• 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.

• Journal of Adhesion and Interface
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• v.23 no.2
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• pp.33-38
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• 2022

In this study, we report on the synthesis and properties of eco-friendly waterborne polyurethane (WPU) according to bio-polyol contents. It was successfully synthesized by the different polyester polyol (DT-1040) and castor oil based polyol (COP) ratios. The glass transition temperature (Tg) of the synthesized bio polyol based waterborne polyurethane was around -70 ℃ and -30 ℃, and it was confirmed that the Tg range was widened as the COP content increased. In addition, as the COP content increased, the tensile strength decreased, and optimum adhesive strength showed when DT-1040:COP ratio was 7:3.

• Journal of Adhesion and Interface
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• v.22 no.2
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• pp.39-46
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• 2021

Waterborne polyurethanes (WPU) was synthesized using polyester polyol and polycarbonate polyol containing 3-Methyl-1,5-pentanediol (MPD) in a branched structure. To compare physical properties, WPUs were synthesized using polyester polyol obtained from 1,4-butanediol (BD) and adipic acid and polycarbonate polyol obtained from 1,6-hexane diol (HD)/ 1,4-butanediol (BD). This study investigated the effect of polyol molecular structure (molecular structure in soft segments) on the physical properties of WPUs. In the case of WPUs synthesized using polyols containing MPD, 100% modulus and tensile strength were lower than that without MPD, and elongation was higher. The transparency of WPU films with MPD were slightly better than WPU films without MPD.

• Journal of Adhesion and Interface
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• v.23 no.1
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• pp.8-16
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• 2022

In this study, self-healable waterborne polyurethane (SH-WPU) as shoes and coating materials with self-healable disulfide functionalities was synthesized by mixing polyether polyol to impart excellent durability and heat resistance and polycarbonate polyol to impart excellent mechanical properties. The synthesized SH-WPU was characterized by fourier transform-infrared spectroscopy (FT-IR), and physical and self-healing properties were confirmed through universal testing machine (UTM) and scanning electron microscope (SEM) measurements. Tensile strength and hardness were increased and elongation was decreased by using polycarbonate polyol. In addition, as a result of comparison of thermal properties, thermal stability has been increased as the content of polycarbonate polyol increased. The healing efficiency showed the highest efficiency when poly(tetramethylene ether)glycol : polycarbonate polyol = 0.75 : 0.25, and it was confirmed that the damaged part was healed through surface observation using a microscope and SEM.

• Clean Technology
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• v.24 no.3
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• pp.190-197
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• 2018

Various waterborne polyurethanes (WPU) with three different types of polyol such as ester type polyol [adipic acid (A)/BD/3-methyl-1,5-pentandiol (MPD) and A/BD]//carbonate type polyol (C/HD/MPD, C/HD, C/BD)//ether type polyol (PTMG) were prepared in this study. This study focused on the effect of polyol type on the properties of WPU. Soft segment Tg (Tgs), 100% elastic modulus and tensile strength were highest when using carbonate polyol, followed by ester polyol and ether polyol, while those of elongation showed the opposite trend. The WPU synthesized with MPD - containing polyol showed lower Tgs, 100% elasticity and strength, and higher elongation than MPD - free WPU. The % transmittance and transparency of the WPU film containing the MPD component was superior to that of the WPU film containing no MPD component, and it was found that the film based on carbonate polyol was slightly better than the film based on ester polyol and ether polyol.

• Journal of Adhesion and Interface
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• v.16 no.1
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• pp.22-28
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• 2015

In this study, Waterborne polyurethanes (WPU) using Epoxy group were synthesized with polyester polyol, epoxy resin, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylol propionic acid (DMPA) to improve the hydrolysis resistance and adhesion. In addition, the properties of the synthesized waterborne polyurethane was evaluated through DSC, UTM, adhesion strength. Tg of the synthesized waterborne polyurethane is shown in the vicinity of $-50^{\circ}C$. Tg were increased with as epoxy resin contents increased. The tensile strength was increased as the content of epoxy resin increases, elongation was decreased. Optimum adhesion and hydrolysis-resistance strength were obtained when polyol : epoxy ratio was 99 : 1.

• 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.