20.500.12556/DKUM-94593 Hidrotermična razgradnja polikarbonata, ojačenega z ogljikovimi vlakni diplomsko delo visokošolskega strokovnega študijskega programa I. stopnje Hydrothermal degradation of carbon fiber reinforced polycarbonate Vse večja uporaba plastike vodi k vse večjemu številu odpadkov, ki prevečkrat pristanejo v naravi in jo onesnažujejo. Vse bolj alarmantno stanje kliče po hitrem iskanju rešitev, predvsem pri recikliranju uporabljene plastike in njeni ponovni uporabi. Eden izmed pogosto uporabljenih materialov je plastika ojačena z ogljikovimi vlakni, ki se uporablja predvsem v izdelavi prevoznih sredstev. Predstavnik te skupine materialov je tudi polikarbonat, ojačen z ogljikovimi vlakni. Namen diplomske naloge je bil z uporabo podkritične vode raziskati razgradnjo polikarbonata, ojačenega z ogljikovimi vlakni in analizirati sestavo pridobljenih produktov. Eksperimente smo izvedli v šaržnem reaktorju pri več različnih temperaturah (250 °C, 300 °C in 350 °C) in pri različnih časih (5, 15, 30, 60 in 120 min) in razmerju material voda 1:5. Produkte smo dobili v različnih fazah in sicer plinski, vodni, trdni in dietiletrski (DEE) fazi. Najprej smo analizirali izkoristke posamezne faze. Največji izkoristek trdne faze (90,5 %) smo določili pri temperaturi 250 °C in času 60 min, kar pomeni, da pri teh pogojih še nismo dosegli učinkovite razgradnje materiala. Najvišji izkoristek DEE faze (63,8 %) smo določili pri 300 °C in 30 min, ta se je nato pri nadaljnjih reakcijah s časom in temperaturo zniževal. Izkoristka plinske faze (19,2 %) in vodne faze ( 5,5 %) sta prav tako naraščala s časom in temperaturo in dosegla maksimum pri temperaturi 350 °C in 120 min. Za določitev komponent v plinski in DEE fazi smo izvedli GC-FID analizo. V DEE fazi smo določili bisefenol A, ki je največji delež (44,6 %) dosegel pri temperaturi 250 °C in času 60 min. Pomemben razgradni produkt je bil tudi fenol, ki je maksimum (57,5 %) dosegel pri temperaturi 350 °C in času 120 min. V plinski mešanici je bilo največ butena (v območju 16 - 70 %), sledila sta mu aceton, pri temperaturah 250 °C in 300 °C, ter propen pri temperaturi 350°C. S FTIR analizo smo analizirali trdne faze po razgradnji in ugotovili, da se z večanjem temperature in reakcijskega časa, v njej nahajajo le ogljikova vlakna, brez ostankov PC materiala. Z analizo vodne faze smo določili količino prisotnega ogljika, ki se je pri temperaturi 250 °C s podaljšanjem časa povečala (od 8,7 % do 9,9 %). Podobno se je pri temperaturi 300 °C koncentracija ogljika v vodni fazi do časa 30 min povečevala(od 12,9 % do19,1 %), nato pa se je začela zmanjševati. Pri temperaturi 350 °C pa se je vrednost ogljika s podaljševanjem časa reakcije zniževala (od 13,5 % do 5,7 %). Rezultati kažejo na to, da je hidrotermična razgradnja polikarbonata, ojačenega z ogljikovimi vlakni, obetajoča alternativna metoda recikliranja s katero lahko, ne le pridobimo ogljikova vlakna, temveč tudi druge uporabne razgradne produkte. The increasing use of plastic leads to more and more waste, which all too often ends up in nature and pollutes it. The increasingly alarming situation calls for urgent solutions, especially in the area of recycling and reuse of used plastics. One of the most commonly used materials is carbon fiber reinforced plastic, which is mainly used to produce various parts of transport vehicles. One representative of this material group is carbon fiber reinforced polycarbonate. The aim of the thesis was to investigate the degradation of carbon fiber reinforced polycarbonate using subcritical water and to analyze the composition of the obtained products. The experiments were carried out in a batch reactor at different temperatures (250 °C, 300 °C, and 350 °C), reaction times (5, 15, 30, 60 and 120 min), and a material/water ratio of 1:5. The products were obtained in different phases: gaseous, aqueous, solid, and in diethyl ether (DEE) phase. First, the yields of each phase were analyzed. The highest yield of the solid phase (90.5 %) was determined at a temperature of 250 °C and a reaction time of 60 minutes, which indicates that effective degradation of the material was not yet achieved under these conditions. The highest yield of the DEE phase (63.8 %) was observed at 300 °C and 30 minutes, after which it decreased with increasing reaction time and temperature. The yield of the gaseous (5.5 %) and aqueous phases (19.2 %) also increased with time and temperature and reached its maximum at 350 °C and 120 minutes. GC-FID analysis was performed to identify the components in the gas and DEE phases. Bisphenol A was detected in the DEE phase, reaching its highest yield (44.6 %) at 250 °C and 60 minutes. Phenol was also identified as an important degradation product, reaching a maximum (57.5 %) at 350 °C and 120 minutes. In the gas phase butene had the largest proportion (between 16 – 70 %), followed by acetone at 250 °C and 300 °C and propene at 350 °C.The solid phases after degradation were analyzed by FTIR and it was found that with increasing temperature and reaction time, only carbon fibers remained in the solid residue with no detectable traces of PC material. The aqueous phase was analyzed to determine the amount of dissolved carbon, which increased with reaction time at 250 °C (from 8.7 % to 9.9 %). Similarly, the carbon concentration in the aqueous phase increased at 300 °C for up to 30 minutes (from 12.9 % to 19.1 %) after which it began to decrease. At 350 °C, the carbon content decreased continuously with increasing reaction time (from 13.5 % to 5.7 %). The results show that hydrothermal degradation of carbon fiber reinforced polycarbonate is considered a promising alternative recycling method by which not only carbon fibers but also other useful degradation products can be recovered. polikarbonat hidrotermični postopki podkritična voda recikliranje ogljikova vlakna polycarbonate hydrothermal processes subcritical water recycling carbon fibres true true false [A. Zadravec] Slovenski jezik Angleški jezik Diplomsko delo/naloga 2025-08-22 08:44:51 2025-10-28 15:21:28 2025-11-05 03:11:43 0000-00-00 00:00:00 2025 0 Maribor 0 Maribor 1 spletni vir (1 datoteka PDF (VIII, 35 str.)) 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 66.092:678.7(043.2) 255798531 VS_Zadravec_Anja_2025.pdf VS_Zadravec_Anja_2025.pdf 1 C5ADEF580329B4B956D67234C7B7D318 ea9b54f6bc6cc1846e4ef3c68723ddb46809264250004e62e51db2e7c3d1fa68 d5369cf3-8903-11f0-82a8-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=197540 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0