Utjecaj višestrukog ekstrudiranja na kristalnu strukturu polipropilena

undergraduate thesis

• Title (english): The influence of multiple extrusion on the crystal structure of polypropylene
• Author: Dorotea Buhanec
• Mentor: Zlata Hrnjak-Murgić (mentor)
• Committee member: Zlata Hrnjak-Murgić (predsjednik povjerenstva)
• Committee member: Zvonimir Katančić (član povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2023-09-12, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Plastični se otpad radi povećanja proizvodnje i potrebe za plastikom sve češće može pronaći u okolišu. Njegovom degradacijom dolazi i do formiranja mikroplastike (MP), plastičnih fragmenata manjih od pet milimetara. Ona se lako prenosi kroz prirodu putem vjetra i voda, ali i kroz hranidbeni lanac pa tako predstavlja opasnost za neživi dio okoliša, floru, faunu te, naposlijetku, ljude. Cilj ovog rada bio je proučiti utjecaj višestrukog ekstrudiranja na uzroke polipropilena, termoplastičnog polimernog materijala. Mehaničko recikliranje polipropilena provedeno je na dvopužnom laboratorijskom ekstruderu, a granule su ekstrudirane pri temperaturnom profilu ekstrudera T = 170/190/190/195/200/200 °C pri brzini vrtnje pužnog vijka od 50 rpm u četiri ciklusa. Uzorci dobiveni ekstrudiranjem karakterizirani su infracrvenom spektroskopijom te rentgenskom difrakcijom (XRD). Infracrvena spektroskopija (FTIR) daje informacije o razgradnji uzorka, odnosno pojavi i/ili nestanku karakterističnih funkcionalnih skupina molekule polipropilena, a rentgenskom difrakcijom se utvrđuje strukturna uređenost kristala (homogenost, kristalnost). Višestrukim recikliranjem uzoraka polipropilena dolazi do pojave novih degradacijskih skupina koje sadrže kisik, a s povećanjem broja ciklusa ekstrudiranja one se rekombiniraju i/ili nestaju. Također, s povećanjem broja ciklusa ekstrudiranja, smanjuje se koncentracija degradacijskih skupina i kristalnost uzoraka, koji su u procesu ostali homogeni.

Abstract (english)

Plastic waste is increasingly found in the environment due to the growing production and demand for plastics. Its degradation leads to the formation of microplastics (MPs), plastic fragments smaller than five millimeters. Microplastics are easily transported through nature via wind and water, and they can also enter the food chain, posing a threat to the non-living environment, flora, fauna, and ultimately, humans. The aim of this study was to investigate the impact of multiple extrusion processes on the properties of polypropylene, a thermoplastic polymer material. Mechanical recycling of polypropylene was carried out using a twin-screw laboratory extruder, and the pellets were extruded at an extruder temperature profile of T = 170/190/190/195/200/200 °C with a screw rotation speed of 50 rpm in four cycles. Samples obtained through extrusion were characterized using infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Infrared spectroscopy provided information about the degradation of the samples, including the appearance and/or disappearance of characteristic functional groups in the polypropylene molecule. X-ray diffraction was used to determine the structural and the fraction of crystallinity (homogeneity, crystallinity). Multiple recycling cycles of polypropylene samples resulted in the emergence of new oxygen-containing degradation groups, which combined and/or disappeared with an increasing number of extrusion cycles. Additionally, as the number of extrusion cycles increased, the concentration of degradation groups and the crystallinity of the samples that remained homogeneous during the process decreased.

• Keywords: plastika; mikroplastika; polipropilen; ekstrudiranje; degradacija; kristalnost
• Keywords (english): plastic; microplastics; polypropylene; extrusion; degradation; crystallinity
• Language: croatian
• URN:NBN: urn:nbn:hr:149:322509
• 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: 2023-09-14 11:10:18