• Journal of Adhesion and Interface
• /
• v.16 no.4
• /
• pp.156-161
• /
• 2015

In this study, waterborne polyurethane acrylate were synthesized with polyester polyol, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylol propionic acid (DMPA), acrylate monomer to improve the properties and peel strength. In addition, the properties of the synthesized waterborne polyurethane acylate was evaluated through FT-IR, particle size analysis, UTM, peel strength. As the acrylic acid content increased, particle size increased. In the results of mechanical properties, when the acrylic acid contents increased, tensile strength was increased but elongation was decreased. All peel strength was improved as the acrylic acid contents of WPUA and acrylate ratio of PU/acrylate increased. Optimum peel strength obtained when acrylic acid was 0.5 wt%.

• Journal of Adhesion and Interface
• /
• v.17 no.2
• /
• pp.67-71
• /
• 2016

In this study, low-viscosity polyurethane hot-melt were synthesized with polyether polyol / polyester polyol, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), 2-butanone oxime (MEKO) to improve the properties and peel strength. The properties of the synthesized low-viscosity polyurethane hot-melt was evaluated through FT-IR, viscosity meter and UTM. When the content of the reactive diluent increases and the NCO-blocked prepolymer decreases, the viscosity of low-viscosity polyurethane hot-melt adhesive was increased. When the ratio of OH-terminated oligomer, NCO-blocked prepolymer and content of reactive diluent is 1 : 0.5 : 0.5, low-viscosity polyurethane hot-melt showed 1.1 kgf/cm peel strength.

• Journal of Adhesion and Interface
• /
• v.11 no.3
• /
• pp.100-105
• /
• 2010

In this study, polyurethane dispersion was prepared by polyester polyol, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylolpropionic acid (DMPA), and monomeric diol. The effect of various monomeric diol, polyol/monomeric diol molar ratio and DMPA contents on the properties of polyurethane dispersion were investigated. As the molecular weight of monomeric diol and monomeric diol molar ratio increased, $T_g$ gradually increased. And when DMPA contents increased, also $T_g$ gradually increased. In the results of mechanical properties, when the molecular weight of monomeric diol, monomeric diol molar ratio of polyol/monomeric diol and DMPA contents increased, tensile strength was increased. Finally, optimum peel strength obtained when polyol/monomeric diol ratio was 8 : 2.

• Convergence Security Journal
• /
• v.7 no.4
• /
• pp.61-72
• /
• 2007

We developed a convenience-featured Web browser which is intended to enhance Web users' convenience. The integrated convenience functions are VPV(Visited Page Viewer), APV(Aligned Page Viewer), USC(User Specified Capture), and VAC(Video and Audio Converter) which is the most important feature of FLV(FLash Video file) in UCC (User Created Contents). The four functions are considered ad the most needed functions to the Web users and we referred to the opinion of frequent and advanced Web users. We addressed important algorithms and techniques in terms of the implementation of the above four functions. The implementation methods based on the MDI application using rendering technique same as in Internet Explorer 6.0 are shown with codes. The results of implementation is compared with the survey conducted on 134 Computer Science and Multimedia Engineering major students. All four integrated functions are considered to be useful.

• Journal of the Korean Institute of Gas
• /
• v.12 no.3
• /
• pp.38-42
• /
• 2008

Effect of polyol structure and NCO index on adhesion of PU adhesive at room ($25^{\circ}C$) and extremely low temperature ($-190^{\circ}C$) was investigated. At room temperature adhesive strength of PU adhesive tends to decrease as molecular weight of polyol increases, however, the strength at $-190^{\circ}C$ shows opposite tendency. Adhesive strength of the PU turned out to be directly proportional to the amount of MDI. PU containing aliphatic polyol was higher in shear strength at $-190^{\circ}C$ and the strength of PU with aromatic polyol was higher at room temperature.

• Membrane Journal
• /
• v.15 no.1
• /
• pp.44-51
• /
• 2005

Polyurethane-polysiloxanes (PU/PDMS) was synthesized using 4,4'-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) to overcome the weakness to the organic chemicals. The composite membranes were prepared onto porous poly(tetrafluoroethylene) (PTFE) supports. In vapor permeation experiments, the flux increased with increasing operating temperatures and feed concentrations while the separation factors showed the opposite trend, so-called 'trade-off'. In this study, the effect of the flux on the operating temperatures was not severe since the content of the soft segments is fairly higher than that of the hard segments. The composite membrane type of PU/PDMS maintained high flux and separation factor as well when comparing with the dense type membranes.

• The Korea Journal of Herbology
• /
• v.31 no.6
• /
• pp.29-35
• /
• 2016

Objectives : Blood stasis (BS) is related to be caused by blood circulation and stagnation which are cancer, atherosclerosis and hyperlipidemia in traditional medicine. We extracted 3 kinds of BS formula; Seogakjihwang-tang (SGT), Tonggyuhawlhyul-tang (THT), Hyulbuchukeo-tang (HCT). This study was conducted to investigate whether the 3 kinds of herbal formula extracts have inhibitory efficacy association with anti-adipogenesis. Methods : To investigate the anti-adipogenesis, we used the mouse fibroblast cell line, 3T3-L1 which differentiated into adipocytes in response to insulin, IBMX and dexamethasone (MDI). Cytotoxicity of herbal formula extracts were examined by CCK-8 kit. Intracellular lipid droplets were detected by Oil-Red-O staining. Triglyceride (TG) and leptin were measure using elisa kit. Results : The yield of water extracts was 14.62% (SGT), 21.27% (THT), 20.02% (HCT). Lipid accumulation was reduced significantly by 3 kinds of herbal formula compared to control. Especially, THT and HCT decreased lipid droplet, respectively at all concentration. The TG and leptin were also inhibited by 3 kinds of herbal formula. The IC50 of TG were $280.51{\mu}g/m{\ell}$ (SGT), $52.62{\mu}g/m{\ell}$ (THT), $313.99{\mu}g/m{\ell}$ (HCT). The IC50 of leptin were $348.76{\mu}g/m{\ell}$ (SGT), $164.02{\mu}g/m{\ell}$ (THT), $257.00{\mu}g/m{\ell}$ (HCT). THT was better than other herbal formula on anti-adipogenesis. Conclusion : kinds of herbal formula inhibited adipogenesis in MDI-induced 3T3-L1 adipocytes, as indicated by the significant reduction in TG and leptin concentration without cytotoxicity. Therefore, 3 kinds of herbal formula for BS might act as a therapeutic agent for preventing lipid diseases, such as obesity and atherosclerosis.

• Journal of Adhesion and Interface
• /
• v.8 no.4
• /
• pp.1-7
• /
• 2007

Waterborne polyurethane (WPU) which is environment friendly has been rapidly used in coating and adhesive industries. However, the WPU is deficient in chemical resistance, thermal resistance, and mechanical property compared to solvent-based polyurethane. In this study, the WPU was synthesized from two types of polyester polyols, 4,4-dicyclohexylmethane diisocyanate ($H_{12}MDI$), dimethylolpropionic acid (DMPA), triethylamine (TEA) and ethylenediamine (EDA), organophilic nanoclay. The thermal stability, mechanical property of the WPU nanocomposite dispersion increased with increasing clay concentration. Especially, their peel strength showed their maximum value at 3 wt% of organophilic nanoclay contents.

• Elastomers and Composites
• /
• v.33 no.4
• /
• pp.267-273
• /
• 1998

Isocyante terminated urethane prepolymers were synthesized by the reaction of 4,4'-dimethyl phenyldiisocyanate(MDI) and ester type polyols such as ethylene glycol/ butanediol adipate(EBA), neopentylglycol/butanediol adipate (NBA) and hexanediol adipate (HA) . All of the NCO-terminated urethane prepolymers are solid at room temperature, but they become mobile enough to be disposed onto a substrate upon heating about $80^{\circ}C$. Subsequently, they are solidified and cured through the reaction with moisture. Tensile behavior of the ore-thane hotmelt exhibits characteristic features depending on the type of polyol. The adhesive strength determined by single lap shear joint is higher in order of HA, NBA and EBA based ore thane hotmelt, which can be correlated with the magnitude of breaking energy of the cured films. The failure mode are cohesive for all cases and the adhesive strength increases as the test is performed faster. This indicates that the strength of the adhesive joint is primarily dependent upon the bulk properties of the adhesives.

• Polymer(Korea)
• /
• v.38 no.1
• /
• pp.9-15
• /
• 2014

Polyamide4 (PA4)-polyurethane (PU)-PA4 triblock copolymers were synthesized by isocynated (NCO)-terminated PU prepared from 4,4'-diphenyl methane diisocyante (MDI) and polytetramethylene glycol (PTMG) as an initiator and potassium pyrrolidonate (P-py) as a catalyst for anionic ring opening polymerization of 2-pyrrolidone. Subsequently copolymer was controlled to contain different or same molecular weight of PA4 hard block with same or different molecular weight of PU soft block in order to investigate the effects of those differences on various properties of triblock copolymers as a thermoplastic elastomer. As the results shown in typical properties of block copolymeric elastomers, the mechanical strength and melting point ($T_m$) of the copolymers increased with an increase in molecular weight of PA4 block while the elongation at break increased with an increase in that of PU block.