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Title:Vpliv sušilcev na kakovost premaznega filma v alkidnih premazih z visoko vsebnostjo suhe snovi
Authors:ID Pirš, Barbara (Author)
ID Venturini, Peter (Mentor) More about this mentor... New window
Files:.pdf DOK_Pirs_Barbara_2015.pdf (3,10 MB)
MD5: C8B06A1B976A1123B7C3F4EF62A5BA3A
 
Language:Slovenian
Work type:Doctoral dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Zaradi specifične kemijske strukture novih alkidnih veziv z visoko vsebnostjo suhe snovi (SS) in posledično spremenjenih aplikativnih lastnosti je zelo pomembna naloga določitev optimalne kombinacije in koncentracije sušilcev v premazu. Ob upoštevanju napovedi o omejitvi uporabe kobaltovih (Co) sušilcev v dekorativnih premazih smo primerjalno preučevali vpliv površinskih sušilcev: Co sušilca (Co etilheksanoat) in alternativnega železovega sušilca (Fe bispidon) posamezno in nato še v kombinaciji z globinskimi sušilci na osnovi stroncija (Sr karboksilat), cirkonija (Zr etilheksanojska kislina) in aluminija (Al organski kompleks) na proces avtooksidacije kot del utrjevanja alkidnih premazov z visoko vsebnostjo SS. Z infrardečo spektroskopijo s Fourierjevo transformacijo (FT-IR) smo analizirali mehanizem in kinetiko avtooksidacije. Preučevali smo čas sušenja in fizikalne lastnosti, kot so: reološko obnašanje, trdota, sijaj/meglica in barvne spremembe premazov. Z elektrokemijsko impedančno spektroskopijo (EIS) smo po izpostavi v vlažni komori ovrednotili kvaliteto utrjenega premaznega filma. Ugotovili smo, da proces avtooksidacije poteka po enakem mehanizmu v primeru Co in Fe sušilca, vendar pa je kinetika procesa različna. Potrdili smo, da Co sušilec izraziteje pospešuje proces avtooksidacije na površini premaza tudi v primeru alkidnih premazov z visoko vsebnostjo SS. Obratno Fe sušilec katalizira proces avtooksidacije počasneje vendar enakomerneje skozi celotno globino premaza. Dodatek inhibitorja nastanka kožice metiletil ketoksima (MEKO) vpliva na kinetiko avtooksidacije le pri kombinaciji s Fe sušilcem. Raziskava je v nadaljevanju pokazala, da dodatek globinskih sušilcev pomembno vpliva na začetek in hitrost avtooksidacijskega procesa. Z dodatkom višjih koncentracij globinskih sušilcev so bili končni časi sušenja krajši in vrednosti trdot premazov višje. Ostale fizikalne lastnosti so bile v primeru uporabe različnih kombinacij sušilcev primerljive. Rezultati EIS utrjenih premazov so potrdili različno delovanje Fe in Co sušilca. Z dodatkom nižjih koncentracij globinskih sušilcev so rezultati pokazali najnižjo Warburgovo difuzijo ionov skozi utrjeni premaz. Višje dodane koncentracije globinskih sušilcev v premaz pa so v večini primerov vplivale na višjo Warburgovo difuzivnost ionov in manjšo upornost por. Način delovanja Fe sušilca zahteva drugačen pristop pri optimizaciji procesa utrjevanja kot pri Co sušilcu, vendar pa je z uporabo Fe sušilca kot alternativo Co sušilcu mogoče doseči tako ustrezne aplikativne lastnosti sušenja kot tudi fizikalne lastnosti utrjenih filmov alkidnih premazov z visoko vsebnostjo SS.
Keywords:alkidni premazi, Co, Fe, sušilci, FT-IR, EIS
Place of publishing:Maribor
Publisher:[B. Pirš]
Year of publishing:2015
PID:20.500.12556/DKUM-55463 New window
UDC:667.613:678.674(043.3)
COBISS.SI-ID:19214870 New window
NUK URN:URN:SI:UM:DK:YLW7MVF6
Publication date in DKUM:14.12.2015
Views:1957
Downloads:65
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FKKT
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Secondary language

Language:English
Title:Influence of driers on the quality of the coating film in high solid alkyd coatings
Abstract:Due to specific chemical structure of new high solid (HS) alkyd resins and consequently changed applicative properties the optimal combination and concentration of driers has been an important subject of research. Considering the declaired limited use of cobalt (Co) driers in decorative coatings we performed a comparative study of surface Co drier (Co ethylhexanoate) and alternative iron drier (Fe bispidon) in combination with through driers: strontium- (Sr carboxylate), zirconium- (Zr ethylhexanoic acid) and aluminum-based (Al organic complex) driers on curing process of HS alkyd coating. Mechanism and the kinetics of autoxidation were analysed by FT-IR spectroscopy. Further, drying time and physical properties such as rheological behaviour, film hardness, haze/gloss and color change were investigated. The quality of cured HS alkyd coating films after exposure in the humidity chamber was evaluated by electrochemical impedance spectroscopy (EIS). The autoxidation mechanism of HS alkyd coatings is similar for Co and Fe driers. However, they influence on kinetic parameters of autooxidation process differently. It was confirmed that Co drier also has higher catalytic activity effect on the surface of HS alkyd coatings. On the other hand, Fe drier catalyzes autooxidation process slowly but more homogeneously along the depth of a coating film. Antiskinning agent methyl ethyl ketoxime (MEKO) influences on the kinetics of autooxidation only in combination with Fe drier. Further investigation has shown that the addition of through driers has significant influence on activation and speed of autooxidation process. The addition of higher concentrations of through driers resulted in shorter final drying times and higher film hardnesses of cured HS alkyd coatings. Other physical properties were comparable in case of different combination of used driers. EIS analysis confirmed different influences of Co and Fe driers on the quality of cured coating films. The addition of lower concentrations of through driers in most cases resulted in the lowest values of Warburg diffusion and lower pore resistance through the coating film. Different behavior of Fe drier compared to Co drier requires a different optimisation approach of surface/through driers in HS alkyd coatings to achieve the defined applicative curing parameters. Nevertheless, Fe drier can be used as an alternative to Co drier for curing of HS alkyd coatings in decorative application.
Keywords:HS alkyd coatings, Co, Fe, driers, FT-IR, EIS


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