Istraživanje procesa starenja plastičnih otpadnih materijala pri atmosferskim uvjetima

undergraduate thesis

• Title (english): Study of the aging process of plastic waste materials under atmospheric conditions
• Author: Luka Očić
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Elvira Vidović (član povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-09-01, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Na uzorcima poli(etilen tereftalata) (PET), u obliku komercijalno dostupnih boca i folija, provođeno je toplinsko ubrzano starenje, koje simulira atmosfersko toplinsko starenje. Pratilo se starenje plastičnog otpada kako bi se stekao uvid u degradaciju plastike u okolišu, koja s vremenom prelazi u mikroplastiku (MP) te ocijenio njihov utjecaj na okoliš. Uzorci folija debljine stjenke 0,75 mm i boca debljine stjenke 0,25 mm toplinski su stareni u periodu od 14, 28 te 42 dana, a dnevni ciklus starenja bio je: 16h na 70 °C, 2h na -18 °C i 6 h na 70 °C uz povećani sadržaj vlage. Nakon starenja uzorci su karakterizirani FTIR spektrometrom gdje se proučavalo odaziv karakterističnih veza funkcionalnih skupina unutar molekula PETa, posebno karbonilne skupine te je izračunat karbonilni indeks (C.I.), čija se promjena javlja kao posljedica razgradnje polimerne molekule. Također, uzorci su karakteriziran DCS analizom gdje je praćena promjene temperature staklastog prijelaza (Tg) te promjena stupnja kristalnosti s vremenom starenja (X). Rezultati dobiveni u ovom radu ukazuju da je utjecaj starenja vrlo mali u kratkim vremenskim periodima zbog izuzetne stabilnosti PET-a pri atmosferskim uvjetima. No, zabilježene su određene promjene u strukturi molekule PETa, koje ukazuju na razgradnju molekula, njihovo kidanje i nastajanje manjih molekula polimera. Tako je iz rezultata vidljivo da je došlo do pada kristalnosti, a C.I. indeks je pao za 33% nakon 42 dana toplinskog starenja.

Abstract (english)

Commercially available poly(ethylene terephthalate) (PET) in the shape of bottles and foils has been thermally aged, which simulates atmospheric thermal aging. The aging of plastic waste has been studied in order to gain insight into the degradation of plastics in the environment, which over time turns into microplastics (MP) and to assess their impact on the environment. The samples of PET foil was 0.75 mm thick and PET bottles 0.25 mm thick have been thermally aged for a period of 14, 28 and 42 days, with a daily cycle that was as follow: 16h at 70°C, 2h at -18°C and 6h at 70°C with an increased amount of moisture. After aging the samples have been analysed with FTIR spectrometer where the characteristic signals of functional groups within the molecule of PET have been recorded, of which the most important was the carbonyl group. From that data the Carbonyl index (C.I.) was calculated, which change indicate the degradation of the polymer molecules. Also, the samples have been analysed using DSC method where the glass transition temperature (Tg) and the degree of crystallinity (X) over time have been determined. The results of this paper indicate that the effect of aging is low due to the short periods of aging time because PET polymer exhibited exceptional stability under atmospheric conditions. Although, some changes in the structure of PET molecules have been noted, which indicate the degradation of the macromolecules and the formation of molecules of lower molecular masses. From the results a notable decrease in the crystallinity is visible and the C.I. has decreased by 33% after 42 days of thermal aging.

• Keywords: starenje plastike; plastični otpad; poli(etilen tereftalat); atmosfersko starenje
• Keywords (english): aging of plastic; plastic waste; poly(ethylene terephthalate); weathering
• Language: croatian
• URN:NBN: urn:nbn:hr:149:577396
• Project: Number: IP-2020-02-6033; Title: Mikroplastika u vodi; sudbina, ponašanje i uklanjanje; Title: Microplastics in water; fate and behavior and removal; Acronym: ReMiCRO; Leader: Ana Lončarić Božić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Applied Chemistry - Undergraduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Advanced materials and technologies; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) primijenjene kemije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-04-12 11:10:44