Priprava i karakterizacija PLA kompozita s grafitnim punilima

undergraduate thesis

• Title (english): Preparation and characterization of PLA composites with graphite fillers
• Author: Alan Badrov
• Mentor: Elvira Vidović (mentor)
• Committee member: Elvira Vidović (predsjednik povjerenstva)
• Committee member: Fabio Faraguna (član povjerenstva)
• Committee member: Domagoj Vrsaljko (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2015-09-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development

Abstract

U ovom radu istraživali su se kompozitni materijali na osnovi biorazgradivog polilaktida (PLA) ojačani grafitnim punilima: grafitne pahulje (A) i amorfni grafit (B). Kompoziti su se pripremali umješavanjem na Brabender gnjetalici (udio punila: 0,1, 0,5, 1 i 5 mas. %) i iz otopine (udio punila: 0,1 i 1 mas. %). Ispitivala su se i uspoređivala mehanička i toplinska svojstva čistog PLA i pripravljenih kompozita. Diferencijalnom pretražnom kalorimetrijom ispitivani su fazni prijelazi. Termogravimetrijskom analizom se ispitivala termička stabilnost uzoraka. Goniometrom se određivao kontaktni kut uzoraka sa vodom, formamidom i dijodometanom kao testnim kapljevinama, te je računata površinska energija pripravljenih materijala. Univerzalnom mehaničkom kidalicom su se određivala mehanička svojstva uzoraka. Određivana su vlačna čvrstoća, Youngov modul, te prekidno istezanje.
Karakterizacijom kompozitnih materijala ustanovljeno je da dodatkom punila u polilaktid možemo utjecati na njegova svojstva. DSC analizom je zabilježen utjecaj različitih metoda priprave i različitih punila na temperature staklastih prijelaza. Termogravimetrijska analiza je pokazala da dodatkom punila možemo poboljšati termičku stabilnost polilaktida. Mehanička svojstva kompozita bolja su u usporedbi s čistim PLA, zabilježene su veće vrijednosti Youngovog modula, naprezanja i prekidnog istezanja. Iz rezultata ispitivanja na goniometru nije se moglo dobiti jasno pravilo po kojem se mijenja kontaktni kut materijala, odnosno površinska svojstva materijala.

Abstract (english)

This work investigates composites of biodegradeable polylactide (PLA) reinforced with graphite fillers: graphite flakes (A) and amorphus graphite (B). Composites were prepared in a Brabender mixer (filler concetration: 0.1, 0.5, 1 and 5 wt. %) and by solution mixing (with 0.1and 1 wt. % of filler). Mechanical and thermal properties of pure polylactide and its composites were investigated. An insight into phase transition temperature and phase transition of the polymer were obtained by differental scanning calorimetry. The thermal stability of the samples was monitored by thermogravimetry. The contact angles of test liquids (water, formamied and diiodomethane) were determined by a goniometer after which the free surface energy was calculated. The universal testing machine was used to determine mechanical propertise of PLA and prepared composites. The tensile strenght, Young's modulus and elongation at break of the materials were determined.
Characterization of composite materials revealed that the addition of fillers to polylactide has different influence on some of its properties. The DSC method has shown influence of various preparation methods and different fillers on the glass transition temperature, which did not change significantly, though. Thermogravimetry has showed that the composites are more thermally stable than pure PLA. Composites have better mechanical properties such as higher Young's modulus, tensile strenght as well as elongation at break. Studies on the goniometer did not give a clear correlation between the type and concentration of filler in the composite and its surface properties.

• Keywords: polilaktid; kompozit; punilo; pahuljasti grafit; amorfni grafit
• Keywords (english): polylactide; composite; filler; graphite flakes; amorphus graphite
• Language: croatian
• URN:NBN: urn:nbn:hr:149:843747
• Study programme: Title: Environmental Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Repository: Repository of Faculty of Chemical Engineering and Technology University of Zagreb
• Created on: 2016-11-25 12:14:03