Priprava i karakterizacija ABS kompozita ojačanih vlaknima brnistre

master's thesis

• Title (english): Preparation and characterization of ABS composites reinforced with broom fibres
• Author: Ana Maria Ćosić
• Mentor: Emi Govorčin Bajsić (mentor)
• Committee member: Emi Govorčin Bajsić (predsjednik povjerenstva)
• Committee member: Ljerka Kratofil Krehula (član povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2025-02-21, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

U ovom radu pripravljeni su i analizirani ABS kompoziti s vlaknima brnistre u udjelima od 5, 10, 15 i 20 mas.%. Čisti ABS i kompoziti pripremljeni su u gnjetilici Brabender, nakon čega je uslijedilo prešanje na hidrauličnoj preši i karakterizacija. Korištene tehnike karakterizacije su diferencijalna pretražna kalorimetrija (DSC), termogravimetrijska analiza (TGA), infracrvena spektroskopija s Fourierovim transformacijama (FTIR) te test bubrenja. FTIR analiza nije pokazala postojanje kovalentih veza između vlakana brnistre i ABS-a. Prema DSC analizi, dodatak vlakana smanjuje temperaturu staklastog prijelaza (Tg) butadienske faze kod kompozita s 5 mas.% vlakana, dok se daljnjim povećanjem udjela vlakana Tg povećava, što je povezano s djelovanjem vlakana kao fizičkih barijera u pokretanju polimernih lanaca. Entalpija kristalizacije (ΔHc1) i temperatura kristalizacije (Tc1) smanjuju se s povećanjem udjela vlakana, jer vlakna otežavaju migraciju i difuziju polimernih lanaca prema površini rastućih kristala, smanjujući tako kristalnost kompozita. TG analiza pokazuje povećanje početne temperature razgradnje (T5%) u odnosu na čisti ABS do kompozita s 10 mas.%, nakon čega dolazi do opadanja. Temperaturni interval razgradnje (ΔT) snižava se do kompozita
s 10 mas.%, nakon čega raste s povećanjem udjela vlakana. Najveći gubitak mase pokazuje čisti ABS, a gubitak se smanjuje povećanjem udjela vlakana, dok se količina ostatka pri
600 °C povećava. Rezultati analize bubrenja pokazuju da stupanj bubrenja (α) raste s povećanjem udjela vlakana brnistre zbog povećanja hidrofilnosti kompozita.

Abstract (english)

In this study, ABS composites reinforced with Spartium junceum L. fibers were prepared and characterized in content of 5, 10, 15, and 20 wt. %. The neat ABS and the composites were prepared in a Brabender mixer, followed by compression with a hydraulic press and then characterized. The techniques used were differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and swelling test. The FTIR analysis did not show the presence of covalent bonds between the Spartium junceum L. fibers and ABS polymer. According to the DSC analysis, the addition of fibers reduces the glass transition temperature (Tg) of the butadiene phase in the composite with 5 wt.% fibers, while further increasing the fiber content results in an increase in Tg, which is associated with the role of fibers as physical barriers to polymer chain mobility. The enthalpy of crystallization (ΔHc1) and the crystallization temperature (Tc1) decrease with increasing fiber content, as the fibers hinder the migration and diffusion of polymer chains to the growing crystal surfaces, reducing the crystallinity of the composites. The TGA results show an increase in the initial decomposition temperature (T5%) compared to the neat ABS, up to the composite with 10 wt.% fibers, after which it decreases. The thermal degradation temperature range (ΔT) decreases up to the 10% fiber content, after which it increases with higher fiber content. The highest mass loss occurs for the neat ABS, and the loss decreases with increasing fiber content, while the amount of residue at 600°C increases. The swelling analysis shows that the degree of swelling (α) increases with the fiber content due to the increased hydrophilicity of the composites.

• Keywords: ABS; brnistra; kompozit; DSC; FTIR; TGA
• Keywords (english): ABS; Spartium junceum L.; composite; DSC; FTIR; TGA
• Language: croatian
• URN:NBN: urn:nbn:hr:149:577513
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva (sveučilišni/a magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2025-02-28 11:21:49