• Macromolecular Research
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• 제10권4호
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• pp.230-235
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• 2002

Alternating polyols of oxymethylene and oxyalkylene were synthesized and used as precursors for thermoplastic poly(ether-ester) elastomers (TPEs). The polyols were synthesized by reacting diols having different methylene units with dichloromethane in the presence of a phase transfer catalyst. The number of methylene units in the alkylene oxides was varied from 3 to 6. TPEs were prepared using the polyols as soft segments and poly(butylene terephthalate) units as hard segments. The polyols and TPEs synthesized were characterized using FTIR, NMR, GPC, DSC, and polarized optical microscopy. The polyols showed a profound odd-even effect on the melting (T$_{m}$) and glass transition temperatures (T$_{g}$). Polyols with odd numbers of methylene groups in the alkylene units have higher transition temperatures than polyols with odd number of methylene groups. The tendency is still kept in TPEs, even though the T$_{g}$ of soft segment in TPEs are slightly higher than those of corresponding neat polyols. The T$_{m}$ and T$_{g}$ of soft segments are almost constant in the range of 20 to 60 wt % contents of soft segments. On the other hand, the normalized heat of fusion of hard segment decreased with increasing the content of loft segment.ent.t.ent.

• 한국응용과학기술학회지
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• 제26권4호
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• pp.422-427
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• 2009

We have investigated the effects of polyols and NaCl on the rheological behaviours of surfactant mixtures. Sodium lauryl ether sulfate (SLES), cocamidopropyl betaine (CAPB), disodium cocoamphodiacetate (DSCA), cocamide DEA (CDEA) and lauroyl/myristoyl DEA (LMDE) were used as surfactants. The polyols added into the surfactant mixture were 1,3-butylene glycol, propylene glycol, glycerin, sorbitol, dipropylene glycol, PEG 1500 and PEG 400. The addition of amphoteric surfactant to SLES aqueous solution lead to increase the height of foam and the viscosity of the system. The addition of nonionic surfactant, LMDE or CDEA to the SLES aqueous solution increased the viscosity and the effect of LMDE was better than that of CDEA. The effect of adding polyols and NaCl into the surfactant mixture aqueous solution lead to increase or decrease the viscosity of the systems depending on the concentration of NaCl and the kinds of polyols. These results can be explained through the salting in or salting out of surfactant of the systems.

• Journal of Microbiology and Biotechnology
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• 제6권1호
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• pp.60-62
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• 1996

Aureobasidium pullulans produced three kinds of extracellular polyols e.g. glycerol, mannitol, and sorbitol from either sucrose, glucose, fructose or mannose. Sorbitol was selectively produced when urea was used as a sole nitrogen source, and the amounts of sorbitol produced rapidly reached a plateau after 50 h where its maximum quantity was about 20 g/l with sucrose.

• 한국응용과학기술학회지
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• 제25권4호
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• pp.477-484
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• 2008

It is inevitable to use chemical germicidal agents like paraben, imidazolidinyl urea and phenoxyethanol to preserve the emulsions which is usually used in cosmetics. Although these chemical preservatives are good enough to reduce the microbiological contamination, they are irritative, allergenic to the skin. Several kinds of polyols are used in cosmetics as moisturizer and solvent. In this study, we evaluate the effects of polyols on anti-microbial activities, safety and resistant index. MIC(minimal inhibitory concentration) of polyols determined against 6 germs including Staphylococcus aureus. The order of MIC was PG $\cong$ DPG $\cong$ 1,3BG > HG > 1,2-PD > 1,2-HD $\cong$ 1,2-OD. The $2{\sim}3\;wt%$ of 1,2-HD(hexanediol) shows good anti-microbial effects in emulsions without allergenic response. Resistant index of 1,2-HD was less than 2 and this value was smaller than that of chemical preservatives. The mechanism of antimicrobilogical effect might be disturb the membrane of germs by investigating using electron microscope. Added to that, using this paradigm, low preservative contents, paraben-free system, and even preservative-free systems can be expected from these results.

• 공업화학
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• 제8권2호
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• pp.230-236
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• 1997

Isophorone diisocyante(IPDI), 각각 에스터와 에테르 타입의 폴리올인 poly[butyl/ethylene adipate] glycol(PBEAG), poly[oxytetramethylene] glycol(PTMG)과 잠재적 음이온기인 dimethylol propionic acid(DMPA)로부터 음이온성 폴리우레탄 분산체(PUD)를 제조하였다. 폴리올의 종류 및 조성이 PUD의 유화 입경과 건조 필름의 기계적, 열적 성질에 미치는 영향 등을 검토하였다. 혼합된 폴리올의 조성 변화 시, PTMG 함량이 증가할수록 PUD의 유화 입경은 점근적으로 증가하는 경향을 보였고, 인장 강도는 완만한 감소를 나타내다가 증가하였다. 이는 두 폴리올간의 상용성이 적기 때문에 나타나는 결과로 해석되며, 이러한 비상용성은 DSC분석을 통하여 유리전이온도(Tg) 측정으로부터 확인할 수 있었다.

• 청정기술
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• 제17권3호
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• pp.238-243
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• 2011

본 연구에서는 폴리우레탄을 위한 친환경 폴리올 합성을 위하여 피마자유 기반의 폴리올을 합성하였다. 피마자유의 2차 알콜에 다른 촉매 없이 무수말레산을 이용하여 카르복실기를 도입하고, 이를 1차 알콜로 전환하기 위하여 아미노알콜($H_2N$-R-OH) 유도체를 반응시켜 친환경 폴리올을 제조하였다. 다양한 비율의 피마자유와 무수말레산의 반응이 시험 되었으며, 전체 반응은 상대적으로 낮은 공정온도와 무촉매 반응을 기반으로 수행되었다. 긴 곁가지가 도입되어 유동성을 가지고 있는 피마자유 기반의 천연폴리올이 기존의 합성폴리올과 가장 우수한 상용성을 나타내었다.

• Elastomers and Composites
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• 제58권1호
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• pp.32-43
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• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.

• 접착 및 계면
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• 제20권2호
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• pp.61-65
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• 2019

본 연구에서는 인계 폴리올을 phenylphosphonic dichloride (PPDC), allylphosphonic dichloride (APDC)에 ethylene glycol (EG)을 반응시켜 합성하였고 분자량이 880~1,560 g/mol의 폴리올 얻었다. 이를 이용하여 polycarbonate diol (PCD)와 함께 4,4'-diphenylmethane diisocyanate (MDI)와 중합하여 인계 폴리우레탄을 얻었다. 합성한 인계 폴리우레탄의 인의 합량이 높아질수록 열분해 온도는 감소하였지만 챠 (char)의 발생과 발생양이 증가하는 것을 확인하였다. 또한 UL-94V 시험법을 통하여 APDC를 포함하는 인계 폴리우레탄 인의 함유량이 0.5 wt%이상일 때 V-0의 난연등급되는 것을 확인하였다.

• 한국응용과학기술학회지
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• 제18권3호
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• pp.241-247
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• 2001

Aqueous urethane dispersion resin begins to assume commercial importance due to increasing environmental awareness of VOC in coating industry. Moreover there have been strong industrial needs for the development of reactive-type polyurethane flame retardant coatings. In this study, chlorinated polyester polyols were synthesized by two step polycondensation reaction using mono chloroacetic acid, adipic acid, trimethylol propane, and 1,4-butanediol. In the next step polyurethane dispersion was prepared using these chlorinated polyester polyols and isophorone diisocyanate with dimethylol propionic acid(DMPA) and trimethylamine. The structure of chlorinated polyol was characterized by GPC, FT-IR and NMR. Particle size and its distribution were examined in terms of various dispersion parameters including molecular weight and composition of polyol, amount of DMPA, and NCO/OH ratio, etc. The effect of chlorinated polyols on flammability was also evaluated.

• 한국조리학회지
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• 제21권6호
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• pp.303-311
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• 2015

무설탕 원료로서 xylitol, maltitol, isomalt, erythritol 및 sorbitol을 껌의 코팅 재료로 사용하여 코팅 공정 중 제조특성과 외관을 비교하였고, 코팅 후 표면 균일성, 색택 변화, 코팅시간, 건조시간 등을 비교하였을 때 maltitol이 가장 우수하였으며, erythritol과 sorbitol은 코팅품질과 코팅시간이 길어지는 등의 생산성과 품질면에서 껌의 코팅 소재로는 부적합하였다. 이에 maltitol, xylitol 및 isomalt로 코팅한 껌을 고온 저장하면서 코팅층의 색택 변화를 분석한 결과, maltitol 코팅껌의 경우 $80^{\circ}C$, 1일간 저장시 ${\Delta}E$값은 2.88로 상온보관 시료와 비교하여 색상의 변화가 비교적 작았으나, xylitol과 isomalt 코팅껌은 색상의 변화가 크게 나타났다. 또한, maltitol 코팅껌을 polypropylene 포장재에 넣고 저장 중 색택의 변화를 관찰한 결과, $40^{\circ}C$이하에서는 색택의 변화가 적었으며, $60^{\circ}C$에서도 30일간 저장시 색차는 3 이하로 나타나 유통과정 상 품질의 변화가 적을 것으로 판단되었다. 그러나 본 실험은 색상변화로만 저장 중 변화를 평가하였던 바, 향후 당알코올류를 코팅제로 사용한 코팅껌의 저장 중 품질에 대한 추가적인 연구가 진행되어야 할 것이다.