Effect of Molecular Weight of Poly(tetramethylene glycol) on Waterborne Polyurethane Dispersion Coating Gloss

Bhattarai, Saurabha; Lee, Sung‐Il; Lee, Dai‐Soo; Lee, Youn‐Sik

doi:10.1002/bkcs.11864

Cited by 9 publications

(7 citation statements)

References 12 publications

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“…Regarding the effect of the molecular weight of the polyol, Bhattari et al [ 16 ] prepared WBPU from polytetramethylene glycols (PTMGs) of different molecular weights and reported that the average size of the particles increased from 860 nm to 1355 nm for PTMGs of molecular weights of 1000 and 2000 Da, respectively. Thus, other conditions being equal, the increase in the length of the chain diol led to the increase in the average particle size of the WBPU.…”

Section: Resultsmentioning

confidence: 99%

“…Generally, large particles are used when rapid drying is needed, while small particles lead to longer drying times but allow the penetration of the PU in the substrate, which could be essential in some applications [ 15 ]. The structural molecular characteristics of the polyol, its functionality and molecular weight, the nature, characteristics, and concentration of the internal emulsifier, and the ratio of isocyanate to hydroxyl groups are factors that affect the properties of the dispersions and also of the final films [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

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Hybrid Films from Blends of Castor Oil and Polycaprolactone Waterborne Polyurethanes

2022

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Waterborne polyurethanes (WBPUs) with relatively high biobased content (up to 43.7%) were synthesized, aiming at their use as coatings for metals and woods. The study was performed on self-standing films obtained from anionic polyurethane water dispersions (PUDs). The initially targeted PUD was prepared from castor oil (CO), while tartaric acid (TA), a byproduct of wine production, was utilized as the internal anionic emulsifier. Although the films were cohesive and transparent, they were fragile, and thus blending the CO-TA PUD with other WBPUs was the chosen strategy to obtain films with improved handling characteristics. Two different WBPUs based on polycaprolactone diol (PCL), a biodegradable macrodiol, were prepared with dimethylolpropionic acid (DMPA) and tartaric acid (TA) as synthetic and biobased internal emulsifiers, respectively. The use of blends with PCL-TA and PCL-DMPA allowed for tailoring the moduli of the samples and also varying their transparency and haze. The characterization of the neat and hybrid films was performed by colorimetry, FTIR-ATR, XRD, DMA, TGA, solubility and swelling in toluene, and water contact angle. In general, the addition of PCL-based films increases haze; reduces the storage modulus, G’, which at room temperature can vary in the range of 100 to 350 MPa; and reduces thermal degradation at high temperatures. The results are related to the high gel content of the CO-TA film (93.5 wt.%), which contributes to the cohesion of the blend films and to the crystallization of the PCL segments in the samples. The highest crystallinity values corresponded to the neat PCL-based films (32.3% and 26.9%, for PCL-DMPA and PCL-TA, respectively). The strategy of mixing dispersions is simpler than preparing a new synthesis for each new requirement and opens possibilities for new alternatives in the future.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hybrid Films from Blends of Castor Oil and Polycaprolactone Waterborne Polyurethanes

2022

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“…Due to the incompatibility 13 of the matting agents with organic resins and precipitation problems in the coating layer, the matting agents may be difficult to disperse, reducing the mechanical properties of the cured coating film. 14 As for the self-matting resin, it is a chemical extinction method without any matting agents, and the rough surface is generated by the resin itself. 15 The objective of this strategy is to obtain large polymer particles by adjusting the weight ratio of hard/soft monomers, 16 and introducing hydrophilic units.…”

Section: Introductionmentioning

confidence: 99%

UV-curable self-matting waterborne polyurethane acrylate coatingviaself-wrinkled surface during curing in open-air

Zhang

2022

RSC Adv.

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“…As a new type of low-gloss material, self-matting waterborne polyurethanes usually have wider particle distribution, where large particles can play a role similar to matting agents, and small particles will impart better adhesion to the coating film [12][13][14][15]. Since no matting agent was contained in the dispersion, the film performance can be greatly improved, especially in the anti-scratch property.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Environmentally-Friendly Self-Matting Waterborne Polyurethane Coatings

et al. 2020

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A series of self-matting waterborne polyurethanes (WPUs) were successfully prepared by introducing hydrophilic units into both soft and hard segments. By employing a polycaprolactone polyol containing carboxylate groups within the polymer chains to provide hydrophilicity directly, the matting performance of WPU films was greatly improved. The chemical structures of the WPU resins were confirmed by FTIR spectroscopy, and the morphology of WPU films was observed by SEM. The parameters of WPU preparation were investigated in detail. It was found that the surface gloss of WPU films as well as the particle sizes of WPU dispersions were closely associated with the content of hydrophilic units. As the content of carboxylates or sulfonates increased, the particle sizes of WPU decreased, while the gloss increased gradually. When the particle sizes of dispersions were greater than 3 μm, the gloss of WPU films coated on a leather surface was lower than 1. The results of TG showed that, the initial decomposition temperatures of WPU films were higher than 280 °C, which indicated these films also had good thermal stability. The prepared self-matting WPU coatings would have potential application prospects in the field of leather finishing.

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Effect of Molecular Weight of Poly(tetramethylene glycol) on Waterborne Polyurethane Dispersion Coating Gloss

Abstract: FE‐SEM images of different WPU coating surfaces with different gloss values at 60°

Cited by 9 publications

References 12 publications

Hybrid Films from Blends of Castor Oil and Polycaprolactone Waterborne Polyurethanes

Hybrid Films from Blends of Castor Oil and Polycaprolactone Waterborne Polyurethanes

UV-curable self-matting waterborne polyurethane acrylate coatingviaself-wrinkled surface during curing in open-air

Synthesis and Characterization of Environmentally-Friendly Self-Matting Waterborne Polyurethane Coatings

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