Modifikacija hidrofobnosti površine dvokomponentnih polimernih mješavina za aditivnu proizvodnju mikroreaktora

doctoral thesis

• Title (english): Modification of surface hydrophobicity of two-component polymer blends for additive manufacturing of microreactors
• Author: Vedrana Lovinčić Milovanović
• Mentor: Domagoj Vrsaljko (mentor)
• Committee member: Krunoslav Žižek (predsjednik povjerenstva)
• Committee member: Igor Dejanović (član povjerenstva)
• Committee member: Goran Mihulja (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2020-05-29, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Chemical Engineering in Material Development
• Universal decimal classification (UDC): 66 - Chemical technology. Chemical and related industries

Abstract

Polilaktid (PLA) i akrilonitril/butadien/stiren (ABS) dva su najčešće korištena polimera za aditivnu proizvodnju rastaljenim filamentom. Aditivna je proizvodnja široj javnosti poznatija pod nazivom tehnologija 3D-ispisa ili 3D-printanje. S ciljem razvoja materijala za izradu mikroreaktora aditivnom proizvodnjom pripremljene su polimerne mješavine PLA i ABS s polietilenom velike gustoće (PE-HD) i polietilenom niske gustoće (PE-LD) u različitim omjerima i pri različitim uvjetima pripreme. Polimernim su mješavinama ispitana mehanička i toplinska svojstva te je određena morfologija površine. Potom je ispitana mogućnost povećanja hidrofobnosti površine polimernih mješavina tehnikom selektivnoga jetkanja induktivno spregnutom plazmom (engl. Inductively Coupled Plasma, ICP) i obradom površine fluorougljicima. Dobiveni su rezultati pokazali da temperatura pripreme (160 °C vs. 180 °C) i način miješanja (ekstruder vs. gnjetilica) polimerne mješavine nemaju značajnoga utjecaja na mehanička svojstva polimernih mješavina. Najveći utjecaj na mehanička svojstva polimernih PE mješavina ima raspodjela veličine dispergirane faze u matrici. Bolja su mehanička svojstva pokazale polimerne mješavine s užim rasponom veličine domena i jednolikom raspodjelom domene u matrici, konkretno uzorci s PE-HD-om. Ispitivanjem mogućnosti povećanja hidrofobnosti površine pokazalo se da je površinu polimernih mješavina s PLA-om moguće značajno modificirati ICP jetkanjem i prevlačenjem fluorougljicima, dok isto nije moguće za polimerne mješavine s ABS-om pri ispitanim uvjetima. Obradom površine PLA/PE-HD 90/10 postignut je kontaktni kut vode za 36° veći od kontaktnoga kuta koji je izmjeren na neobrađenoj površini i iznosi 121,6°. Površine koje pokazuju visoke kontaktne kutove vode (> 120°) imaju „strukturu otoka” na površini. Uzorcima s višim „otocima” izmjereni su i viši kontaktni kutovi, čime je potvrđeno da hidrofobnost površine ovisi i o hrapavosti, tj. visini „otoka”. Isto tako, pokazalo se kako duže vrijeme jetkanja ima značajan utjecaj na vrijednosti kontaktnoga kuta, kao i na površinsku morfologiju polimernih mješavina s PLA-om, dok duže vrijeme prevlačenja fluorougljicima nema značajnoga utjecaja na karakteristike površine. Za polimernu mješavinu PLA/PE-HD 90/10 pokazano je da se može izraditi filament i izraditi mikroreaktor tehnologijom 3D-ispisa.

Abstract (english)

Polylactide (PLA) and acrylonitrile/butadiene/styrene (ABS) are the most commonly used polymers for the additive manufacturing using fused filament fabrication. Additive manufacturing is commonly known as „3D printing“. In order to develop new materials for 3D printing of microreactors, these two polymers were blended with high-density polyethylene (PE-HD) and low-density polyethylene (PE-LD) under different process conditions in several ratios. Mechanical and thermal properties, as well as morphology of polymer blends are determined. In order to investigate the possibilities of designing hydrophobicity of polymer blends to gain more control over fluid flow inside microchannels of 3D printed microreactors polymer blends surfaces were etched using inductively coupled plasma (ICP) and coated by fluorocarbon-based material (CFx) plasma deposition treatment in the second step. The results obtained showed that the preparation temperature (160 °C vs. 180 °C) or the mixing equipment (extruder vs. kneader) of the polymer blends had no significant effects on the mechanical properties of the polymer blends. The greatest influence on the mechanical properties of polymer blends has the size distribution of the dispersed phase in the matrix. Better mechanical properties showed samples with a narrow size distribution of the dispersed phase domain that are uniformly distributed within the polymer matrix. Such specific morphology showed samples with PE-HD. Regarding the hydrophobicity, it has been shown that the surface morphology of PLA polymer blends can be highly modified by etching and CFx coating, while it was not possible for ABS polymer blends under the conducted treatment conditions. The treated surface of PLA/PE-HD 90/10 showed contact angle of 121.6° which is up to 36° higher than the contact angle measured on the untreated surface. Surfaces achieving high contact angles (> 120°) have “island like” surface morphology. Samples with higher "islands" showed higher contact angles, that confirmed that the hydrophobicity also depends on the height of the "islands". Furthermore, it has been revealed that the longer time of etching has significant impact on the contact angle values as well as surface morphology of the PLA polymer blends, while the longer time of CFx coating has no significant impact on the surface characteristics. Furthermore, it has been shown that filament for 3D printing can be made of PLA/PE-HD 90/10 polymer blend as well as 3D printed microreactor.

• Keywords: 3D-ispis; ABS; aditivna proizvodnja; hidrofobnost; jetkanje; mikroreaktor; PLA
• Keywords (english): 3D printing; ABS; additive manufacturing; hydrophobicity; etching; microreactor; PLA
• Language: croatian
• URN:NBN: urn:nbn:hr:149:744242
• Promotion: 2020
• Project: Number: UIP-2014-09-3154; Title: Razvoj materijala za 3D tiskanje mikroreaktora; Title: Development of materials for 3D printing of microreactors; Acronym: 3Dmicroreactors; Leader: Domagoj Vrsaljko; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: UIP
• Study programme: Title: Chemical Engineering and Applied Chemistry - Doctoral course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo (doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo)
• Type of resource: Text
• Extent: 109 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2021-06-30
• Created on: 2023-06-07 14:07:06