Toplinska stabilnost i viskoelastična svojstva PLA/TPU mješavina

master's thesis

• Title (english): Thermal stability and viscoelastic properties of PLA/TPU blends
• Author: Iva Šadura
• Mentor: Emi Govorčin Bajsić (mentor)
• Committee member: Emi Govorčin Bajsić (predsjednik povjerenstva)
• Committee member: Ljerka Kratofil Krehula (član povjerenstva)
• Committee member: Lidija Furač (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Polilaktid (PLA) je komercijalni biorazgradljivi termoplast koji se može dobiti iz bioizvora što ga čini potencijalnom ekološkom alternativom za polimere na bazi nafte. Njegovu primjenu ograničuje niska žilavost koja se nastoji povećati miješanjem s termoplastičnim poliuretanom (TPU). TPU je elastičan polimer dobrih mehaničkih svojstava. U ovom radu su u Brabender gnjetilici pripravljeni uzorci čistih PLA i TPU te PLA/TPU mješavina različitih masenih udjela (80/20, 60/40, 50/50, 40/60, 20/80). Toplinska stabilnost čistih polimera i PLA/TPU mješavina ispitana je termogravimetrijskom analizom (TGA), dok su viskoelastična svojstva određena dinamičko mehaničkom analizom (DMA). Rendgenskom difrakcijskom analizom ispitana je morfološka struktura čistih polimera i PLA/TPU mješavina. Otpornost uzoraka prema destiliranoj vodi određena je testom bubrenja. Termogravimetrijskom analizom utvrđeno je da je PLA toplinski stabilniji od čistog TPU jer njegova razgradnja započinje na višim temperaturama. Dodatkom TPU-a u PLA smanjuje se toplinska stabilnost PLA/TPU mješavina. Iz rezultata dinamičko mehaničke analize zaključeno je da su PLA/TPU mješavine djelomično mješljive. Ispitivanjem bubrenja utvrđeno je da su PLA i TPU te njihove mješavine hidrofobni materijali koji neznatno bubre u destiliranoj vodi. Rezultati XRD analize pokazali su da je PLA amorfne strukture, dok TPU ima amorfnu i kristalnu fazu u strukturi.

Abstract (english)

Polylactide (PLA) is a commercial biodegradable thermoplastic material which can be obtained from biosources, because of that PLA is potential ecological alternative to petroleum-based polymers. Its application is limited by its low toughness, which can be increased by mixing PLA with thermoplastic polyurethane (TPU). TPU is an elastic polymer with good mechanical properties. Samples of the neat PLA and TPU and PLA/TPU blends with different content (80/20, 60/40, 50/50, 40/60, 20/80) were prepared in the Brabender mixer. Thermal stability of the neat PLA and TPU as well as PLA/TPU blends was investigated by thermogravimetric analysis (TGA), while viscoelastic properties were determined by dynamic mechanical analysis (DMA). The morphological structure of the neat polymers and PLA/TPU blends was obtained by X-ray diffraction analysis. The resistance of the samples to the distilled water was determined by the swelling test. Results of TGA measurements confirmed that the neat PLA is thermally more stable than the neat TPU because of the higher decomposition temperature. Thermal stability of PLA/TPU blends in the nitrogen atmosphere decreased with addition of TPU. According to DMA results the PLA/TPU blends are partially miscible. The swelling test revealed that PLA, TPU and PLA/TPU blends are hydrophobic materials and that slightly swell in distilled water. Results of XRD analysis showed that PLA has an amorphous structure, while TPU has amorphous and crystalline phases in the structure.

• Keywords: polilaktid (PLA); termoplastični poliuretan (TPU); polimerne mješavine; toplinska stabilnost; viskoleastična svojstva; morfološka struktura
• Keywords (english): polylactide (PLA); thermoplastic polyurethane (TPU); polymer blends; thermal stability; viscoelastic properties; morphological structure
• Language: croatian
• URN:NBN: urn:nbn:hr:149:533349
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2022-09-30
• Created on: 2023-03-31 10:25:28