Hydrophobic polyurethane powder clear coatings with lower curing temperature: Study on the synthesis of new blocked polyisocyanates

Czachor-Jadacka, Dominika; Pilch‐Pitera, Barbara; Byczyński, Łukasz; Kisiel, Maciej; Zioło, Aleksandra

doi:10.1016/j.porgcoat.2021.106402

Cited by 13 publications

(5 citation statements)

References 24 publications

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“…This migration is inhibited by chemical bonds formed between the cyclotriphosphazene hydroxyl groups and polyisocyanate during the coating cross-linking process. A similar process was observed in our earlier research on polyurethane powder coatings modified with polysiloxanes or fluoropolyols [51].…”

Section: Phosphorus Distribution In the Cured Coatingssupporting

confidence: 84%

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance

Pilch-Pitera,

Czachor-Jadacka,

Byczyński

et al. 2024

Materials

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Protection against fire and the corrosion of metals is necessary to ensure human safety. Most of the fire and corrosion inhibitors do not meet the ecological requirements. Therefore, effective and ecological methods of protecting metals are currently a challenge for researchers. In this work, the influence of hexakis(4-(hydroxymethyl)phenoxy)cyclotriphosphazene (HHPCP) on the characteristics of powder coatings was examined. The coatings’ properties were investigated by measuring the roughness, hardness, adhesion to the steel surface, cupping, gloss, scratch resistance, and water contact angle. The thermal stability was studied by furnace test and TGA analysis. The corrosion resistance test was carried out in a 3.5% NaCl solution. The distribution of phosphazene-derived segments in the coating was examined by GD-EOS analysis. Modified coatings show better corrosion and thermal resistance and can be used for the protection of the steel surface. Their better corrosion resistance is due to the electroactive properties of the phosphazene ring and its higher concentration at the coating surface, confirmed by GD-EOS analysis. The increase in thermal resistance is due to the effect of the formation of phosphoric metaphosphoric and polyphosphoric acids during the decomposition of HHCPC, which remain in the condensed char phase and play a crucial role in surface protection.

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Section: Phosphorus Distribution In the Cured Coatingssupporting

confidence: 84%

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance

Pilch-Pitera,

Czachor-Jadacka,

Byczyński

et al. 2024

Materials

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“…Being a byproduct of the biodiesel industry makes this biobased crosslinker a key component to improve the thermomechanical properties of the final polymer. Even though glycerin has been used previously as a crosslinker as well as a starter for polyol synthesis, [17][18][19][20] the authors have not found any study using the formulation proposed in this study.…”

Section: Introductionmentioning

confidence: 99%

Kinetic and chemorheological modeling of thermosetting polyurethanes obtained from an epoxidized soybean oil polyol crosslinked with glycerin

Armanasco

D’hers

Chiacchiarelli

2022

J of Applied Polymer Sci

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Thermosetting polyurethanes were obtained using an aromatic isocyanate and a hydrophobic polyol formulation obtained from epoxidized soybean oil (ESO) crosslinked with glycerin. A systematic DSC analysis of the effect of catalyst type, crosslinker concentration, isocyanate index and ESO crystallization on cure kinetics was conducted. The combination of a stannic catalyst at 0.2 wt% and glycerin at 20 wt% produced a cure kinetics governed by an autocatalytic heat flow where vitrification played a key role in the formation of chemical bonds. The evolution of T g as a function of conversion, which followed Di-Benedetto's predictions, supported the hypothesis that vitrification was a preponderant phenomenon during cure. Dynamic Mechanical Analysis (DMA) of a post-cured sample revealed a Tg centered at 220 C, whereas quasi-static flexural mechanical tests shown a flexural modulus of 2.14 GPa and a flexural strength of 99.4 MPa. Rheological experiments at isothermal conditions supported the hypothesis that vitrification played a key role in the evolution of apparent viscosity. A master model using Kim-Macosko equations was obtained for the proposed formulation. The results presented in this work will serve to further extend the use of biobased polymers applied in the polymer composite industry.

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“…The characteristic absorption peak of isocyanate was detected by FT‐IR spectroscopy, and the initial deblocking temperature of the sample was determined from the temperature corresponding to the appearance of the isocyanate band 12,13,27 . The mass loss and endothermic peak result from the release of the blocking agent and the change in heat flow on the breaking of the bond.…”

Section: Resultsmentioning

confidence: 99%

“…The characteristic absorption peak of isocyanate was detected by FT-IR spectroscopy, and the initial deblocking temperature of the sample was determined from the temperature corresponding to the appearance of the isocyanate band. 12,13,27 The mass loss and endothermic peak result from the release of the blocking agent and the change in heat flow on the breaking of the bond. Therefore, thermogravimetric analysis (TGA) and DSC can also be used to determine the deblocking temperatures of blocked isocyanates; however, the error in these calculations is large, and we stress that the determination of the deblocking temperature of the same blocked isocyanate is highly dependent on test method, heating rate, and other factors.…”

Section: Deblocking Reaction Analysismentioning

confidence: 99%

Influence of the melting point on the deblocking reaction of methyl ethyl ketoxime‐blocked aromatic polyisocyanates

Zhai

Meng

et al. 2022

J of Applied Polymer Sci

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Blocked polyisocyanates are used in single component (1 K) water‐based and powder coatings to simplify coating synthesis and reduce waste. However, the relationship between the melting point and deblocking behavior of blocked polyisocyanates is not clear. We aim to determine the influence of the melting temperature on the deblocking of methyl ethyl ketoxime (MEKO)‐blocked aromatic polyisocyanates. A toluene‐2,4‐diisocyanate trimer grafted with different mass ratios of methoxypolyethylene glycol (MPEG) is used to achieve compounds with different melting points and is blocked with MEKO. The deblocking behaviors of the polymers are investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, and thermogravimetric analysis. The results show that the deblocking temperature and average activation energy of the blocked polyisocyanates decrease with increase in melting point. Further, MEKO is more likely to be lost from blocked polyisocyanates having lower melting points. Furthermore, polyacrylic resins cured with blocked polyisocyanates having low melting points exhibit better properties than those having high melting points. The results reveal that the reduction in melting point induced by grafting with MPEG can significantly reduce the deblocking temperature of blocked polyisocyanates. The improvements in these properties may help achieve the low‐temperature crosslinking of blocked polyisocyanates for coating technologies.

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Hydrophobic polyurethane powder clear coatings with lower curing temperature: Study on the synthesis of new blocked polyisocyanates

Cited by 13 publications

References 24 publications

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene as an Environmentally Friendly Modifier for Polyurethane Powder Coatings with Increased Thermal Stability and Corrosion Resistance

Kinetic and chemorheological modeling of thermosetting polyurethanes obtained from an epoxidized soybean oil polyol crosslinked with glycerin

Influence of the melting point on the deblocking reaction of methyl ethyl ketoxime‐blocked aromatic polyisocyanates

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