentation: 2023

مکان ارائه: Place of presentation: Amfiteatr

چکیده: Abstract: The aim of this study was to improve the sound absorption behavior of polyurethane foam (PU) using electrospinning nylon6 nanofibers (PA6) and hybrid composite of nylon6 nanofibers-silica nanoparticles (PA6-SiO2) and nylon6-silver nanoparticles (PA6-Ag). For the synthesis of nanofibers, electrospinning method with constant collector was used, which is of interest to many researchers today, has some characteristics such as simplicity of work, cost-effectiveness and ability to synthesize fibers with diameters in the nanometer and micrometer size ranges. Field emission scanning electron microscopy (FESEM) and X-ray scattering (EDS) were used to investigate the size of nanofiber diameter, nanofiber morphology and chemical analysis, respectively. Transmission electron microscopy (TEM), was used to prove the presence of nanoparticles and how they are distributed in nanofiber substrate. Infrared spectroscopy analysis (FTIR), was used to investigate the molecular foundations of the assembled nanofibers using X-ray diffraction analysis (XRD), to investigate the crystalline structure of the nanofibers. Brunauer-Emmett-Teller analysis (BET), was used to investigate the porosity of nanofibers and tensile test was used to investigate the mechanical properties of nanofibers. Finally, impedance tube was used to investigate the acoustic absorption properties of nanofibers in the frequency range of 200 to 2000 Hz. In this study, the effect of various factors such as nanofiber morphology, coating thickness, porosity, and electrospinning nanofiber layering was investigated on sound absorption. First, polyurethane samples with single layer coating of nanofibers were investigated. Then, the multilayer coating of nanofibers was investigated, the results showed that average diameter sizes of PA6, PA6-SiO2 and PA6-Ag nanofibers were 177.1± 5, 181.9± 5 and 103 ± 1 nm respectively. It was also observed that silica nanoparticles cause uneven surface roughness of nanofiber surface. In the use of single layer coating made of nanofibers, the results of sound absorption coefficient showed no improvement and even decreased performance in the sound absorption behavior of polyurethane foam, but in the use of multilayer coating, the results of sound absorption coefficient improved dramatically in all samples. In general, it can be said that by increasing the thickness of the coating (using multilayer coating) and porosity of nanofibers, the absorption of sound increases. Placement of nylon 6 nanofibers with more porosity (20.868 m2g-1) against sound wave and nanofibers containing silica and silver nanoparticles under nylon6 nanofibers and on polyurethane foam The sound absorption coefficient of polyurethane foam from 0.43 to 0.636, 0.582 and 0.574, respectively, for multilayered foam samples (PA6, PA6-SiO2) and (PA6-Ag and PA6-SiO2 and PA6) and (PA6-Ag and PA6). In general, the exposure of layers with more porosity against the sound wave and the placement of layers containing nanoparticles with more roughness of fibers at the bottom and on polyurethane foam due to the greater absorption of sound waves by the structure with higher porosity and more friction of sound waves with the structure containing the tortuous paths created by nanoparticles, the overall absorption coefficient of the foam is improved

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