• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.270-280
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• 2005

To maximize a synergy effect in flame-retardancy of flame-retardant coatings, phosphorus and chlorine were introduced in polymer chains. Two-components PU flame-retardant modified polyesters (ABTTC-10C, -20C, -30C) were prepared by curing, at room temperature, of isocyanate (allophanate-trimer) and prepared modified polyesters which contain phosphorus and chlorine. To examine the film properties of the prepared flame-retardant coatings, film specimens were prepared with the prepared coatings. The film properties of ABTTC, ABTTC-10C and ABTTC-20C, which contain 0, 10 and 20wt%, 2,4-dichlorobenzoic acid (2,4-DCBA), respectively, were proved to be good, whereas the film properties of ABTTC-30C, which contains 30wt% 2,4-DCBA, were proved to be a little bit poor. Two kinds of flame retardancy tests, $45^{\circ}$Meckel burner method and LOI method, were performed. With the $45^{\circ}$Meckel burner method, three flame-retardant coatings except ABTTC showed less than 3.4 cm of char length, and showed less than 2 seconds of afterflaming and afterglow. From this result, the prepared flame-retardant coatings were proved to have the 1st grade flame retardancy. With the LOI method, the LOI values of the coatings containing more than 10wt% 2,4-DCBA were higher than 30wt%, which means that the coatings possess good flame-retardancy. From these results, it was found that synergistic effect in flame-retardancy was taken place by the introduced phosphorus and chlorine.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.196-205
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• 2020

The purpose of this study was to investigate a method for improving the physical and mechanical properties of laminated board made from oil palm trunk (OPT). The effects of pretreating the lamina with heat-pressure and altering the lamina composition of the laminated board were investigated. The outer third of OPT in cross-section had high-density wood, while the underlying third had low to medium density. The hot press was applied to pretreat the lamina that had low to medium density. The lamina were 1.5 cm in thickness, 5 cm in width, and 65 cm in length. The hot press was applied at 2.94 MPa or 4.41 MPa at 150 ℃ for 60 minutes, and the target thickness of the lamina was 1 cm. The three layers of the laminated board samples were bonded with isocyanate adhesive at a glue spread of 300 g/㎡ and cold pressed at 0.98 MPa for 3 h. The laminated board samples were tested according to Japanese Agricultural Standard (JAS) 234-2003. The results showed that the densification of the inner lamina did not significantly affect the physical-mechanical properties of the laminated board produced. However, the laminated board made with high-density laminas for the outer layers fulfilled the JAS 234-2003 standard for the modulus of elasticity and the modulus of rupture.

• Analytical Science and Technology
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• v.6 no.5
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• pp.435-442
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• 1993

Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.

• Analytical Science and Technology
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• v.7 no.2
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• pp.205-211
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• 1994

Acetic acid and succinic acid bonded polyamine-polyurea(CPPI and SAPPI) resins were synthesized from the reaction of polyethylenimine-polymethylenepolyphenylene isocyanate(PPI) resin as matrix polymer and chloroacetic acid and chlorosuccinic acid respectively. These resins were confirmed with infrared spectrometry and elemental analysis. The adsorption characteristics of the chromium(III) and dichromate(or chromate) ions on the resins were studied by measuring distribution coefficients($K_d$) with changing pH of the solution. It was thought that these ions were adsorbed by ion exchange mechanism. Chromium(III) and dichromate ion could be separated with stepwise elution method by changing pH of the eluent using SAPPI resin packed column($0.6cm(i.\;d.){\times}10cm(L.)$). Also, dichromate ion could be preconecntrated with CPPI resin column by a concentration factor of 50.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.1079-1084
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• 1998

Reaction kinetics between 4,4'-dihexyl methane diisocyanate($H_{12}MDI$) and n-hexanol in toluene with dibutyltin dilaurate(DBTDL) as catalyst was studied by experimental measurements and mathematical modeling. Experiments were carried out at various temperatures, catalyst concentrations and [NCO]/[OH] ratios, and the reaction kinetics were described by two second-order reactions, the one between NCO and OH leading to urethane and the other between urethane and NCO leading to allophanate. The rate constants were estimated by the Runge-Kutta 4th-order method. Experiments and mathematical simulations showed a good agreement for various experimental conditions. The [allophanate]/[urethane] ratios at 90% conversion of initial NCO were estimated to be over 20% for most conditions employed in the present study, indicating that allophanate formation might significantly affect the properties of urethane polymers.

• Journal of Microbiology and Biotechnology
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• v.11 no.2
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• pp.259-265
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• 2001

Staphylococal infection still remains to be one of the most serious infections, having various complications in the clinical use of indwelling polymeric medical devices. However, there are a few promising systems showing a high antibacterial effect without causing any demage of polymer backbone under biological environments such as blood or body fluid. In order to resolve this problem, we have designed a new antibiotic releasing system via a hydrolysis mechanism. The surface of biomedical polyurethane (PU) was modified by using 1,6-diisocyanatohexane (HMDI) to immobilize the rifampicon. Also, the immobilized rifampicin was designed to be released by a selective cleavage of the unstable carbamate linkage that exists on the rifampicin-immobilized polyurethane (PHR). The immobilization of rifampicin on the surface of polyurethane was confirmed by the disappearance of the characteristics IR absorbance peak of the isocyanate (-NCO) group at $2,267\;cm^{-1}$. The PHR showed a continuous rifampicin release profile under an aqueous environment of 10 mM of PBS (phosphate-buffered saline) for ove 6 days. The rifampicin molecules, which are released from PHR under an optimal bacterial infection environment, had a higher antibacterial activity against both S. aureus and S. epidermidis than rifampicin-incorporated polyurethane (RIP). In addition, the PHR maintained a stable antibacterial effect under a blood-mimic aqueous environment such as bovine calf serum.

• Analytical Science and Technology
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• v.7 no.3
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• pp.395-402
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• 1994

Benomyl(Methyl-1-(Butyl Carbamoyl)-Benzimidazole-2-yl-Carbamate) is widely used as pre- and post-harvest pesticide. It converts into MBC(Carbendarzime:Benzimidazole-2-yl-carbamate) and butyl-isocyanate in mild condition. In this study, three analytical methods for MBC were compared in view of detectability, correctness, and sensitivity. The first and second are HPLC analytical method employing the UV detection of MBC. Our new third method was modification of PFBB(pentafluoro-benzylbromide) derivatization method with GC-ECD & MSD. The average recoveries and detection limit of MBC in the newly modified method are 95% and $0.001{\mu}g/g$ in whole bean and bean sprouts respectively. This new method prevent pesticide analysis from misdetecting in bean and bean sprouts.

• Journal of the Korean Applied Science and Technology
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• v.19 no.1
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• pp.25-32
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• 2002

Two PU flame-retardant coatings, 2,3-DBPO/N-l00 (DBPON) and 2,3-DBPO/IL (DBPOI), were prepared by curing 2,3-dibromo modified polyester (2,3-DBPO) with isocyanate curing agent Desmodur N-l00 (or Desmodur IL) at room temperature. The physical properties and flame-retardancy of the two coatings were tested and compared. As a result, the pot-life, yellowness index, lightness index difference, $60^{\circ}$ specular gloss, cross-hatch adhesion, viscosity, and accelerated weathering resistance of DBPON were better than those of DBPOI; the fineness of grind of the two coatings were the same; and the drying time, hardness, and abrasion resistance of DBPOI were better than those of DBPON. The flame retardancy of the flame-retardant coatings increased with the content of the flame retarding component, 2,3-dibromopropanoic acid (2,3-DBP); and the LOI values of the two coatings were in a range of $27{\sim}29%$ when the content of 2,3-DBP was 30wt%.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.1-8
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• 2002

Polyurethane NCO prepolymers were synthesized with the polyols such as PTMG, GP and the isocyanate such as TDI at $40^{\circ}C$ for 8.5 minutes. As average molecular weights (${\bar{M_n}}$: 1000, 2000, 3000, 4000) of PTMG, and GP were decreased from 4000 to 1000, ratio of oil gelation increased from 298%, to 440%, for Bunker B. When oil and water were emulsified, the ratio of gelation was increased approximately two times. Ratio of gelation for emulsive Bunker B was increased from 402% to 910%, for PTMG1000 and increased from 440%, W 958% for GPI1000. Ratio of oil gelation for emulsive Bunk C which has higher viscosity than Bunker B was measured w 923% for PTMG1000 made with chain extender, i.e. EG, and measured to 1098% for GP1000. The gel made from GP which has three functional group showed soft and strong characteristic, as a result, it can be removed easily from oil spilled ocean.

• Journal of the Mineralogical Society of Korea
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• v.27 no.3
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• pp.149-158
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• 2014

Consolidants were extended use for conservation of weathered stone heritage. Epoxy, acryl, isocyanate, and alkoxysilane consolidants are most commonly used products. Consolidant of 1T1G_5 wt 0.08 % that consists of T (TEOS: Tetraethyl Orthosilicate) and G (GPTMS: 3-Glycidoxy propyl trimethoxy silane) were used this study. A shore hardness values show increasing after treated with consolidant in granite. Surface brightness after treated with consolidant are changing slightly dark but turns the original color over time. Ultra-sonic velocity is increased after treated with consolidant but slightly reduced over time to remain constant. It has the advantage of being effective after treated with consolidant in granite and efficiency of consolidation increase with slow velocity before treated with consolidant.