• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.73-79
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• 2013

Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.349-357
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• 1993

Polyarylate(PAR)-nylon 6 block copolymers of various block lengths were prepared by the anionic polymerization of ${\varepsilon}$-caprolactam using the polymeric activator from hydroxy-difuncrtional PAR and toluene diisocyanate. Phase separated morphology of PAR-nylon 6 block copolymer was suggerted from the thermal properties measured by differential scanning calorometry(d.s.c.). Partial miscbility between PAR block and nylon 6 block of the block copolymers was more evident at shorter length of constituent blocks. In binary blends of PAR-nylon 6 block copolymer with PAR or nylon 6 homopolymer, molecular-level mixing of homopolymers with corresponding blocks of block copolymer was supposed from the thermal properties measured by d.s.c..

• Applied Chemistry for Engineering
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• v.8 no.2
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• pp.339-346
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• 1997

Liquid crystalline polyurethanes were prepared from 1,4-bis(6-hydroxyhexoxy)benzene (BHB6) and 2,5-tolylene diisocyanate (2,5-TDI) solution polymerization in dimethylformamide produced intrinsic viscosities in the range 0.26 and $0.42d{\ell}/g$. The polyurethanes were investigated by DSC, Polarizing microscopy, X-ray, $^1H$-NMR and IR spectroscopy. Polyurethanes of two different molecular weights were studied in detail and these will be referred to as low molecular weight and high molecular weight. Polyurethane 2,5-TDI/BHB6 with $[{\eta}]=0.26d{\ell}/g$ prepared from BHB6 and 2,5-TDI, exhibited monotropic liquid crystallinity, although these polyurethanes contained no mesogenic core unit. For example, LCPU-L(low molecular weight) exhibited $T_{I-LC}$ of $122^{\circ}C$ $T_{LC-K}$ $89^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.38 no.5
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• pp.414-420
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• 2010

The effect of polymeric diphenyl methane-4,4-diisocyanate (pMDI) or 1,6-hexamethylene diisocyanate (HDI) in the UMF resin was discussed for improvement of the dry and wet shear strengths of plywood manufactured from high moisture content veneers. The curing behavior of UMF resin by pMDI or HDI content was examined by DSC and TGA, and its adhesion performance was evaluated by dry and wet shear strength tests of plywood. With the increase of pMDI content in the UMF resin, the curing temperature, reaction enthalpy (${\Delta}H$), and thermal stability consistently increased. With the increase of HDI content in the UMF resin, however, the curing temperature and reaction enthalpy (${\Delta}H$) decreased consistently and the thermal stability slightly increased in the range of 200 to $400^{\circ}C$ but decreased beyond $400^{\circ}C$. Also, the dry tensile shear strength increased up to the pMDI content of 5% and then decreased with its further addition but the wet tensile shear strength showed slight tendency to increase with the increase of pMDI content in the UMF resin. As the HDI content increased, however, the dry and wet tensile shear strengths of plywood consistently increased.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.73-82
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• 1990

Rosin-maleic anhydride adduct (RMA) was synthesized from rosin and maleic anhydride. The polyamideimides were obtained by reacting the adduct with two aromatic diisocyanates using sodium methoxide as catalyst. The yield and the inherent viscosity of polymers obtained by the reaction in NMP solvent were low because of the possible reaction of NMP solvent with diisocyanate monomer. The polymers were synthesized in solvent mixture of NMP and cosolvents such as xylene, acetophenone, benzonitrile, and nitrobenzene in order to minimize the side reaction of NMP with diisocyanates. The yield of polymer obtained by the reaction in NMP-nonpolar cosolvent mixtures was about 70% and that obtained by the reaction in NMP-polar cosolvent mixtures was over 90%, respectively. The polymers were either amorphous or poorly cystalline, and soluble only in highly polar solvents. The inherent viscosity of polymers ranges from 0.12-0.26dl/g. The results of thermal analysis showed that the polymer had good thermal stability with initial decomposition temperature over $330^{\circ}C$.

• Polymer(Korea)
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• v.30 no.5
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• pp.437-444
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• 2006

Reactive hydroxypropyl methylcellulose phthalate (reactive HPMCP) was synthesized by using a stepwise urethane reaction with isophorone diisocyanate (IPDI) and 2-hydroxyethyl moth acrylate (HEMA). Molecular weight, acid number, and critical micelle concentration (CMC) of the synthesized reactive HPMCP and pristine HPMCP were measured and used as a polymeric surfactant in the emulsion polymerizations of styrene. In the preparation of HPMCP-hybrid poly styrene nanoparticles, 6, 9, 12, 18, and 24 wt% of HPMCPs were introduced, and the maximum rate of polymerization ($R_{p,max}$), the average number of radicals per particle (n), particle size distribution were investigated. In addition, core - shell morphology of the nanoparticles were observed by using TEM and their thermal stabilities were measured by using TGA. Reactive HPMCP showed higher $R_{p,max}$, smaller particle size, larger values of n and gel contents as compared with pristine HPMCP, due to the vinyl groups from HEMA, which can be reacted with styrene oligomers, in the reactive HPMCP.

• Polymer(Korea)
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• v.35 no.2
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• pp.183-188
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• 2011

Pentaerytritol triacrylate (PETA) was synthesized by a condensation reaction between pentaerytritol and acrylic acid. The highest yield of PETA was obtained when heptane was used as a solvent under the 1:4 mole ratio of pentaerytritol and acrylic acid. The 6-functional urethane acrylates(UA) were also synthesized by a condensation reaction between PETA and diisocyanate. Cured films were prepared from the mixtures of UA oligomer, reactive diluents and UV initiator to investigate their physical properties. The thermal stability of the aliphatic urethane acrylate was better than that of the aromatic urethane acrylate. The UA-2 showed good hardness and scratch resistance properties while the UA-l with a high degree of curing density exhibited a better chemical resistance. All the UA oligomers showed fairly good adhesion strengths but the other physical properties of UA-3 were poor due to its low curing density.

• Polymer(Korea)
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• v.35 no.2
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• pp.171-175
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• 2011

Isophorone diisocyanate(IPDI), polytetramethylene glycol 1000 (PTMG1000), and N-methyl diethanol amine (MDEA) were applied to prepare cationic polyurethane water dispersions (PUD). Various neutralizers and chain extenders were introduced in order to investigate property changes, such as particle size, viscosity, $T_g$, tensile strength, and water swellability, depending on chemical structure of those chemicals. While the PUDs neutralized by acetic acid showed a typical elastomeric behavior, the others used with hydrochloride presented crystalline behavior. Among chain extenders isophorone diamine (IPDA) provided the best mechanical property. The particle size of the PUD neutralized with HCl was smaller than that with acetic acid. It is believed that this is attributed to the size difference of counter ions. The PUD chain-extended with hydrazine had the smallest particle size.

• Polymer(Korea)
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• v.36 no.5
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• pp.622-627
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• 2012

This study focuses on mechanical property enhancement and volatile organic compounds (VOCs) reduction characteristic of environmentally-friendly waterborne coatings. We synthesized a series of organic-inorganic hybrid waterborne polyurethanes by using poly(tetramethylene glycol) 2000, polycarbonate diol 2000, isophorone diisocyanate, dimethylolpropionic acid and titanium dioxide. The study on the effects of the R ratio([NCO]/[OH]) and inorganic contents on environmentally-friendly waterborne coatings showed that the R ratio with more than 1.5 is appropriate due to arrangement of hardsegments. The applied $TiO_2$ on films reduced volatile organic compounds (VOCs).

• 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.