Title Priprema i toplinska karakterizacija kompozita PLA/otpad taloga kave Title (english) Preparation and thermal characterization of PLA/spent coffee grounds composites Author Ema Čemerika Mentor Vesna Ocelić Bulatović (mentor)Committee member Vesna Ocelić Bulatović (predsjednik povjerenstva)Committee member Krunoslav Žižek (član povjerenstva)Committee member Dajana Kučić Grgić (član povjerenstva)Granter University of Zagreb Defense date and country 2022-09-14, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Zbog sve većeg problema onečišćenja okoliša te zbrinjavanja otpada, posljednjih nekoliko godina naglasak se stavlja na koncept zero waste. Sve više industrijskih pogona zamjenjuje koncept linearne ekonomije s kružnom ekonomijom, kako bi se riješio problem odlaganja otpada i usmjerilo na njegovo ponovo korištenje. Posljednjih godina otpad taloga kave privlači veliku pažnju jer se stvara u velikim količinama svake godine i može uzrokovati ekološke probleme ako se ne zbrine pravilno. Kava je jedno od najpopularnijih pića koje se konzumira diljem svijeta. Stoga bi razvoj tehnologija za ponovnu upotrebu otpada taloga kave u funkcionalne svrhe pomogao pretvoriti ovu veliku količinu otpada u nove resurse. Ovo istraživanje ima za cilj iskoristiti otpada taloga kave kao punila, s minimalnim procesima pripreme, za pripremu kompozita s polilaktidom (PLA) kao matricom. Biorazgradivi PLA izvrstan je izbor kao matrica jer je održiva alternativa petrokemijskim proizvodima, može se pripraviti iz obnovljivih izvora energije te se lako dobiva mikrobiološkom fermentacijom. Svrha ovog istraživanja je pretvoriti otpad taloga kave u novi resurs kako bi se smanjila cijena PLA i na kraju smanjila opasnost za okoliš. U radu su pripravljeni kompoziti PLA/otpad taloga kave zamiješavanjem u Brabender gnjetilici i prešanjem na hidrauličkoj preši. Udio punila otpada taloga kave u uzorcima kompozita bio je 5, 10, 15 i 20 mas.%. Toplinska svojstva kompozita PLA/otpad taloga kave ispitana su diferencijalnom pretražnom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA). Ispitana je i veličina čestica te raspodjela veličina čestica metodom laserske difrakcije, te apsorpcija vode. Rezultati toplinskih svojstava pokazali su da otpad taloga kave nema utjecaja na fazne prijelaze PLA matrice, dok utječe na smanjenje toplinske stabilnosti. Ispitivanje apsorpcije vode pokazalo je da što je veći udio otpada taloga kave dolazi do veće apsorpcije vode kompozita PLA/otpad taloga kave zbog izraženog hidrofilnog karaktera punila.
Abstract (english) Due to the growing problem of environmental pollution and waste disposal in recent years, emphasis is being placed on the zero-waste concept. More and more industrial enterprises are replacing the concept of linear economy with circular economy to solve the problem of waste disposal and focus on waste reuse. In recent years, used coffee grounds have attracted a lot of attention because they are produced in large quantities every year and can cause environmental problems if not disposed of properly. Coffee is one of the most consumed beverages in the world. Therefore, developing technologies to reuse coffee grounds for functional purposes would help convert this large amount of waste into new resources. This research aims to use used coffee grounds as a filler with minimal preparation processes for the production of composite materials with polylactide (PLA) as a matrix. Biodegradable PLA is an excellent choice as a matrix because it is a sustainable alternative to petrochemical products, can be produced from renewable energy sources, and is easily obtained by microbial fermentation. The goal of this research is to convert used spent coffee grounds into a new resource to reduce the cost of PLA and ultimately reduce environmental risks. In this work, composites of PLA and spent coffee grounds were produced by mixing in a Brabender kneader and pressing in a hydraulic press. The mass fraction of spent coffee grounds in the composite was 5, 10, 15, and 20 wt. %. The thermal properties of the PLA/spent coffee grounds composites were tested using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). Particle size and particle size distribution were investigated using the laser diffraction method, as well as water absorption. The thermal property results showed that spent coffee grounds had no effect on the phase transitions of the PLA matrix, while it decreased the thermal stability. The water absorption test showed that the higher the percentage of spent coffee grounds, the higher the water absorption of the PLA/spent coffee grounds composite, which is due to the markedly hydrophilic character of the filler.
Keywords
kompoziti
polilaktid (PLA)
otpad taloga kave
Keywords (english)
composites
polylactide (PLA)
spent coffe grounds
Language croatian URN:NBN urn:nbn:hr:149:069309 Project Number: IP-2019-04-9661 Study programme Title: Applied Chemistry - Undergraduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2023-02-21 08:41:19
