Preparation and characterization PEO10/Cloisite 15A i PEO10/Cloisite 15A/LiBoB nanocomposites : diploma thesis

Abstract

U ovom radu se ispitivao utjecaj punila Cloisite15A (15A) na kristalnost, toplinske prijelaze (staklište, talište i kristalište), toplinsku stabilnost, strukturu poli(etilen-oksida) (PEO) molekulske mase ̅̅̅̅ = 1 000 000 (PEO10) i ionsku provodnost. Litijev bis(oksalato)borat (LiBOB) je dodan u omjeru 1:8 (Li : kisik etera) s ciljem ostvarivanja dovoljne koncentracije nositelja naboja. Polimerni nanokompoziti su pripravljeni u dvije serije. Prva serija je dobivena miješanjem PEO10 s punilom 15A u odgovarajućim omjerima, metodom interkalacije iz taljevine. Pripravljeni su uzorci s masenim omjerima PEO10/15A: 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 i 10/90. Druga serija je dobivena miješanjem PEO10 s punilom 15A u odgovarajućim omjerima uz dodatak LiBOB-a, metodom interkalacije iz taljevine. Pripravljeni su uzorci s masenim omjerima PEO10/15A/LiBOB: 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 i 10/90. Primjenom diferencijalne pretražne kalorimetrije (DSC) je ispitivan utjecaj 15A na toplinske prijelaze (staklište, talište i kristalište) i kristalnost PEO10. Uočeno je da dodatak punila 15A smanjuje kristalište PEO10, ali značajnije ne utječe na staklište i talište PEO10. Dodatak 15A smanjuje topline taljenja i kristalizacije PEO10 što upućuje na smanjenje stupnja kristalnosti PEO10. Pomoću termogravimetrijske analize (TGA) je ispitivan utjecaj 15A na toplinsku stabilnost PEO10. Utvrđeno je da se temperature početka razgradnje i temperature pri maksimalnoj brzini razgradnje smanjuju s povećanjem mas. % 15A. Iz toga se zaključilo da dodatak punila 15A smanjuje toplinsku postojanost PEO10. Pomoću infracrvene spektroskopije s Fourierovom transformacijom (FT-IR) je ispitivan utjecaj 15A na strukturu PEO10. Utvrđeno je da dodatak 15A utječe na konformaciju PEO10, tj. da dolazi do iskrivljenja spiralne konformacije PEO10. To je ukazalo na promjenu kristalnosti kod PEO10 te je to u skladu s rezultatima dobivenim metodom diferencijalne pretražne kalorimetrije. Pomoću elektrokemijske impedancijske spektroskopije (EIS) je ispitivan utjecaj 15A na ionsku provodnost PEO10. Utvrđeno je da ionska provodnost nanokompozita pokazuje maksimalnu vrijednost pri 10 mas % 15A, što upućuje na zaključak da stupanj kristalnosti PEO10 nije jedini faktor koji utječe na ionsku provodnost nanokompozita.This paper examines the impact of Cloisite15A filler on crystallinity, thermal transition (glass transition temperature, melting and crystallization temperature), thermal stability, structure of poly(ethylene oxide) (PEO) (molecular mass, ̅̅̅̅ =1 000 000) (PEO10) and ionic conductivity. Lithium bis(oxalato) borate (LiBOB) was added in a ratio of 1:8 (Li : oxygen of ether) to achieve a sufficient concentration of the charge carrier. Two series of polymer nanocomposites were prepared. The first one was obtained by mixing PEO10 with 15A filler at the appropriate ratios, using a melt intercalation method. Samples with mass ratios of PEO10/15A: 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 and 10/90 were prepared. The second one was obtained by mixing PEO10 with 15A filler in the respective ratios with the addition of LiBOB by a melt intercalation method. Samples with mass ratios of PEO10/15A/LiBOB: 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 and 10/90 were prepared. Differential scanning calorimetry (DSC) investigated the influence of 15A on the thermal transitions (glass transition, melting and crystallization) and crystallinity of PEO10. It was noted that the addition of 15A reduces the temperature of crystallization, but does not significantly affect PEO10 glass transition temperature and melting point temperature. Melting and crystallization entalphy reduces with the addition of 15A which suggests the reduction of the degree of crystallity of PEO10. Thermogravimetric analysis (TGA) investigated the influence of 15A on the thermal stability of PEO10. It was found that the starting temperatures of the decomposition (T o ) and the temperatures at the maximum decomposition rate (T max ) decrease with increasing mass. % of 15A. It was concluded that the addition of filler 15A reduces the thermal stability of PEO10. Fourier transform infrared spectroscopy (FT-IR) investigated the influence of 15A on the PEO10 structure. It was found that the addition of 15A influences the conformation of PEO10, that there is a distortion of its helical conformation. This indicated a change in crystallinity in PEO10 and is consistent with results obtained by differential scanning calorimetry (DSC). Electrochemical impedance spectroscopy (EIS) investigated the influence of 15A on ionic conductivity of PEO10. It was found that the sample with the addition of 10 wt. % shows maximum ionic conductivity, which suggest that the degree of crystallinity is not the only that affects the ionic conductivity of the nanocomposite

    Similar works