Priprema i karakterizacija mješavina poli(mliječne kiseline) s novim biorazgradljivim polihidroksialkanoatom srednje duljine lanca

master's thesis

• Title (english): Preparation and characterization of blends of polylactic acid with a new biodegradable medium-chain-length polyhydroxyalkanoate
• Author: Dora Milički
• Mentor: Vesna Ocelić Bulatović (mentor)
• Committee member: Vesna Ocelić Bulatović (predsjednik povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Committee member: Dajana Kučić Grgić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2024-09-24, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Interdisciplinary Technical Sciences

Abstract

Gotovo polovica globalne proizvodnje plastike primjenjuje se u svrhu proizvodnje ambalaže za pakiranje hrane. Korištenje polimera na bazi fosilnih goriva koji nisu biorazgradljivi rezultira velikim ekološkim posljedicama. Glavni nedostatak sintetskih polimera jest nagomilavanje plastičnog otpada u okolišu što rezultira velikim ekološkim posljedicama. Iako su poznate brojne metode za gospodarenje otpadom, polimeri na bazi fosilnih goriva teško podliježu biorazgradnji ili recikliranju. Biorazgradljivi polimeri poput poli(mliječne kiseline) (PLA) i
poli(3-hidroksibutirat-ko-3-hidroksivalerata) (PHBV) pokazali su se kao moguća alternativa za takve sintetske i teško razgradljive polimere. Obzirom na slabija funkcionalna svojstva pojedinih polimera poput PLA i PHBV, daje se naglasak polimernim mješavinama s ciljem razvoja poboljšanih svojstava čistih polimera. U ovom radu ispitana su svojstva polimernih mješavina na bazi PLA i PHBV s udjelom PLA od 65, 70, 75, 80 i 85 mas. % te čistih uzoraka. Pretražnom elektronskom mikroskopijom (SEM) utvrđena je homogena struktura polimernih mješavina kao rezultat međufazne adhezije između PLA i PHBV. Promjene u kemijskoj strukturi i informacije o kemijskom sastavu dobivene su FTIR-ATR tehnikom te je utvrđeno međudjelovanje između PLA i PHBV u mješavinama obzirom na pomake apsorpcijskih vrpci. Mjerenjem kontaktnog kuta s vodom potvrđena je hidrofobnost površina svih uzoraka. Toplinska svojstva ispitana su diferencijalnom pretražnom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA). DSC analizom utvrđena je djelomična mješljivost polimernih mješavina te da PHBV pogoduje kristalizaciji PLA. TGA analizom određena je toplinska razgradnja polimernih mješavina koja se odvija u dva stupnja. Također, povećanjem udjela PLA (od 80 mas. % PLA) toplinska stabilnost PLA/PHBV polimernih mješavina se povećava. Vrijednosti propusnosti vodene pare uzoraka polimernih mješavina nalaze se između vrijednosti čiste PLA i PHBV te porastom udjela PHBV (od 25 mas. % PHBV) poboljšavaju se barijerna svojstva PLA/PHBV polimernih mješavina.

Abstract (english)

Almost half of the global production of plastic is used to produce food packaging. The use of fossil fuel-based polymers that are not biodegradable results in major environmental consequences. The main disadvantage of synthetic polymers is the accumulation of plastic waste in the environment, which results in major environmental consequences. Although numerous methods are known for waste management, polymers based on fossil fuels are difficult to biodegrade or recycle. Biodegradable polymers such as poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) have proven to be a possible alternative for such synthetic and difficult-to-degrade polymers. Considering the weaker functional properties of certain polymers such as PLA and PHBV, emphasis is given to polymer blends to develop improved properties of pure polymers. In this work, the properties of polymer blends based on PLA and PHBV with a PLA content of 65, 70, 75, 80, and 85 wt. % were investigated. Scanning electron microscopy (SEM) revealed a homogeneous structure of the polymer blends due to interfacial adhesion between PLA and PHBV. Changes in the chemical structure and information on the chemical composition were investigated by the FTIR-ATR technique, and the interaction between PLA and PHBV in the blends was determined by the shifts of the absorption bands. By measuring the contact angle with water, the hydrophobicity of the surface of all samples was confirmed. Thermal properties were tested by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC analysis revealed partial miscibility of polymer blends and that PHBV favors the crystallization of PLA. TGA analysis determined the thermal decomposition of polymer blends, which takes place in two stages. Also, by increasing the proportion of PLA (from 80 wt. % PLA), the thermal stability of PLA/PHBV polymer blends increases. The values of water vapor permeability of polymer blend samples are between the values of pure PLA and PHBV, and increasing the proportion of PHBV (from 25 wt. % PHBV) improves the barrier properties of PLA/PHBV polymer blends.

• Keywords: PLA; PHBV; pakiranje hrane; polimerne mješavine
• Keywords (english): PLA; PHBV; food packaging; polymer blends
• Language: croatian
• URN:NBN: urn:nbn:hr:149:423981
• Project: Number: NPOO.C3.2.R3-I1.04.0059; Title: Proizvodnja i razvoj kompostabilne ambalaže iz otpadne biomase za pakiranje industrijski prerađenih prehrambenih proizvoda; Title: Production and development of compostable packaging from waste biomass for the packaging of industrially processed food products; Leader: Dajana Kučić Grgić; Jurisdiction: Croatia; Funder: Ministarstvo znanosti, obrazovanja i mladih Republike Hrvatske
• Study programme: Title: Applied Chemistry - Graduate study; specializations in: Environmental chemistry and green technologies, Advanced materials and technologies, Applied organic chemistry; Course: Applied organic chemistry; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra primijenjene kemije (sveučilišni/a magistar/magistra primijenjene kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-11-06 13:01:31