• Macromolecular Research
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• v.14 no.3
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• pp.373-382
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• 2006

A series of crosslinkable, waterborne polyurethanes (I-WBPUs) were prepared by in-situ polymerization using isophorone diisocyanate (IPDI)/poly(tetramethylene oxide) glycol (PTMG, $M_n$=2,000)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA)/aminoplast[hexakis(methoxymethyl)melamine (HMMM)] as a crosslinking agent. Typical crosslinkable, waterborne polyurethanes (B-WBPUs) blended from WBPU dispersion and aqueous HMMM solution was also prepared to compare with the I-WBPUs. The crosslinking reaction between WBPU and HMMM was verified using FTIR and XPS analysis. The effect of the HMMM contents on the dynamic mechanical thermal, thermal, mechanical, and adhesion properties of the I-WBPU and B-WBPU films were investigated. The storage modulus(E'), glass transition temperatures of the soft segment ($T_{gs}$) and the amorphous regions of higher order ($T_{gh}$), melting temperature ($T_m$), integral procedural decomposition temperature (IPDT), residual weight, $T_{10%}$ and $T_{50%}$ (the temperature where 10 and 50% weight loss occurred), tensile strength, initial modulus, hardness, and adhesive strength of both I-WBPU and B-WBPU systems increased with increasing HMMM content. However, these properties of the I-WBPU system were higher than those of the B-WBPU system at the same HMMM content. These results confirmed the in-situ polymerization used in this study to be a more effective method to improve the properties of the WBPU materials compared to the simple blending process.

• Fibers and Polymers
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• v.7 no.2
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• pp.95-104
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• 2006

In order to improve the water swelling, thermal/mechanical and adhesion properties of waterborne polyurethane (WBPU), a series of the crosslinkable WBPUs containing hydrophilic ionic component, dimethylol propionic acid (20 mole%), were prepared by in-situ polymerization using a cross-linker hexakis (methoxymethyl) melamine (HMMM). Effects of the HMMM content (2, 4, and 6 wt%) and curing temperature on these properties of the crosslinked WBPUs samples were investigated. All properties were found to increase with increasing HMMM content. It was found that the optimum curing temperature of the WBPU films and adhesives was near $120^{\circ}C$, which was not dependent on the HMMM content.

• Journal of Adhesion and Interface
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• v.18 no.4
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• pp.179-182
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• 2017

Waterborne polyurethanes(WPU) based on castor oil were successfully prepared using polycaprolactone diol(PCL), castor oil(CO) and 4,4'-methylene dicyclohexyl diisocyanate($H_{12}MDI$) as soft segment part, dimethylolbutanoic acid (DMBA) as emulsifier, and trimethylamine(TEA) as neutralizer based on different molecular weight of prepolymer. The various properties such as mechanical strength and surface reforming were evaluated using UTM, contact angle, FE-SEM based on the different molecular weight of polyol. Waterborne polyurethanes based on castor oil could be considered as a promising candidate to be applied the various adhesion fields.

• Corrosion Science and Technology
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• v.16 no.1
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• pp.49-49
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• 2017

• Polymer(Korea)
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• v.30 no.2
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• pp.152-157
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• 2006

Anionic or Zwitter-ionic waterbone polyurethanes (WPU) based on mixtures of hydroxy terminated poly-butadiene and poly(propylene glycol) were prepared and their physical properties were characterized. Particle size of WPU increased with increasing the content of HTPB. It was observed that the microphase separation of soft segments and hart segments increased with increasing the content of HTPB in the WPUs. Zwitter-ionic WPU showed stronger hydrogen bonds between molecules than anionic WPU after drying. Polyurethane films obtained after drying of WPUs exhibit besmechanical properties when the HTPB content among polyols for WPUs were 25wt%. It is postulated that such mechanical properties resulted from different microphase separation of soft segments and hard segments of polyurethane films obtainec after drying of WPUs.

• Corrosion Science and Technology
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• v.15 no.6
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• pp.297-302
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• 2016

Water-based systems are dominating the coating market because of worldwide VOCs regulations. Research is focusing especially on waterborne polyurethane (WPU) because of its unique mechanical and chemical properties. However, commercial WPU consists of linear thermoplastic polymers with polar groups on the main chain, which do not perform as well as solvent-borne PU in a two-pack system. In this study, APTES were used as a chain crosslink agent to overcome commercial WPU's limited performance. WPUs synthesized by using a sol-gel process were evaluated with FT-IR, particle analysis, TGA, tensile tests, pull-off tests, SEM, and EIS. The results showed that WPUs with added APTES had better thermal stability, mechanical properties, and water resistance than did WPUs without added APTES. Consequently, the sol-gel process increased the crosslink density of WPUs and modified the WPU's own properties.

• Fibers and Polymers
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• v.3 no.4
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• pp.153-158
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• 2002

A series of waterborne polyurethanes (WBPU) were prepared from 4,4-dicyclohexylmethane diisocyanate ($H_{12}$MDI),2,2-bis(hydroxylmethyl) propionic acid (DMPA), othylenediarnine (EDA), triethylamine (TEA), and triblock glycol [TBG, ($\varepsilon$-caprolactone)$_{4.5}$-poly(tetramethylene ether) glycol (MW= 2000)-($\varepsilon$-caprolactone)$_{4.5}$: $(CL)_{4.5}$-PTMG-$(CL)_{4.5}$, MW=3000] as a soft segment. Two melting peaks of TBG at about 14$^{\circ}C$ and 38$^{\circ}C$ were observed indicating the presence of two different crystalline domains composed of CL and PTMG dominant component. The effect of soft segment content (60-75 wt%) on the colloidal properties of dispersion, and thermal and mechanical properties of WBPU films, the water vapor permeability (WVP) and water resistance (WR) of WBPU-coated Nylon fabrics, and the adhesive strength of WBPU- coated layer and Nylon fabrics was investigated. As soft segment contents increased, the water vapor permeability of WBPU- coated Nylon fabrics increased from 3615 to 4502 g/$m^2$day, however, the water resistances decreased from 1300 to 500 mm$H_2$O.O.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.548-553
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• 2011

NCO terminated polyurethane prepolymers were synthesized from isophorone diisocyanate(IPDI), polycarbonate diol(PCD) and dimethylol propionic acid(DMPA). Subsequently, acrylic terminated polyurethanes were prepared by capping the NCO groups of polyurethane prepolymers with different types of acrylate monomers, such as 2-hydroxyethyl methacrylate(HEMA), 2-hydroxyethyl acrylate(HEA) and pentaerythritol triacrylate(PETA). The average particle sizes of the acrylic terminated polyurethane solutions were increased by capping acrylate monomers. Also, the prepared coating films showed better abrasion resistance and pencil hardness than those of pure waterborne polyurethanes. The coating film with PETA exhibited the best abrasion resistance and pencil hardness of coating films prepared with three acrylate monomers.

• Textile Coloration and Finishing
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• v.30 no.1
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• pp.9-19
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• 2018

To prepare bio-inspired antifouling coating materials having similar structure with lotus, self-crosslinkable waterborne polyurethanes emulsions containing paraffin wax (CWPU/P0, 0.25, 0.5, 1.0, 1.5, 2.0, the number indicated the wt% of wax) were prepared by an emulsifier-free/solvent free prepolymer mixing process. The as-polymerized CWPU/P emulsions containing 0 - 1.00wt% of paraffin wax were found to be stable after 4 months, however, CWPU/P emulsions containing 1.50 and 2.00wt% of paraffin wax were unstable within 1 month storage. Considering the stability of emulsions, the optimum paraffin wax content was found to be about 1wt% to obtain stable antifouling coating emulsion material. The surface topology of CWPU/P film samples was characterized by atomic force microscopy (AFM). This study examined the effect of paraffin wax content on the surface roughness, water contact angle/surface energy, water swelling, light transmittance and tensile properties of CWPU/P film samples.

• Polymer(Korea)
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• v.37 no.2
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• pp.167-176
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• 2013

Linear and cross-linked waterborne polyurethanes (WPUs) based on isophorone diisocyanate and mixed diols of poly(tetramethylene glycol)/hydroxyethyl-terminated polydimethylsiloxane (PDMS-OH) were synthesized with dimethylol propionic acid as an anionic component, trimethylolpropane as a cross-linking agent, and butanediol as a chain extender and characterized. The hydrophobicity, $T_g$, stress-strain behaviors of the linear or cross-linked siloxane-containing WPU (WPU-Si) films with different PDMS content were analyzed by using water contact shape analyzer, energy dispersive spectrometer, dynamic mechanical analyzer, and universal testing machine. The results reveal that as the PDMS content increased, the hydrophobicity of WPU-Si films increased, $T_g$ moved to higher temperature, the breaking stress increased, and the breaking strain decreased.