• Macromolecular Research
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• v.13 no.5
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• pp.418-426
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• 2005

One-pack cross-linkable nanocomposites of waterborne methyl ethyl ketoxime (MEKO)-blocked aromatic polyurethane dispersion (BPUD) reinforced with organoclay (quaternary ammonium salt of Cloisite 25A) were synthesized by the acetone process using 4,4'-methylenedi-p-phenyl diisocyanate (MDl), poly(tetramethylene) glycol (PTMG), dimethylol propionic acid (DMPA), and methyl ethyl ketoxime (MEKO). Particle size, viscosity, and storage stability of these nanocomposites were investigated. TEM and XRD studies confirmed that the silicate layers of organophilic clay were exfoliated and intercalated at a nanometer-scale in the BPUD matrix.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.5-8
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• 2001

Waterborne Polyurethane dispersions continue to show growth in commercial usage due to the ever increasing environmental legislation to reduce VOC in Coating and adhesive materials. The transition from solvent-based to waterborne Polyurethane(WPu) has also been facilitated by advances in both the chemistry and technology employed and the formulation expertise required. (omitted)

• Macromolecular Research
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• v.15 no.1
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• pp.22-30
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• 2007

High water vapor permeable coating materials were prepared by blending aqueous poly(vinyl alcohol) (PVA) solution with waterborne polyurethane-urea (WBPU) dispersions synthesized by prepolymer mixing process. Stable WBPU/PVA dispersions were achieved at PVA content below 30 wt%. As the water soluble polymer PVA content increased, the number and density of total micro-pores (tunnel-like/isolated micro-pores) formed after the dissolution of PVA in water increased, and the water vapor permeability of coated Nylon fabric also increased significantly. Using WBPU/water soluble polymer PVA blends as a coating material and then dissolving PVA in water was confirmed to be an effective method to obtain prominent breathable fabrics.

• Elastomers and Composites
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• v.57 no.3
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• pp.100-106
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• 2022

Waterborne polyurethane-acrylate(WPUA) dispersions were prepared by surfactant-free emulsion polymerization in a two-step process. In the first step, polytetrahydrofuran, isophorone diisocyanate, dimethylol proponic acid, and 2-hydroxyethyl methacrylate were used to synthesize a vinyl-terminated polyurethane prepolymer. In the second step, styrene, methyl methacrylate, butyl acrylate, and different multi-functional crosslinkers were copolymerized. 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate were used as the crosslinkers, and their effect on the mechanical and thermal properties of WPUA was investigated. Overall, as the number of functional groups of the cross-linker increased, the gel fraction improved to 79.26%, the particle size increased from 75.9 nm to 148.7 nm, and the tensile strength was improved from 5.86 MPa to 12.40 MPa. In thermal properties, the glass transition temperature and decomposition temperature increased by 9.9℃ and 18℃, respectively. The chemical structures of the WPUA dispersions were characterized by Fourier-transform infrared spectroscopy. The synthesized WPUA has high potential for applications such as coatings, leather coatings, adhesives, and wood finishing.

• Journal of Environmental Science International
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• v.16 no.8
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• pp.891-896
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• 2007

Waterborne polyurethane dispersions (WPUD) were prepared by poly(ethylene glycol) adipate as the polyester type, ${\alpha},{\omega}-hydroxyalkyl$ terminated polydimethylsiloxane (PDMS-diol) as the polysiloxane type, hexamethylene diisocyanate, and isophorone diisocyanate, dimethylol propionic acid. The effects of PDMS-diol contents on the particle size, thermal and surface properties of WPUD were investigated. The structures of the synthesized WPUD were confirmed using by FT-IR. The surface, thermal and mechanical properties were investigated by measuring the contact angles, DSC, TGA and UTM. As PDMS-diol contents increased, the particle size, the contact angle, and the elongation was increased, while the tensile strength was decreased. Also the thermal stabilities of the synthesised WPUD were increased as PDMS-diol contents increased.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.632-638
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• 2012

Waterborne polyurethane dispersions (PUD) were synthesized from isophorone diisocyanate (IPDI), polycarbonate diol (PCD) and dimethylol propionic acid (DMPA) as starting materials. Subsequently, waterborne polyurethane-acrylic hybrid solutions were prepared by reacting the PUD with different amounts of the mixture of acrylate monomers, HEMA (2-hydroxyethyl methacrylate) and MMA (methyl methacrylate). As a result, the average particle size of waterborne polyurethane-acrylic hybrid solutions was increased with increasing the addition amounts of acrylate monomers. Also, the prepared coating films from waterborne polyurethane-acrylic hybrid solutions showed better abrasion resistance and chemical resistance than those of pure PUD.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.410-416
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• 2012

Waterborne polyurethane dispersions (PUD) were synthesized from isophorone diisocyanate (IPDI), polycarbonate diol (PCD) and dimethylol propionic acid (DMPA) as starting materials. Subsequently, polyurethane-acrylic hybrid solutions were prepared by reacting the PUD with different types of acrylate monomers, such as HEMA (2-hydroxyethyl methacrylate):MMA (methyl methacrylate), HEMA:BA (butylacrylate), HEMA:BMA (butyl methacrylate), HEMA:HEA (2-hydroxyethyl acrylate), HEMA:PETA (pentaerytritol triacrylate) mixture. Also, the effects of acrylate types on the chemical resistance and the abrasion resistance of polyurethane-acrylic hybrid solutions were investigated. The test results showed that the HEMA:MMA mixture had the strongest chemical resistance, while the HEMA:PETA mixture had the strongest abrasion resistance among several types of acrylate mixtures.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.427-434
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• 2012

Waterborne polyurethane dispersions (PUD) were synthesized from poly (carbonate diol), isophrone diisocyanate and dimethylol propionic acid at different NCO/OH molar ratios. Subsequently, the PUD was mixed with different types of alkali metal salts ($LiClO_4$, $NaClO_4$, and $KClO_4$) to prepare antistatic waterborne polyurethane coating solutions. Effects of the types and amounts of alkali metal salts were investigated on the surface resistances of the resulting coating films. The surface resistances of coating films were decreased with increasing the amounts of alkali metal salts added in the PUD. The coating films prepared with the same amount of alkali metal salts showed increased ionic conductivity with the order of $LiClO_4$ > $NaClO_4$ > $KClO_4$. Also, the surface resistances of coating films were increased with increasing the molar ratios of NCO/OH in the PUD.

• Elastomers and Composites
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• v.35 no.4
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• pp.281-287
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• 2000

Waterborne polyurethane(PU) microgel dispersions were synthesized with different mole ratio of polytetramethylene glycol(PTMG) to dimethylol propionic acid(DMPA). Particle size distribution, thermal and mechanical properties of the PU microgels were investigated. Particle size of the microgels was distributed in the range of $98{\sim}$680{\mu}m$ and decreased with increasing the mole ratio of DMPA and 1,2,6-hexanetriol. Glass transition temperature and melting temperature of the microgels were in the range of $-79.7 {\sim}-78.1^{\circ}C$, $22{\sim}24^{\circ}C$ respectively. Tensile strength and elongation of the PU microgel films were maximum in the case of 60/40 mole ratio of PTMG/DMPA.

• Journal of Adhesion and Interface
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• v.7 no.4
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• pp.53-59
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• 2006

The paper highlights technical advances and introduces recent innovations such as smart curing laminating adhesives for flexible packaging with low migration rates of aromatic isocyanates and amines. Latent reactive one-part systems on the basis of surface deactivated solid isocyanates open up new dimensions for heat setting adhesives and waterborne PU dispersions. The new generation of Purmelt Micro Emission adhesives contains less than 0.1% of MDI monomer, thereby drastically reducing the emission of hazardous isocyanate vapors during processing and setting a significantly improved technical standard in occupational safety. Once again, polyurethane adhesives have demonstrated their unique ability to adapt to new process, product, safety and environmental requirements.