Characterization af electrospun PAN submicron fibers
Authors
Thomsen, Anders Noel ; Scherer, Mathias Agersnap
Term
4. semester
Education
Publication year
2016
Submitted on
2016-06-01
Pages
119
Abstract
This thesis investigates the fabrication, characterization, and application of electrospun polyacrylonitrile (PAN) submicron fibers produced from PAN dissolved in N,N-dimethylformamide (DMF). A new electrospinning setup was commissioned through preliminary trials and a literature study, after which fibers were spun from three solution concentrations (6, 8, and 10 wt%). Uniform fibers were obtained at all concentrations with diameters from 283 to 1145 nm (lowest measured 283 ± 82 nm), and production rate decreased at lower concentrations. The fibers were characterized by scanning electron microscopy (morphology and diameter), polarized Raman spectroscopy (molecular orientation), X-ray diffraction (crystallinity), thermogravimetric analysis (residual DMF), and tensile testing (mechanical response). Results showed increasing molecular orientation with decreasing fiber diameter, approximately constant crystallinity around 50%, and about 5% residual DMF across all samples. Tensile tests indicated a trend of higher strength at smaller diameters, though the data were noisy due to a limited number of specimens. Application was evaluated in fiber-reinforced laminate composites using double cantilever beam tests to assess delamination resistance; no clear improvement was observed compared to references, possibly due to an insufficient added fiber amount. The thesis thus maps process–structure–property relationships for electrospun PAN fibers within the studied range.
Dette speciale undersøger fabrikation, karakterisering og anvendelse af elektrospundne polyacrylonitril (PAN) submikronfibre fremstillet fra PAN opløst i N,N-dimethylformamid (DMF). En ny elektrospinningsopstilling blev indkørt via indledende forsøg og litteraturstudie, hvorefter fibre blev spundet fra tre opløsningskoncentrationer (6, 8 og 10 vægt-%). Ensartede fibre blev opnået ved alle koncentrationer med diametre fra 283 til 1145 nm (laveste målte 283 ± 82 nm), og produktionsmængden faldt ved lavere koncentration. Fibrene blev karakteriseret med scanning elektronmikroskopi (morfologi og diameter), polariseret Raman-spektroskopi (molekylær orientering), røntgendiffraktion (krystallinitet), termogravimetrisk analyse (residualt DMF) og trækforsøg (mekanisk respons). Resultaterne viste øget molekylær orientering ved faldende fiberdiameter, omtrent konstant krystallinitet omkring 50 % og ca. 5 % residual DMF for alle prøver. Trækforsøgene indikerede en tendens til højere styrke ved mindre diameter, men data var støjpræget på grund af få testemner. Anvendeligheden blev vurderet i fiberforstærkede laminatkompositter via double cantilever beam-forsøg for at undersøge delaminationshæmning; her blev ingen tydelig forbedring observeret i forhold til referenceprøverne, muligvis fordi den tilsatte fibermængde var for lav. Specialet sammenfatter således proces-, struktur- og egenskabsrelationer for elektrospundne PAN-fibre i det undersøgte område.
[This apstract has been generated with the help of AI directly from the project full text]
Keywords