Mark D. Soucek

Preparation and characterization of alkoxysilane functionalized isocyanurates

Alkoxysilane functionalized isocyanurates were prepared from hexamethylene diisocyanate (HDI) isocyanurate and 3-aminopropyltriethoxysilane. The reactants and functionalized isocyanurate were characterized by 1H, 13C and 29Si NMR, IR and electrospray ionization-mass spectrometry. Two-dimensional NMR was necessary to accurately assign the proton and carbon spectra for both the reactants and functionalized products. The composition of the HDI isocyanurate was a mixture of oligomers ranging from two to three HDI monomers. The functionalization reaction was performed neat, and as a function of dilution. As expected, substitution on the isocyanurate becomes more uniform with increasing solvent content.

Inorganic–organic hybrid coatings with mixed metal oxides

Abstract Ceramer coatings were developed using soybean oil as the organic phase with mixtures of titanium(IV) isopropoxide (TIP) and zirconium(IV) propoxide (ZRP) as the inorganic phase. TIP was also used in combination with zinc acetate dihydrate and zinc phosphate, with the zinc serving as an anticorrosive agent. The properties of the coatings were evaluated to determine whether a beneficial synergistic effect is obtained by using mixed metal oxides as the inorganic phase. Hardness, adhesion, flexibility, impact resistance, fracture toughness, tensile properties, and dynamic mechanical properties were investigated. Ultraviolet spectroscopy revealed that the zinc acetate dihydrate and the zinc phosphate react with the sol–gel precursor of the inorganic phase. Beneficial synergistic effects were observed in tensile modulus, fracture toughness, and the energy release rate at fracture for equal-weight-percent mixtures of TIP and ZRP.

Acid-catalyzed moisture-curing polyurea/polysiloxane ceramer coatings

The para-toluene sulfonic acid (p-TSA) was used to catalyze the moisture curing of an organic/inorganic hybrid coating system. The organic phase was based on the isocyanurate of 1,6-hexamethylene of diisocyanate (HDI). The inorganic phase was based on the prepolymerized oligomers of tetraethyl orthosilicate (TEOS). An alkoxysilane-functionalized HDI isocyanate was added into the coating formulation to aid in phase miscibility. The general coating and tensile properties were evaluated as a function of the acid catalyst concentration. In addition, the films were analyzed using differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). The results indicated that the acid catalyst enhanced the adhesive properties of the hybrid coatings. The addition of the acid catalyst increased the changed crosslink density of films and decreased the crystallinity of the organic phase.

Moisture-curing alkoxysilane-functionalized isocyanurate coatings

An amilnosilane functionalzed isocyanurate of 1,6-hexamethylene diisocyanate (HDI isocyanurate) was used to formulate coatings. The coatings were formulated using a mixture of the silane-functionalized isocyanurate and the unfunctionalized HDI isocyanurate. The general coating properties and tensile properties were evaluated as a function of alkoxysilane modified isocyanurate. In addition, the thermo-machanical and rheological properties of the films were also investigated. The moisture-curing process was investigated using FT-IR and NMR. The results indicates that alkoxysilane-functionalized isocyanurate dramatically enhances the adhesion and increases the crosslink density.

Synthesis of reactive diluents for cationic cycloaliphatic epoxide UV coatings

Abstract Reactive diluents for cationic cycloaliphatic epoxide UV coatings were synthesized using caprolactone polyols and tetraethyl orthosilicate (TEOS). The structures of the TEOS functionalized polyols were characterized using IR, 1 H-NMR, 29 Si-NMR, and ESI-FTMS spectroscopy. The resulting siloxane functionalized polyols were used to formulate cationic UV coatings with 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexane carboxylate (a cycloaliphatic diepoxide). The crosslinking reactions were monitored using IR and 29 Si-NMR spectroscopy. The cured films were evaluated in terms of tensile properties and glass transition temperature. The resultant coatings showed greater tensile modulus, lower elongation, and higher glass transition temperature. In addition, the siloxane functionalized polyols also effectively reduced the viscosity of the coatings formulations. Based on the curing behaviors and spectroscopic data, possible crosslinking reaction(s) were postulated.

Differential scanning calorimetry study of linseed oil cured with metal catalysts

Differential scanning calorimetry (DSC) has been used to study the autoxidative curing process of linseed oil catalyzed by conventional metal driers and two metal sol-gel precursors, Ti(Oi-Pr)2(acac)2 and Ti(Oi-Pr)4, at elevated temperatures. Linseed oil resins with a range of 0–5.0 wt.% metal sol-gel precursor and 0–9.0 wt.% zirconium dric have been investigated by both dynamic and isothermal methods. The onset, peak and end temperatures of the reaction exotherms were observed as a function of metal catalyst type and content. The Borchardt and Daniels kinetics method was used to quantify the heat of reaction of the dynamic DSC scans. The indention hardness of the resultant coatings in the DSC sample pans was measured as an indication of crosslink density. The inclusion of small quantities of metal catalyst (0–5.0 wt.% titanium alkoxide, 0–2.0 wt.% zirconium drier) caused the reaction exotherm to broaden and shift to lower temperatures. At higher metal catalyst content (>5.0 wt.% Ti(Oi-Pr)2(acac)2 or 5.0 wt.% Ti(Oi-Pr)4) the reaction exotherms became imperceptible. Overall, as the metal catalyst content was increased, the heat of reaction decreased while indention hardness increased. The effects of the two sol-gel precursors on the reaction exotherms were similar to the effects of conventional driers. Combinations of conventional driers were also studied.

Crosslinking of acrylic latex coatings with cycloaliphatic diepoxide

Abstract Acrylic thermosetting latexes were synthesized using methyl methacrylate (MMA) and butyl acrylate (BA) with methacrylic acid (MAA) or 2-hydroxyethyl methacrylate (HEMA). The MAA or HEMA was incorporated to provide the latexes with carboxyl or hydroxyl functionality, respectively. A cycloaliphatic diepoxide (3,4-epoxycyclohexyl methyl-3′,4′-epoxycyclohexane carboxylate) was used to crosslink with hydroxyl or carboxyl functional latexes. The coatings were crosslinked as a function of temperature, time, and the amount of the crosslinker. The crosslinking reactions were monitored using differential scanning calorimeter, IR spectroscopy, and dynamic mechanical thermal analysis. The coatings properties were evaluated in terms of water absorption, gel content, pencil hardness, and pull-off adhesion. The morphology of the latex coatings was studied using atomic force microscopy. The spectroscopic and rheological data showed that the cycloaliphatic diepoxide effectively crosslinked both the hydroxyl and carboxyl functional latexes. Carboxyl latex coatings were more reactive than hydroxyl latex coatings. The water resistance, solvent resistance, pencil hardness, and pull-off adhesion improved with the crosslinking temperature, time, and the amount of the crosslinker.

Linseed and sunflower oil alkyd ceramers

Abstract New inorganic/organic hybrid coatings were prepared, using linseed and sunflower oil based alkyds with sol–gel precursors. Three sol–gel precursors, titanium (IV) i -propoxide (TIP), titanium di- i -propoxide, diacetylacetonate (TIA), and zirconium (IV) n -propoxide (ZRP), were used in this study. The goal of this study was to investigate the affects of the type of alkyd on the overall properties of the alkyd ceramer coating. Various coatings properties such as hardness, impact resistance, adhesion, tensile properties and flexibility were evaluated as a function of alkyd type and sol–gel precursor content. Thermal and mechanical properties were also investigated as a function of sol–gel precursor and alkyd type. Alkyd ceramers high in linolenic acid content produced harder, tougher films while maintaining the same degree of flexibility as the high linoleic acid alkyds. At low sol–gel precursor content, the tensile properties of both the sunflower and linseed oil based alkyd ceramers initially decreased. As the sol–gel content was increased, the tensile properties increased as a function of sol–gel content.

Novel inorganic/organic hybrid materials based on blown soybean oil with sol-gel precursors

Abstract New ceramer coatings based on blown soybean oil with sol–gel precursors were prepared and evaluated as a function of the blowing process and sol–gel precursors content. Soybean oils were blown at three different rates in order to optimize the blowing process. Three sol–gel precursors, titanium (IV) i-propoxide, titanium (IV) di-i-propoxide bis-acetoacetonate, and zirconium n-propoxide were then used with the blown oil to investigate the effect of sol–gel precursors content on film properties. The gelation and film properties of ceramer coatings were dependent on chemical composition, which was a function of blowing time and blowing rate. Both tensile properties and general coatings properties (including adhesion, hardness, impact resistance, and flexibility) were investigated as a function of sol–gel precursor content. In general, higher sol–gel precursor content increased tensile strength and modulus, but decreased impact resistance.

Oxidizing alkyd ceramers

New inorganic/organic hybrid coatings known as ceramers were prepared using an oxidizing alkyd. Three sol-gel precursors, titanium(IV)-i-propoxide (TIP), titanium diisopropoxide bis(acetylacetonate) (TIA), and zirconium(IV)-n-propoxide (ZRP) were evaluated as a function of weight percent. The goal of this study was to formulate ceramer coatings which could be cured on a commercially viable time schedule. Overall, coating properties were found to be dependent on the type and amount of sol-gel precursor. The sol-gel precursor was also found to interact with the drier used to cure the alkyd.