Diferenčna dinamična kalorimetrija in termogravimetrična analiza kot orodji vrednotenja študije vpliva ponovne predelave/mehanskega recikliranja kopolimera poli mlečne kisline (PLeA)

Semenič, Dona

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Title:	Diferenčna dinamična kalorimetrija in termogravimetrična analiza kot orodji vrednotenja študije vpliva ponovne predelave/mehanskega recikliranja kopolimera poli mlečne kisline (PLeA)
Authors:	ID Semenič, Dona (Author) ID Stergar, Janja (Mentor) More about this mentor... ID Pušnik Črešnar, Klementina (Comentor)
Files:	UN_Semenic_Dona_2026.pdf (6,31 MB) MD5: 4EA5ADF777C6FCD969659FF71CEC27DA
Language:	Slovenian
Work type:	Bachelor thesis/paper
Typology:	2.11 - Undergraduate Thesis
Organization:	FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:	V diplomskem delu smo preučevali vpliv večkratne ponovne predelave oziroma mehanskega recikliranja na termične lastnosti in kristaliničnost kopolimera poli(L-laktid-ko-etilen adipat) (PLeA). Namen raziskave je bil ovrednotiti vpliv ponavljajočih se ciklov ekstruzije na termično stabilnost in kristalizacijsko obnašanje PLeA ter rezultate primerjati z rezultati za PLA. Vzorce smo do petnajstkrat ponovno predelali z ekstruzijo, njihove lastnosti pa smo analizirali z diferenčno dinamično kalorimetrijo (DSC) in termogravimetrično analizo (TGA). Izvedli smo dinamične in izotermne meritve. Rezultati DSC-meritev so pokazali, da se je pri PLeA z večkratno predelavo temperatura hladne kristalizacije na splošno zniževala, spremenili pa sta se tudi temperatura steklastega prehoda in temperatura tališča. Ocenjena stopnja kristaliničnosti PLA-segmentov v PLeA se je med posameznimi cikli spreminjala, pri poznejših ciklih pa je ponovno dosegala vrednosti, primerljive z referenčnim vzorcem. Rezultati so tako pokazali spremembe kristalizacijskega obnašanja PLeA med ponovno predelavo. Pri PLA tako izrazitih sprememb nismo opazili. TGA-meritve so pokazale večjo občutljivost PLeA na ponovno predelavo. Temperature visokotemperaturnih maksimumov na DTG-krivulji PLeA so se na splošno zniževale, medtem ko je temperatura glavnega maksimuma na DTG-krivulji PLA ostala razmeroma stabilna. Tudi izotermne TGA-meritve so pokazale bistveno večjo hitrost izgube mase pri PLeA kot pri PLA. Rezultati so pokazali, da je večkratna ponovna predelava vplivala na kristalizacijsko obnašanje in termično stabilnost PLeA, pri čemer spremembe niso bile linearno odvisne od števila ciklov.
Keywords:	PLeA, PLA, mehansko recikliranje, diferenčna dinamična kalorimetrija, termogravimetrična analiza, kristaliničnost
Place of publishing:	Maribor
Year of publishing:	2026
PID:	20.500.12556/DKUM-99949
Publication date in DKUM:	14.09.2026
Views:	297
Downloads:	17
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Categories:	KTFMB - FKKT
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Licences

License:	CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

Link:	http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:	The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:	31.08.2026

Secondary language

Language:	English
Title:	Differential Scanning Calorimetry and Thermogravimetric Analysis as Tools for Evaluating the Study of the Effects of Reprocessing/Mechanical Recycling of the Polylactic Acid Copolymer (PLeA)
Abstract:	In this bachelor’s thesis, we investigated the effect of repeated reprocessing or mechanical recycling, on the thermal properties and crystallinity of poly(L-lactide-co-ethylene adipate) (PLeA). The aim of the study was to evaluate the effect of repeated extrusion cycles on the thermal stability and crystallization behaviour of PLeA and to compare the results with those obtained for PLA. The samples were reprocessed by extrusion up to fifteen times, and their properties were analysed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Both dynamic and isothermal measurements were performed. The DSC results showed that, with repeated reprocessing, the cold crystallization temperature of PLeA generally decreased, while changes were also observed in the glass transition temperature and melting temperature. The estimated degree of crystallinity of the PLA segments in PLeA varied between individual cycles and, in the later cycles, again reached values comparable to that of the reference sample. The results therefore showed changes in the crystallization behaviour of PLeA during repeated reprocessing. No similarly pronounced changes were observed for PLA. The TGA results showed that PLeA was more sensitive to repeated reprocessing. The temperatures of the high-temperature maxima on the DTG curve of PLeA generally decreased, while the temperature of the main maximum on the DTG curve of PLA remained relatively stable. The isothermal TGA measurements also showed a significantly higher mass-loss rate for PLeA than for PLA. The results showed that repeated reprocessing affected the crystallization behaviour and thermal stability of PLeA, although the changes were not linearly dependent on the number of cycles.
Keywords:	PLeA, PLA, mechanical recycling, differential scanning calorimetry, thermogravimetric analysis, crystallinity

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