20.500.12556/DKUM-99481 Razgradnja polikarbonata (PC) v nadkritičnih ketonih diplomsko delo univerzitetnega študijskega programa I. stopnje Degradation of polycarbonate (PC) in supercritical ketones Polikarbonat (PC) je eden najpomembnejših tehničnih termoplastov, katerega vse večja uporaba povzroča tudi naraščajoče količine odpadnega materiala. Namen diplomskega dela je bil preučiti depolimerizacijo polikarbonata v nadkritičnih ketonih ter ovrednotiti vpliv temperature, reakcijskega časa, vrste topila in dodatka vode na dobit tekoče faze ter sestavo nastalih produktov. Eksperimenti so bili izvedeni v visokotlačnem šaržnem reaktorju z uporabo acetona, metil etil ketona (MEK), njunih mešanic z vodo in čiste vode. Nastale produkte smo analizirali z metodo plinske kromatografije z detektorjem plamenske ionizacije (GC-FID), trdne ostanke pa karakterizirali s Fourierjevo transformacijsko infrardečo spektroskopijo (FTIR). Rezultati so pokazali, da dodatek vode, temperatura in reakcijski čas pomembno vplivajo na dobit tekoče faze. Največji vpliv na učinkovitost procesa depolimerizacije je imel dodatek vode. Tako je bila že pri najnižji temperaturi (300 °C) in najkrajšem reakcijskem času (1 h) pri 50 % vodni raztopini acetona dobit tekoče faze 95,3 % in pri 50 % vodni raztopini MEK 96,6 %. To je več kot 11-krat več kot v čistem acetonu, kjer je bil pri teh pogojih 8,5 %, in čistem MEK, kjer je bil 7,6 %. Pri teh pogojih je bil dobit tekoče faze v čisti vodi in vodnih raztopinah večji kot v čistih ketonih pri najvišji temperaturi (350 °C) in istem reakcijskem času (1 h), kjer je bil pri acetonu 61,2 % in pri MEK 75,5 %. GC-FID analiza je potrdila prisotnost bisfenola A (BPA), fenola in 4-izopropenilfenola kot produktov razgradnje. Vpliv temperature, reakcijskega časa, vrste topila in dodatka vode na sestavo produktov razgradnje je podoben njihovemu vplivu na dobit tekoče faze. Glavni produkt razgradnje je bil BPA, njegov največji masni delež pa je bil določen za depolimerizacijo z 50 % vodnimi raztopinami ketonov (40,5 % za MEK:H2O in 38,1 % za aceton:H2O) pri temperaturi 300 °C in reakcijskem času 1 h in je bil kar za 3-5 krat višji kot pri reakcijah v čistih ketonih pri enakih pogojih. Rezultati potrjujejo, da so nadkritični ketoni, zlasti v kombinaciji z vodo, učinkoviti reakcijski mediji za kemijsko recikliranje polikarbonata in predstavljajo obetavno možnost za ponovno pridobivanje monomernih produktov z visoko dodano vrednostjo. Polycarbonate (PC) is one of the most important engineering thermoplastics, and its increasing use is also leading to growing amounts of waste material. The purpose of this thesis was to study the depolymerization of polycarbonate in supercritical ketones and to evaluate the effect of temperature, reaction time, solvent type, and water addition on the liquid-phase yield and the composition of the resulting products. The experiments were conducted in a high-pressure batch reactor using acetone, methyl ethyl ketone (MEK), mixtures of these solvents with water, and pure water. The resulting products were analyzed by gas chromatography with a flame ionization detector (GC-FID), and the solid residues were characterized by Fourier transform infrared spectroscopy (FTIR). The results showed that the addition of water, temperature, and reaction time significantly influence the liquid-phase yield. The addition of water had the greatest effect on the efficiency of the depolymerization process. Thus, even at the lowest temperature (300 °C) and the shortest reaction time (1 h), the liquid-phase yield was 95.3 % in a 50 % aqueous acetone solution and 96.6 % in a 50 % aqueous MEK solution. This is more than 11 times higher than in pure acetone, where it was 8.5 % under these conditions, and in pure MEK, where it was 7.6 %. Under these conditions, the depolymerization rate in pure water and aqueous solutions was higher than in pure ketones at the highest temperature (350 °C) and the same reaction time (1 h), where it was 61.2% for acetone and 75.5% for MEK. GC-FID analysis confirmed the presence of bisphenol A (BPA), phenol, and 4-isopropenylphenol as degradation products. The effect of temperature, reaction time, solvent type, and water addition on the composition of the degradation products is similar to their effect on the depolymerization rate. The main degradation product was BPA, and its highest mass fraction was determined for depolymerization with 50% aqueous solutions of ketones (40.5% for MEK: H2O and 38.1% for acetone:H2O) at a temperature of 300 °C and a reaction time of 1 h, and was as much as 3 to 5 times higher than for reactions in pure ketones under the same conditions. The results confirm that supercritical ketones, particularly in combination with water, are effective reaction media for the chemical recycling of polycarbonate and represent a promising option for the recovery of high-value-added monomer products. polikarbonat aceton metil etil keton nadkritični ketoni dobit tekoče faze polycarbonate acetone methyl ethyl ketone supercritical ketones liquid-phase yield true true false [A. Agrež] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2026-08-18 12:03:37 2026-09-16 11:07:26 2026-09-26 03:10:13 0000-00-00 00:00:00 2026 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (VIII, 36 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 66.095.268:678.073(043.2) 292479491 UN_Agrez_Anja_2026.pdf UN_Agrez_Anja_2026.pdf 1 874FBCBC6817ECBA641EE12B1B0C406C 84bb6180eeeb17ce0f100a5a4b8e891e90756d931ee7d069bb50c7f1a52ef716 1ace5ef0-a6e4-11f1-aef5-00155d0001be https://dk.um.si/Dokument.php?lang=slv&id=211345 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0