• Journal of Adhesion and Interface
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• v.11 no.1
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• pp.35-40
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• 2010

In this study, solvent based polyurethane (PU) adhesives were prepared with the hydrocarbon resin and the acrylic modified hydrocarbon resin contents. The solvent based PU adhesive were increased with increasing tackifier concentration. The surface state of films showed good compatibility with increasing the PX-95 concentration but A-1100 series didn't present homogeneous phase more than 10 phr. Mechanical strength and peel strength were maximum at 5 phr tackifier concentration especially PX-95 series in solvent based PU adhesive.

• 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)

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.87-89
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• 2003

Thermoplastic polyurethane(PU)-based blend membranes were prepared by the solvent evaporation process. The gas sorption, diffusion, and permeation properties of PU-based blend membranes have been studied. The morphology of PU-based blend membranes was investigated by SEM. The result showed that phase separation occurred with increasing blend ratio. $CO_2$ permeation behaviors of blend membranes were affect by blend composition. Thermoplastic polyurethane(PU)-based membranes showed high $CO_2$ permeation and $CO_2$/$N_2$ selectivity of the blend membrane was improved with increasing the blend ratio.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.129-129
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• 2006

Conventional solvent-based polyurethane (PU) is well established for wide applications, such as textile treatments, surface coating, adhesive and so on. Due to the demands of safety, economic, and environmental protection, the solvent-based PU is restricted and has been phasing out and aqueous-based PU is becoming the world market trend, which is an environmental friendly product. The chemical resistance, physical and mechanical properties of aqueous-based PU are still not competible with solvent-based PU. Because of aqueous-based PU is a linear thermoplastic polymer with lower average molecular weight. Their improvements are normally performed by a post-curing reaction or a polymer hybridization to enhance the polymer cross-linking density. Hybridization of PU with aqueous-based epoxy resin or acrylate emulsion and then cured by a curing agent for improving the performance properties and reducing the cost of aqueous-based PU.Furthermore, a special function is added to aqueous-based PU increasing the application value, for examples, flame retardation, polymeric dyes, hydrophilic and etc.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1909-1918
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• 2014

In this experiment no solvent based polyurethane(PU) adhesives were prepared with the polyol, isocyanate, dioctyl phthalate(DOP), 2-hydroxyethylacrylate(2-HEA) and other acrylate monomers. The softenening point of the PU adhesives measured by Ring & Ball method were examined in the present study. And adhesion strength and mechanical properties such as tensile strength and 100% modulus of the PU adhesives were evaluated by Universal Test Machine. The experimental results showed that increase of both DPE-41, benzoylperoxide(BPO) and toluene diisocyanate(TDI) increased softenening point, adhesion strength, tensile strength and 100% modulus. However as DOP content increased sofenening point, adhesion strength decreased and tensile strength, 100% modulus also decreased.

• Journal of the Korean Applied Science and Technology
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• v.37 no.6
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• pp.1619-1626
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• 2020

In this study, the physical properties of water-dispersible polyurethane resins synthesized with polyammonium phosphate and HMDI were studied by coating film samples and full-grain surfaces. Solvent resistance was found to be unchanged in all samples, and in terms of tensile strength, DPU-AP3 (1.887 kgf/㎟) containing the most ammonium polyphosphate showed the lowest physical properties. The elongation rate was measured as 54 8% in the sample containing a large amount of ammonium polyphosphate. Abrasion resistance was measured as 548 mg.loss of a sample containing a lot of ammonium polyphosphate, and it was confirmed that the physical properties of the blended resin of ammonium polyphosphate and water-dispersible polyurethane were changed.

• Journal of the Korean Wood Science and Technology
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• v.52 no.3
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• pp.221-233
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• 2024

Lignin, a prominent constituent of woody biomass, is abundant in nature, cost-effective, and contains various functional groups, including hydroxyl groups. Owing to these characteristics, they have the potential to replace petroleum-based polyols in the polyurethane industry, offering a solution to environmental problems linked to resource depletion and CO₂ emissions. However, the structural complexity and low reactivity of lignin present challenges for its direct application in polyurethane materials. In this study, Kraft lignin (KL), a representative technical lignin, was fractionated with ethanol, an eco-friendly solvent, and mixed with conventional polyols in varying proportions to produce polyurethane films. The results of ethanol fractionation showed that the polydispersity of ethanol-soluble lignin (ESL) decreased from 3.71 to 2.72 and the hydroxyl content of ESL increased from 4.20 mmol/g to 5.49 mmol/g. Consequently, the polyurethane prepared by adding ESL was superior to the KL-based film, exhibiting improved miscibility with petrochemical-based polyols and reactivity with isocyanate groups. Consequently, the films using ESL as the polyol exhibited reduced shrinkage and a more uniform structure. Optical microscope and scanning electron microscope observations confirmed that lignin aggregation was lower in polyurethane with ESL than in that with KL. When the hydrophobicity of the samples was measured using the water contact angle, the addition of ESL resulted in higher hydrophobicity. In addition, as the amount of ESL added increased, an increase of 7.4% in the residual char was observed, and a 4.04% increase in Tmax the thermal stability of the produced polyurethane was effectively improved.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1235-1242
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• 2019

In this study, prepolymer was synthesized through the reaction of isoporon diisocyanate (IPDI) and dimethylolbutanoic acid (DMBA) based on poly (tetramethylene ether) glycol (PTMG) for the synthesis of water-soluble polyurethane to be used as a leather surface coating applied with ethyl acetate and piperazine. Thereafter, the piperazine was chain-extended with 0.01 M, 0.03 M, 0.05 M, and 0.07 M in the water-dispersed resin, and the tensile strength, elongation, CV (cyclic voltammetry), and solvent resistance analysis were performed. Tensile strength of the prepared sample was measured at 5.422 kg_f/㎟ when the piperazine content was 0.07M, and elongation was measured as 587% when the piperazine was 0.01M. Solvent resistance analysis showed the same solvent resistance regardless of piperazine content, and the redox potential was changed according to piperazine content through CV measurement.

• Journal of the Korean Chemical Society
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• v.35 no.2
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• pp.128-134
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• 1991

Previous matrices of potassium ion selective electrodes are generally based on PVC. In this study, however, the electrode membrane was prepared with polyurethane matrix containing potassium tetraphenyl borate as sensing materials and D-18-Crown-6 and 2-nitrophenyl-n-alkylethers as solvent mediator. The average life time of the K$^+$-selective electrode based on polyurethane was 75 days which is significantly longer than PVC based one. The slope factor in linear dynamic range ($1{\times}10^{-1}\;{\sim}\;1{\times}10^{-4}$ M) was 52 mV/decade. The electrode has been successfully applied to find end point in potentiometric titration of K$^+$ with tetraphenyl borate solution in the sea water, even in the presence of several interfering cations$(NH^{4+},\;Na^{+},\;Li^{+},\;Ca^{2+},\;Mg^{2+},\;Cu^{2+}$).