• Tribology and Lubricants
• /
• v.14 no.4
• /
• pp.72-78
• /
• 1998

In this work, the effects of binder materials on the tribological behavior were experimentally evaluated for air curable MoS$_2$bonded film lubricants. The binders tested were basically alkyd and acryl based resins, and also were modified by nitro-cellulose in various weight percentages. Effects on the binder ratio to solid lubricants and the molecular weight of binders were also investigated in all aspects of the tribological behavior. For the tests, LFW-1 and Falex tester were used to measure mainly the endurance life and load carrying capacity of bonded lubricants. Results showed that lubricants of methacrylic resin has the better performance than those of other resins, and also the properties of lubricants both of alkyd and acrylic resins could be improved by modification with nitro-cellulose. It was also shown that the optimum ratio of nitro-cellulose related closely to the binder material and the testing machine.

• Proceedings of the Korean Fiber Society Conference
• /
• 1996.10a
• /
• pp.468-472
• /
• 1996

A series of UV-curable polyurethane acrylate ionomer were synthesized from isophorone diisocyanate(IPDI), poly(tetramethylene ether glycol)(PTMG), 2,2-bis(hydroxymethyl)propionic acid (CMPA), triethylamine(TEA), 2-hydroxy ethyl acrylate (HEA), and dibutyl tin dilaurate (DBT) as a catalyst. 2,2-dimethoxy-2-phenyl acetophenone(DMPAP) was used as a photoinitiator. The films of UV-cured polyurethane acylate ionomer were prepared by casting the formulated materials onto a glass plate at room temperature and cured using a medium pressure mercury lamp (80 W/cm, max = 365nm). Effects of DMPA content, molecular weight of PTMG and degree of neutralization on the properties were invesigated. It is found that the storage modulus increased with increasing DMPA content. The glass transition temperature of sample A shifted to higher temperature as the content of DMPA was increased. Tensile modulus also increased with increasing DMPA content. Modulus and Tg decreased with increasing molecular weight of PTMG form 650 to 2000. With increasing the degree of nutralizaion, ionomers exhibited improved modulu.

• Macromolecular Research
• /
• v.13 no.4
• /
• pp.362-365
• /
• 2005

• Fibers and Polymers
• /
• v.2 no.3
• /
• pp.122-128
• /
• 2001

UV-curable polyurethane acrylate prepolymers were prepared from diisocyanates [isophorone diisocyanate (IPDI), 2,4-toluene diisocyanate (TDI), or 4,4'-dicyclohexylmethane diisocyanate (H$_{12}$MDI)], diols [ethylene glycol (EG), 1,4-butane diol (BD), or 1,6-hexane diol (HD)], polypropylene glycol as a polyol. UY-curable mixtures were formulated from the prepolymer (90 wt%), reactive diluent monomer trimethylol propane triacrylate (10 wt%). and photoinitiator 1-hydroxycy-clohexyl ketone (3 wt% based on prepolymer/diluent). The effects of different diisocyanates/low molecular weigh dial on the dynamic mechanical thermal properties and elastic recovery of UV-cured polyurethane acrylate films were examined. The tensile storage modulus increased a little in the order of EG > BD > HD at the same diisocyanate. Two loss modulus peaks for all samples are observed owing to the glads transition of softs segments ($T_gh$) and the glass transition temperature of hard segments ($T_gh$). For the same diisocyanate, $T_gh$, decreased, however, $T_gh$ increased, in the order of HD > BD > EG. The elastic recovery also increased in the order of HD > BD > EG at the same diisocyanate. In case of same diols, $T_gh$ increased in the order of $H_12$MDl > TDI > IPDI significantly. The ultimate elongation and elastic recovery increased in the order of TDI > IPDI > $H_12$MDl at the same diol.l.

• Korean Chemical Engineering Research
• /
• v.59 no.2
• /
• pp.165-173
• /
• 2021

Anti-glare (AG) coating films are applied to various display fields such as liquid crystal displays, LED lighting, and touch panels. In this study, micrometer-sized silica particles were added as fillers in the UV-curable coating solutions to provide anti-glare effect. During this process, the effects of the particle size, content, stirring time, and mixing ratio of silica particles of different sizes were investigated on the haze values and visible light transmittance of the coating films. As a result, as the size of the silica particles increased and the content of the silica particles increased, the haze values increased, but the visible light transmittance decreased. On the other hand, the stirring time did not significantly affect the haze value and transmittance of coating films. In addition, as the mixing ratio of large-sized silica particles increased, the haze value increased, but on the contrary, the visible light transmittance decreased.

• Textile Coloration and Finishing
• /
• v.11 no.4
• /
• pp.1-7
• /
• 1999

Urethane-acrylate propelymers for secondary coating of optical fiber and high - performance material were prepared from the 4,4'-diphenylmethane diisocyanate(MDI), poly(tetramethylene oxide)glycol(PTMG, Mw 650 or 1000), 1,6-hexanediol(HD), 2-hydroxyethyl acrylate(HEA), and dibutyltin dilaurate as a catalyst. UV-Curable polyurethane acrylates were formulated from the urethane-acrylate prepolymers, three types of reactive diluents(DTs) having mono-, di-, and trifunctional-phenoxyethyl acrylate(PEA), hexanediol diacrylate(HDDA), and trimethylolpropane triacrylate(TMPTA), and 1-hydtoxycyclohexyl phenyl ketone(Irgacure 184) as a photoinitiator. The UV-cured films of polyurethane acrylates were obtained by curing using a medium-pressure mercury lamp(U W/cm, $\lambda_{max}=365\;nm)$. In this work, the effects of molecular weights of polyol and diol with low molecular weight into polymer chain on mechanical and dynamic mechanical properties of UV-cured polyurethane acrylates were studied. The structure and properties of the films obtained from the UV photopolymerization of urethane-acrylate prepolymer were investigated by FT-IR spectroscopy, dynamic mechanical measurement, tensile testing, and X-ray diffractometry.

• Macromolecular Research
• /
• v.14 no.5
• /
• pp.517-523
• /
• 2006

The effects of particle content, size and shape on the thermal conductivity (k) and adhesion properties of thermally conductive, pressure-sensitive adhesives (PSAs) were investigated. The matrix resins were thermally crosslinkable, 2-ethylhexyl acrylic polyol and ultraviolet (UV)-curable, random copolymer consisting of acrylic oligomer and various acrylates. We found that k increased with increasing diameter and particle aspect ratio, and was further enhanced due to the reduction of the interfacial thermal barrier when the coupling agent, which increases the adhesion between particles and the matrix resin, was used. On the other hand, adhesion properties such as peel strength and tack of the thermally crosslinkable resin decreased sharply with increasing particle content. However, for UV curable resin, increased particle addition inhibited the decrease in adhesion properties.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.3
• /
• pp.196-206
• /
• 2004

The medicinal effects of 107 grains in $\boxDr$Dongeuebogam$\boxUl$ were studied for the development of healthy Korean traditional meal. Their efficacy, way of use, fact of taboo were mentioned in it. Grains were utilized and processed as tang(soup), jook(porridge), boonmal(powder), kunjo(drying), etc. Most of grains had sweet taste and mild nature(not hot and not cold) based on Eum-Yang-Oh-Haeng theory. The medicinal effects of grains described in $\boxDr$Dongeuebogam$\boxUl$ were the protection of stomach and intestine, enhancement of physical activity, protection of hair and skin, thirst elimination, treatment of several diseases, maintenance of health, etc.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.29 no.6
• /
• pp.345-351
• /
• 2019

Recently, ink-jet printing technology has been applied for various industries such as semiconductor, display, ceramic tile decoration. Ink-jet printing has advantages of high resolution patterning, fast printing speed, high ink efficiency and many attempts have been made to apply functional materials with excellent physical and chemical properties for the ink-jet printing process. Due to these advantages, research scope of ink-jet printing is expanding from conventional two-dimensional printing to three-dimensional printing. In order to expand the application of ink-jet printing, it is necessary to optimize the rheological properties of the ink and the interaction with the substrate. In this study, photo curable ceramic complex ink containing nano silica particles were synthesized and its printability was characterized. Contact angle of the photo curable silica ink were modified by control of the ink composition and the surface property of the substrate. Effects of contact angle on printing resolution and three-dimensional printability were investigated in detail.

• Journal of Adhesion and Interface
• /
• v.12 no.2
• /
• pp.47-55
• /
• 2011

UV-curable coatings have been used in various industries due to their advantages such as high mechanical property, good solvent resistance, fast curing process and low volatile organic compounds. However, a lack of flexibility of UV-cured films is a weak point for the pre-coated system of roll-to-roll process. In this study, UV-curable polycarbonate-based methacrylates were synthesized with polycarbonate diol, isophorone diisocyanate and 2-hydroxyethylmethacrylate to improve flexibility of the UC-cured films. The effects of polyol molecular weight, content of photoinitiator and monomers on the UV-curing behavior, flexibility and properties were investigated. The UV-curing behavior was measured by a photo-DSC, the pendulum hardness, tensile strength, viscoelastic properties were also evaluated.