Development of polyaspartic coating with improved adhesion on metallic surfaces by using nanosilica

doctoral thesis

• Title (croatian): Razvoj poliaspartatnog premaza s poboljšanom prionjivošću uporabom nanočestica silicijeva dioksida
• Author: Arezoo Assarian
• Mentor: Sanja Martinez (mentor)
• Committee member: Mirela Leskovac (predsjednik povjerenstva)
• Committee member: Emi Govorčin-Bajsić (član povjerenstva)
• Committee member: Vesna Alar (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2019-03-20, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Basic Technical Sciences; Materials
• Universal decimal classification (UDC): 620 - Materials testing. Power stations. Economics of energy ; 54 - Chemistry. Crystallography. Mineralogy

Abstract

The aim of this thesis was to investigate and develop polyaspartic coatings with nanosilica fillers modified with amino groups (NH2-) in order to enhance adhesion of coating on metallic surfaces and increase the productivity of the protective coating. The idea was to develop polyaspartic coating formulations for applying directly to metal surfaces (DTM). For this purpose, seven samples of polyaspartic coatings with different amounts of nanosilica filler of 20–30 nm in size were prepared. The coatings were applied on 2 mm thick low carbon steel panels prepared according to surface preparation standard Sa 2.5. The samples were characterized by mechanical testing with respect to hardness, adhesion, bending and impact resistance. The results showed that only 2% of the nanosilica per total mass of formulation improved adhesion of the coating to the surface of the substrate and that it was possible to apply the coating directly to the metal surface. Also, nanosilica filler changed the functionality of other particles or fillers, increased hydrophobic and oleophobic coating characteristics, altered rheology and thixotropy properties of coatings. After finalizing the formulation, degradation of coatings was analyzed by the electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) methods as well as by exposure of applied coatings to salty atmosphere in a salt spray chamber. No agglomeration and excellent compatibility of nanoparticles with other components in the formulation was observed. The main advantages of the modified polyaspartic coating were fast curing, fast drying time, excellent mechanical and chemical resistance and high film build which made it possible to reduce the number of coats in a coating system. The polyaspartic coating system with improved coating adhesion increased the durability of coating system and reduced volatile organic compounds (VOC) emissions and overall cost of the coating application process.

Abstract (croatian)

Cilj ove disertacije bio je istražiti i razviti poliaspartatne premaze s punilima na osnovi nanočestica silicijeva dioksida modificiranih amino-skupinama (NH2-) kako bi se poboljšala adhezija premaza na metalnim površinama i povećala produktivnost zaštitnog premaza. Ideja je bila razviti formulacije poliaspartatnih premaza za izravno nanošenje na metalne površine (DTM, engl. directly to metal). S tom je svrhom pripremljeno sedam uzoraka poliaspartatnog premaza s različitim udjelima nanočestica SiO2 dimenzija od 20 do 30 nm kao punila. Premazi su naneseni na ploče od niskougljičnog čelika debljine 2 mm uz pripremu površine prema standardu Sa 2.5. Uzorci su karakterizirani mehaničkim testovima s obzirom na tvrdoću, adheziju, savijanje i otpornost na udar. Rezultati su pokazali da samo 2 % nanočestica SiO2 po ukupnoj masi formulacije poboljšava adheziju premaza na površinu supstrata i da je moguće nanošenje premaza izravno na metalnu površinu. Također, nanočestice SiO2 mijenjaju funkcionalnost ostalih čestica ili punila, povećavaju hidrofobna i oleofobna svojstva premaza, mijenjaju njena reološka i tiksotropna svojstva. Nakon finaliziranja formulacije, degradacija premaza analizirala se metodama elektrokemijske impedancijske spektroskopije (EIS), pretražne (engl. scanning) elektronske mikroskopije (SEM) i infracrvene (engl. infrared) spektroskopije s Fourierovom transformacijom signala (FTIR), kao i izlaganjem primijenjenih premaza atmosferi u slanoj komori. Uočeno je da nema aglomeracije nanočestica te je utvrđena njihova izvrsna kompatibilnost s ostalim komponentama u formulaciji. Glavne prednosti modificiranog poliaspartatnog premaza bile su brzo očvršćivanje, brzo sušenje, izvrsna mehanička i kemijska otpornost i velika debljina mokroga premaza što omogućava smanjenje broja premaza u zaštitnom sustavu. Sustav poliaspartatnog premaza s poboljšanim prianjanjem povećava trajnost zaštitnog premaza i snižava emisiju hlapivih organskih spojeva i ukupni trošak procesa nanošenja premaza.

• Keywords: polyaspartic coatings; nanosilica fillers; adhesion; corrosion; protective coatings
• Keywords (croatian): poliaspartatni premazi; čestoce nanopunila; adhezija; korozija; zaštitni premazi
• Language: english
• URN:NBN: urn:nbn:hr:149:708231
• Promotion: 2019
• Study programme: Title: Engineering Chemistry - Doctoral Course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-03-05 09:33:30