• International Journal of Safety
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• v.1 no.1
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• pp.47-51
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• 2002

This study was performed by measuring the minimum ignition temperature of polyurethane form recovered from the recycling process of the end-of-life home appliances. The critical ignition temperature of polyurethane form was lower as the size of the sample vessel was increased, and that of polyurethane form using cyclopentane as the forming agent was relatively lower than the polyurethane form using CFC and the combustion of cyclopentane-polyurethane form occurred fiercely. It is considered that the recycling process of end-of-life home appliances using cyclopentane-polyurethane form as the insulator would require a special fire and dust explosion prevention measures since there exists a high potential hazard of fire and dust explosion during crushing and storage processes.

• Macromolecular Research
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• v.9 no.6
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• pp.332-338
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• 2001

Waterborne polyurethane as a new polymer electrolyte was synthesized by using relatively hydrophilic polyols. The morphology of polyurethane was changed as it was dispersed in water. In contrast to polyurethane ionomer, waterborne polyurethane did not form an ionic cluster but produced a binary system composed of hydrophilic and hydrophobic groups. In the colloidal system, the former and the latter existed at outward and inward, respectively. Waterborne polyurethane was prepared from poly(ethylene glycol) (PEG) /poly(propylene glycol) (PPG) copolymer, 4,4'-diphenylmethane diisocyanate(MDI), ethylene diamine as a chain extender, and three ionization agents, 1,3-propane sultone, sodium hydride and lithium hydroxide. PEG/PPG copolymer was used for suppressing the crystallinity of PEG and N-H bond was ionized for increasing the electrochemical stability of polyurethane. Low molecular weight poly(ethylene glycol) and poly(ethylene glycol dimethyl ether) (PEGDME) were used as plasticizers. DSC, FT-IR and $^1$H-NMR of the waterborne polyurethane were measured. Also, the ionic conductivity of solid polymer electrolytes based on waterborne polyurethane and various concentrations of low molecular weight poly(ethylene glycol) or PEGDME were measured by AC impedance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.356-362
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• 2016

Light-weight concrete uses forming agents for reducing weight and high heat insulation property. However, the forming agents make problems of decreased volume and compressive strength of the concrete. This research aims to having weight-reduction and securing heat insulation property using recycled wasted form polyurethane without any forming agents. A small quantity of admixture used for constructability and avoiding material segregation. We picked admixtures from two different companies which shows evenly dispersed of wasted form polyurethane. This research conducts a study on the effect of mixing ratio of admixture on the light-weight concrete used wasted form polyurethane. As a result of the test, increased mixing ratio of the admixtures results reduced fluidity of concrete. On the other hand, percentage of moisture content and compressive strength are increased slightly. Combustibility performance and sound insulation performance are also secured, as well.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.215-224
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• 1998

This paper is fundamental study to develope the extracorporeal liver support system for patient with fulminant hepatic failure(FHF) or being expected for orthotopic liver transplantation. The polyurethane foam, which is composed of the density of 33kg/m3, the average pore diameter of 500${\mu}{\textrm}{m}$, the closed window of 60-70%, was manufactured with the prepolymer of 15% NCO-, Hepatocytes were inoculated to form spheroids in polyurethane foam. The time of spheroid formation in BSA(Bovine Serum Albumin) coated polyurethane foam was shorter than that in raw polyurethane foam. To verify the function of hepatocyte spheroids, we measured ammonia removal rate, urea and albumin secretion rate. Polyurethane foam was suitable for culture of hepatocyte spheroids. And culture of hepatocyte spheroids in polyurethane foam has high possibility in using as an extracorporeal liver support system.

• Textile Coloration and Finishing
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• v.27 no.2
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• pp.126-131
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• 2015

Silica-polyurethane hybrid breathable films were prepared and their breathabilities were assessed. Appropriately aggregated silica was prepared through sol-gel reaction of water glass and its particle size ranged 360~500nm. The polyurethane dispersion was prepared by the reaction of isophorone diisocyanate(IPDI) as diisocyanate and polytetramethylene glycol(PTMG) and dimethylol propionic acid(DMPA) as polyol, particle size ranging 30~120nm. The reaction between isocyanate and hydroxyl group to form urethane bonding was checked by the intensity of the stretch peak of isocyanate at $2270cm^{-1}$ in the FT-IR. The silica was incorporated into polyurethane dispersion and casted into film. It was shown that the incorporated silica(1~5wt.%) increased water vapour permeability of the films by 30~100%, and decreased the hydrostatic pressure by 10~40%. From the results, it could be concluded that the appropriate hybridization of silica can increase the breathability of polyurethane dispersion film, while minimizing the loss of hydrostatic pressure.

• Elastomers and Composites
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• v.35 no.3
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• pp.227-235
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• 2000

This study focused on the recycling technology and application of waste polyurethane scrap($5{\sim}7mm$) and waste urethane form from the footware scrap. Firstly we suggest the waste polyurethane can be used as a component of medium for hydroponic rose culture. Secondly, recycled thermoplastic polyurethane(RTPU) was produced and blended it with high impact polystyrene(HIPS). And also, in order to extend application of recycling field, the former was produced with adding the amine foaming agent to RTPU/HIPS alloy. The main purpose of this study is to diverse of the recycling of the waste polyurethane.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.1
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• pp.44-54
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• 1993

This is an experimental study to identify the performance of air-to-air rotary heat exchanger with polyurethane foam matrix. The experimental apparatus including heating AHU(Air Handling Unit), cooling AHU, sensor chamber, and heat exchanger testing unit was designed and manufactured in this study. The performance of heat exchanger with porous polyurethane foam matrix was tested with variations of the density and the thickness of matrix, regulating the wind velocity and the rotational speed of matrix. The actual heat recovery effectiveness, air leakage rate, and pressure drop of heat exchanger were measured and analyzed.

• Journal of the Korea Institute of Construction Safety
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• v.1 no.1
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• pp.7-15
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• 2018

The purpose of this study is to analyze the limits of current measures to prevent fire accidents especially in the existence of polyurethane. Suffering numerous fire accidents, preventive measures are strengthened accordingly. However, in the existence of polyurethane, current measures are insufficient since it is still impossible to completely separate inflammables form ignition sources in case of polyurethane used as insulation. In order to identify blind spots of current fire prevention measures, this study conducted analysis on the previous fire accidents and the coverage of current legislative preventive measures. In conclusion, in order to perfectly prevent polyurethane fire accidents, not only controling of working condition but also substitution of noncombustible material for polyurethane is indispensible.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.630-634
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• 2020

We developed a processing recipe to synthesize flexible polyurethane foam with a pore size of 335 ± 107 ㎛. The gelling reaction time was varied from 0 to 30 minutes and the physical properties of the foam were evaluated. The gelling reaction where the polypropylene glycol and tolylene 2,4-diisocyanate (TDI) were reacted to form urethane prepolymer, proceeded until a chemical blowing agent, deionized water, was introduced. Fourier transform infrared (FT-IR) spectra showed that the composition of the foam did not change but the foam height reached a peak value when the gelling reaction time was 10 minutes. We found that increasing the gelling time lessened the coalescence and helped the formation of cells. Lastly, the repeatability of polyurethane foam was confirmed by one-way analysis of variance (ANOVA) by synthesizing ten identical polyurethane foams under the same experimental conditions, including the gelling reaction time. Overall, the new time parameter in-between the gelling and blowing reactions will give extra stability in manufacturing identical polyurethane foams and can be applied to various polyurethane foam processes.

• Journal of Fashion Business
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• v.8 no.1
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• pp.156-163
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• 2004

The purpose of this study is to investigate the change of handle when cotton fabric is treated with chitosan-polyurethane mixed solution and crosslinked with epichlorohydrin in order to form three-dimensional crosslinks in the molecules, which in turn would improve the wash-fastness of the chitosan-treated fabrics. The application of epichlorohydrin decreased the EM(Tensile extensibility) and WT(Tensile energy) values, indicating the stiffness increased in the treated fabrics due to the 3-dimensional crosslinking. The crosslinking of the cotton fabric samples resulted in the increase in T.H.V. effectively for the use of summer dress shirt fabric.