• Journal of the Korean Society of Safety
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• v.23 no.3
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• pp.79-86
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• 2008

In the manufacturing industries using HDI(hexamethylene diisocyanate) product hardeners, exposure to HDI is common to spray painters in terms of inhalation and dermal or ocular contact. Due to a lack of information for spray painters in automobile and furniture industries, a questionnaire survey was conducted for the prevalence of adverse health symptoms(33 spray painters and an unexposed group n = 91) to assess the importance of personal controls. Despite the small sample size, common health symptoms were reported, such as skin symptoms(dry cracked skin-61% and dermatitis/skin irritation-33%) and respiratory symptoms(phlegm-49%, asthma-21%). In addition, other adverse health symptoms were reported, such as skin rash(12%), cough(39%), shortness of breath with wheezing(30%), chest tightness and difficulty in breathing(30%). No significant eye symptoms were reported. It was founded that the adverse health symptoms reported in this study were related to poor personal work practices and inappropriate PPE use. Therefore, appropriate personal controls like PPE use, work practices, regular training and education are suggested to minimize the risk of health symptoms. In addition, medical examination will also be suggested for individual health effects.

• Polymer(Korea)
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• v.29 no.2
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• pp.177-182
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• 2005

Montmorillonite (MMT) modified with siloxane diamine was reacted with a reactant obtained from 4,4'-diphenyl methane diisocyanate (MDI) and polyester type polyol, $Nippollan4010(\bar{M}_n2000)$. Finally, polyurethane (PU)/MMT composites were prepared by using 1,4-butane diol as a chain extender in $25\;wt\%$ solution of N,N-dimethyl acetamide (DMAc). It was expected that these nanocomposites had superior exfoliation property to that of MMT dispersed polyurethanes produced by simple mixing due to insertion of siloxane main chain to the silicate interlayer of MMT. Extent of reaction and formation of final products were analysed by using FT-IR spectroscopy. Dispersion into the PU and intercalation of MMT were identified by applying X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile data were acquired by universal test machine (UTM). Thermal stability and variation of surface energy were characterized by thermal gravimetric analysis (TGA) method and measurement of contact angle on the synthesized composites, respectively. As the results the organo-MMT modified with siloxane diamine in the PU composites has an intercalated structure relatively well-expanded rather than a completely exfoliated structure. The tensile strengths and the moduli for the PU/organo-MMT composites were drastically enhanced in comparison to those of $PU/Na^+-MMT$ composites.

• Analytical Science and Technology
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• v.27 no.2
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• pp.100-107
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• 2014

Plastic has been widely used in modern artworks' materials due to its merits of process ability and mass production. In the country, value of plastic artifact is increasing but the field of plastic study is limited to industrial purpose. In this study, Identification methods of plastic were performed by SPME-GC/MS and pyrolysis-GC/MS using trace of samples. As a result of identification using SPME-GC/MS, aromatic compounds were identified from polyvinyl chloride. And alkane compounds were identified from polyethylene, and polypropylene. Aromatic compounds were identified from polystyrene, and diethylene glycol appeared in polyurethane based on polyester was identified from polyurethane. As a result of identification using pyrolysis- GC/MS, aliphatic alkenes compounds and phthalate(DEHP) were identified from polyvinyl chloride. Aliphatic alkenes compounds and phthalate(DIBP) were detected from polyethylene. 1-hexene, etc., were detected from polypropylene, aromatic compounds were identified from polystyrene, and methylene diphenyl diisocyanate which is polyurethane basic material was confirmed from polyurethane. This study suggested that non-destructive SPME and pyrolysis-GC/MS are useful to identify compounds particularly polystyrene and polyurethane. These two analytical methods were expected to be applied for identification of unidentified plastic artworks before conservation treatment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.482-487
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• 2016

Ultra-violet rays are very harmful to eye health care. The blocking of ultra-violet rays and a reduction of optical reflection in the visible light range, which is to increase the share of transmitted light, and avoid the formation of ghost images in imaging, are important for the applications of polymer eyeglasses lenses. In this study, the high-refractive index polymer lenses, n=1.67, were fabricated by injection-molded method with the xylene diisocyanate monomer, 2,3-bis-1-propanethiol monomer, and benzotriazol UV absorber (SEESORB 709) mixture. To reduce the reflection of the polymer lens surfaces, multi-layer anti-reflection (AR) coatings were coated for both sides of the polymer lens using an E-beam evaporation system. The optical properties of the UV blocking polymer lens were characterized using a UV-visible spectrometer. The material properties of the thin films, which were composed AR coating layers, refractive index, and surface roughness, were analyzed by ellipsometry and atomic force microscopy. As a result, the fabricated polymer lens perfectly blocked ultra-violet rays below 395 nm with a blocking rate greater than 99%.

• Elastomers and Composites
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• v.46 no.4
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• pp.343-351
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• 2011

We prepared polyurethane foam/cloisite30B/phosphates composites and characterized their rise time, density, cell morphology, and thermal properties. The composites were synthesized with polyadipatediol-cloisite30B composite (f=2.0), polyether-polyol (f=4.6), polymeric 4,4-diphenyl methane diisocyanate (f=2.5), and D-580 (phenyl polyoxyalkenyl phosphate). As a blowing agent, cyclopentane and distilled water were used at various concentrations of D-580 from 0 to 2.81 wt%. The rise times of PUF/Closite30B/Phosphate composites blown with distilled water were faster than those blown with cyclopentane by 30%. The composites blown with cyclopentane had spherical-shape cells and the cell diameter was decreased with increasing D-580 wt%. While $T_g$ of the composites blown with cyclopentane linearly decreased with increasing the D-580 content, the $T_g$ of the composites blown with distilled water increased with the D-580 content. All PUF/Closite30B/Phosphate composites began to decompose from $250^{\circ}C$. The composites blown with cyclopentane showed the second thermal decomposition at temperatures higher than $500^{\circ}C$. The thermal stability of all composites increased with the D-580 content. The effect of D-580 on the thermal stability of the composites was measured higher at the composites blown with distilled water.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.13 no.3_4
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• pp.107-112
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• 2007

The effect of microwave heat to retort pouches and microwavable packages was examined. 186 products were collected, but packages were consisted of five package materials such as PET, Aluminum foil, Nylon, EVOH, and polypropylene. The results showed that all packages did not exceed the limits of current packaging regulation on consumption weight of $KMnO_4$, TDI(Toluene diisocyanate), and Caprolactam. Safety control on heat resistant packages considered satisfactory, but investigation on new substances should be continued for preventing any possible migration problems of packaged foods.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.627-638
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• 1992

PPG and BPA-type polyurethane prepolymers(NCO terminated) were obtained from bisphenol A and four types of PPG, having different molecular weight and numbers of functional groups. PPG and BPA-type polyurethane dimethacrylates were synthesized by reacting PPG and BPA-type polurethane prepolymer with 2-HEMA respectively. PPG-type polyurethane dimethacrylates were formulated with initiator(CHP), inhibitor(hydroquinone) and reactive diluent(TEGDMA). The effect of formulation on the torque changes was studied. Four kinds of PPG-type polyurethane dimethacrylates, having different molecular weight and numbers of functional group, were formulated with the same amount of CHP, TEGDMA and hydroquinone. The effects of the molecular weight of PPG-type polyurethane dimethacrylate and functional group numbers of PPG-type polyurethane dimethacrylates on the torque were investigated. These results showed that the torque of PPG-type polyurethane dimethacrylates, having same numbers of functional group, increased with decreasing molecular weight of dimethacrylates and torque of PPG-type polyurethane dimethacrylate, having similar molecular weight, was increased with increasing the number of fuctional group. The glass-transition temperature(Tg) of gels obtained by thermosetting cure for the four kinds of PPG-type polyurethane dimethacrylates were measured by DSC and molecular weights between cross-links(Mc) were calculated from Tg changes.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.605-613
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• 1992

NCO-terminated prepolymers were synthesized by reacting carbonate-type polyol(PTMCG)($M_w=1,000$ and 2,000) with MDI and N-methyldiethanolamine, as a chain extender. Carbonate-type polyurethane containg zwitterionic group was prepared by reacting the prepolymer with 1,3-propane sultone. From the IR and NMR spectra of model reactions, it was known that the ionization occurred under the same condition. The structure of zwitterionic carbonate-type polyurethane(ZPU) therefore could be confirmed from the model reactions. Glass transition temperature(Tg) ranged between $-15{\sim}-30^{\circ}C$ from the thermal data. Tg was between $-15{\sim}-18^{\circ}C$ for a series of ZPU10 samples and between $-25{\sim}-26^{\circ}C$ for a series of ZPU20 polymers. Tensile strength increased with mole ratio of ionic content. On the contrary, elongation was rather dropped with mole ratio of ionic content. ZPU10-30 having better tensile strength and less elongation was selected as a membrane for the concentration of ethanol aqueous solution through pervaporation. To obtain the better selectivity, it was crosslinked with HMDI. In the swelling test, it showed the higher swelling degree at around 50wt% ethanol concentration due to the plastization effect of ethanol. To optimize the separation capacity, two operating factors-feed concentration and temperature-were considered. The overall separation capacity was as follows : separation factor, 2~83.2 ; the flux, $25.4{\sim}58.8g/m^2hr$.

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.913-916
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• 1999

Fluorine modified diisocyanate(FMD) was synthesized from tris(6-isocyanatohexyl)isocyanurate(TIHI) and N-ethyl-N-2-hydroxyethyl-perfluorooctanesulfonamide(HFA). Fluorine modified polyurethane(FMPU) was also synthesized from FMD and poly(tetramethylene) glycol(PTMG). Modified polyurethanes were made by blending FMPU into the polyester type base polyurethane(BPU). Surface and thermal properties of the blended BPU film was measured by contact angle measurement and DSC. As the amounts of FMPU was increased from 0 wt % to 1 wt %, the surface energy was dramatically decreased from 47.82 dyne/cm to 17.64 dyne/cm. But we observed little change of the contact angle with further increase in the amount of the FMPU up to 10 wt %. The data meant that the surface of the blended polyurethanes was hydrophobic due to the surface arrangement of the fluorine containing moiety in FMPU. Phase separation was induced by the incompatibility of FMPU and BPU for the samples having over 5 wt % of FMPU. The thermal analysis data of these samples showed the thermal behavior of the FMPU itself.

• Journal of the Korean Wood Science and Technology
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• v.36 no.4
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• pp.37-43
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• 2008

The research attempted to develop an eco-friendly wood adhesive based on vegetable oil (soybean oil), the renewable and sustainable natural resources, using ozonification technology for the chemical structure modification. The soybean oils (SBO) were reacted with $O_3$ at the rate of 7.13 g/h for different times, 15 minutes, 30 minutes, 60 minutes, and 120 minutes. Modified chemical structure of the ozonized SBOs were examined by Fourier transform Infrared (FT-IR) spectrum. The FT-IR spectrum of SBO had an absorbance peak at $3010cm^{-1}$ that is the characteristic peak of the unsaturated double bonds. As ozone treatment time increased, the peak of the double bond was disappeared and aldehyde or carboxyl peak appeared at $1700cm^{-1}$. The dry, wet, and cyclic boiling bond strengths of the ozonized SBO mixed with polymeric diphenylmethane-4, 4-diisocyanate (pMDI) were also investigated. In the dry shear test, all strengths met constantly the standard requirement of $7.0kgf/cm^2$ (KS F3101 2006). The bond strengths gradually increased with increasing ozone treatment time. The highest strength showed at 60 minutes ozone treatment and decreased values at 120 minutes. In the cyclic boiling shear test, 30, 60 and 120 minutes exceeded the standard requirement.