• Title/Summary/Keyword: PEG

Search Result 1,398, Processing Time 0.112 seconds

Studies on the Isolation and Identification of PEG-Degradable Strains and Physical Chracteristics of PEG-Films (PEG 분해균주의 분리, 동정 및 PEG Film 상용성에 관한 연구)

  • 이제혁;이준열;전억한
    • Microbiology and Biotechnology Letters
    • /
    • v.22 no.3
    • /
    • pp.316-321
    • /
    • 1994
  • Several strains capable of degrading PEGs(Polyethylene Glycols) were isolated and investigated for their biodegradation ability of PEGs. Microorganisms screened for the biodegrada- tion studies were those grown on the PEG used as a sole carbon and energy source. It was known that the number of microorganisms decreased when grown on the high molecular weight of PEG. A biodegradation of PEG was investigated with such microorganisms in the reactor and resulted in the decrease in PEG concentration meaning that PEG was degraded in the reactor. This microorganism was identified as Flavobacterium sp. The biodegradability was found to be about 18.8% for PEG-8000 and 25.4% for PEG-10,000, respectively. For the manufacture of biodeg- radable PEG film, EMAA/PEG and EAA/PEG blending ability was investigated with IR spectrum and showed that it was possible to produce blending film.

  • PDF

Changes in the Amount of PEG Free-Flowing Back from PEG-Treated Waterlogged Archaeological Wood and the Compressive Strength According to Relative Humidity Conditions (습도조건에 따른 PEG 처리 수침고목재의 PEG 용출량 및 압축강도 변화)

  • Jo, Ah Hyeon;Lee, Kwang-Hee;Choi, Tae-Ho;Go, In Hee;Seo, Jeong-Wook
    • Journal of Conservation Science
    • /
    • v.36 no.3
    • /
    • pp.225-235
    • /
    • 2020
  • The present study aimed to monitor changes in the amount of PEG free-flowing back from PEG-treated woods and compressive strength changes with change in relative humidity from 90% to 30%. The change in the relative humidity was done 3 times. For the current study, water-logged wood (Prinus group) was used and the wooden blocks cut out of it were subjected to 3 different impregnation methods combined with different drying conditions as follows: 1) impregnating with 80% PEG#4000 followed by drying in nature (hereafter PEG80), 2) impregnating with 40% PEG#4000 and then drying in vacuum freeze drying equipment (hereafter PEG40), and 3) impregnating with 40% PEG#4000 in t-butanol, followed by drying in the vacuum freeze drying equipment (hereafter TB40). It was verified that most of the PEG was free-flowing back from the PEG-treated woods; however, a small amount of left PEG was observed on the lumen surface. The amount of PEG free-flowing back from the PEG-treated woods increased whenever the relative humidity changes from 90% to 30%. The compressive strengths of PEG80 and TB40 were increased whenever the relative humidity changed from 90% to 30%, whereas PEG40 decreased. The current study showed how to control the relative humidity to effectively manage PEG-treated waterlogged woods.

Solvent Extraction of Polyethylene Glycol by Ethanol in Powder Injection Molded Compacts (분말사출성형체에서 에탄올에 의한 폴리에틸렌글리콜의 용매추출)

  • 조태식
    • Polymer(Korea)
    • /
    • v.25 no.5
    • /
    • pp.665-670
    • /
    • 2001
  • The solvent extraction of polyethylene glycol (PEG) by ethanol has been studied for the powder injection molded compacts of Sr-ferrite/PEG/carnauba wax/HDPE. The extraction rate of PEG is sensitively proportional to the solvent temperature whereas it is inversely proportional to the contents of PEG, the molecular weight of PEG. and the specimen thickness. The high extraction rate of PEG is achieved under the following conditions: solvent temperature of $70^{\circ}C$, PEG contents of 30%, and PEG molecular weight of 400 g/mol. In the early stage of solvent extraction, the non-linear relationship between the extraction rate and the square root of the extraction time indicates that the extraction of PEG does not follow the Fickian behavior. At extraction times longer than 180 min. however, the extraction of PEG follows the Fickian behavior. The extraction fate of PEG by ethanol is about$1.0{ imes}10^{-6}g/cm^2sec$ enough for common applications.

  • PDF

Measuring PEG Retentions and EMCs of PEG Impregnated Softwood Specimens after Heat-treatment (PEG 주입 침엽수 시편의 열처리 후 PEG 잔류량과 평형함수율 측정)

  • Hong, Seung-Hyun;Kim, Chung-Ho;Lim, Ho-Mook;Kang, Ho-Yang
    • Journal of the Korean Wood Science and Technology
    • /
    • v.41 no.3
    • /
    • pp.173-180
    • /
    • 2013
  • This study was carried to provide basic data for the research of the effect of PEG impregnation on preventing wood from cracking during heat treatment. Three popular softwood species were selected for investigating the PEG penetration rate and retention depending on PEG molecular weight, PEG retention after heat treatment and their EMCs. The average retentions of PEG400 were reversely proportional to the basic densities of three species and those of the other PEGs showed similar behaviour as well. It is obvious that PEG retention decreased as PEG molecular weight increased with a species. PEG impregnation increased or decreased the moisture contents of the specimens within 2%, and increased their basic densities by 16.8% as a maximum. The Weight Percentage Losses of PEG400 during heat treatment were the largest among three PEG levels, which implied that lower molecular weight PEG leached more than the highers. There was less difference in EMC between PEG impregnated and control specimens at low RH, but their difference increased at high RH.

A Study on Crack-Prevention of Pinus Rigida during Drying by Suction Treatment of Polyetylene Grycogen (PEG흡입처리에 의한 Rigida 소나무의 건조균열방지에 관한 연구)

  • Yu, Hyo-Seon;Jeong, Se-Hui
    • Korean Journal of Materials Research
    • /
    • v.7 no.1
    • /
    • pp.15-20
    • /
    • 1997
  • 목재의 건조 균열방지를 위한 진공흡입기술의 새로운 목재처리방법에 대해 연구를 수행하였다. 목재의 건조균열 방지를 위해 사용된 ployetylene grycogen(PEG) 처리재들은 PEG-1540, PEG-2000, PEG-4000, PEG-10000이었으며, 진공펌프의 감압정도는 85kPa과 39kPa 이었다. 시험결과, 진공흡입처리에 의한 PEG액의 흡입은 방사단면에 걸쳐 고르게 이루워졌음을 확인 할 수 있었다. 또한 PEG의 분자량이 증가할수록 단위시간당 PEG의 분자량이 증가할수록 단위시간당 PEG의 흡입량과 처리전.후의 함수률의 차인$\Delta$ M.C 는 PEG-2000을 변곡점으로 하여 감소하였다. 그리고 리기다 소나무의 건조균열 방지를 위한 약제 흡입처리에 있어 최적의 PEG 분자량과 농도 그리고 감압력의 조건은 각각 PEG-2000과 30%(wt.)그리고 85kPa임을 알 수 있었다.

  • PDF

Plywood Properties by PEG Treatment Conditions on Veneer (단판(單板)의 PEG 처리조건(處理條件)에 따른 합판(合板)의 성질(性質))

  • Suh, Jin-Suk;Doh, Geum-Hyun
    • Journal of the Korean Wood Science and Technology
    • /
    • v.17 no.2
    • /
    • pp.20-25
    • /
    • 1989
  • This study was carried out in order to investigate the treatment effect of PEG soln which is a common dimensional stabilizer to green log. sawing panel etc, on bonding product including plywood widely-used in secondary processing unit. The 30% concentration of aqueous PEG soln. with molecular weight of 400, 1.000 and 4,000 were prepared respectively, and also dipping the veneer in the PEG soln. spreading the PEG soln. on veneer and mixing the PEG soln. in the adhesive were allowed. Then the ratio of PEG impregnation on veneer, the adhesive strength of plywood were epitomized as follows: The ratio of impregnation by PEG 4,000 at dipping condition was highest. while that by PEG 400 at same condition was lowest. However, the effect of PEG molecular weight on the ratio of impregnation at spreading condition did not occur. 2. The adhesive strength was great in the order of 4,000>400>1,000 in molecular weight of PEG at dipping and spreading conditions. In case of mixing the PEG soln. in the adhesive, the adhesive strength was great in the order of 400>1,000>4,000 in molecular weight of PEG. Throughout three treatment conditions, PEG 400 was relatively favourable with about 10kg/$cm^2$ dry strength. 3. The adhesive strength was great 10 the order of spreading >dipping >mixing condition. 4. Although adhesive strength with the 30% concentration of aqueous PEG soln. was decreased by 35% and over, compared to control (non-treatment) adhesive strength, all types of PEG treatment except mixing the PEG soln. in the adhesive exceeded the standard dry strength for common use panel. 7.5kg/$cm^2$. 5. In warm water-proof test, the adhesive strengths by all PEG treatment conditions were less than the standard wet strength, 7.5kg cot, and also delamination of glue line occured mostly in mixing in the PEG soln. in the adhesive condition.

  • PDF

Dimensional Stabilization of Japanese Larch by Poly(ethylene glycol) Treatment (폴리에틸렌글리콜(PEG) 처리에 의한 일본잎갈나무의 치수안정화)

  • 정재열;한규성
    • Journal of Korea Foresty Energy
    • /
    • v.20 no.2
    • /
    • pp.41-45
    • /
    • 2001
  • Japanese Larch(Larix kaempferi) was treated with aqueous solutions(30%, 40%, 50%) of polyethylene glycols(PEG, #1000, #1500, #4000, #6000) for the dimensional stabilization. The antiswelling efficiency(ASE) was measured for the evaluation of the dimensional stabilization. The weight percent gains(WPGs) of the woods treated with 40% solutions were higher than those of the others, and the highest WPG was achieved by treatment with 40% solution of PEG #1500. The ASE decreased with increasing molecular weight of PEG. ASE of woods treated with PEG #1000 and PEG #1500 were higher than those of the others.

  • PDF

Effects of PEG (Polyethylene Glycol) Concentration and Mixing Ratio of PEG/Gly (Glycerol) on the Physical Properties of Silk Fibroin Films (PEG(polyethylene glycol) 농도와 PEG/Gly(glycerol) 흔합비에 따른 견 피브로인 필름의 물성)

  • Ma, Yu-Hyun;Song, Kyung-Bin
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.35 no.1
    • /
    • pp.121-125
    • /
    • 2006
  • To study the effects of plasticizer concentration and its ratio on the physical properties of silk fibroin films, polyethylene glycol (PEG) was used at 4 different concentrations; 1, 2, 3, $4.5\%$ (w/v). Tensile strength (TS) and water vapor permeability (WVP) increased with the increase of PEG concentration, while opposite trend was observed for percent elongation of silk fibroin films. WVP of silk fibroin films increased from $2.54\;ng{\cdot}m/m^2spa$ for $1\%$ of PEG to $5.41\;ng{\cdot}m/m^2sPa$ for $4.5\%$. In addition, a mixture of PEG and glycerol (Gly) as a plasticizer was used at the ratio of 100:0, 75:25, 50:50, 25:75, and 0:100 (w/w). Percent elongation of the films was improved to $130.95\%$ when the ratio of 75:25 was used. On the contrary, WVP of silk fibroin films increased with the decrease of the ratio of PEG:Gly. Effect of the plasticizer concentration and its ratio on the color of silk fibroin films was negligible. These results suggest that mixture of PEG and Gly as a plasticizer provide more flexible than PEG alone in silk fibroin films, and the best ratio of PEG to Gly was 75:25.

Synthesis and Solution Properties of Water Soluble Polyester for Metal-Working Fluids (II) (금속가공유용 수용성 폴리에스테르의 합성 및 용액특성(II))

  • Yoon, Yoo-Jung;Kim, Young-Wun;Chung, Keun-Wo;Hwang, Do-Huak
    • Applied Chemistry for Engineering
    • /
    • v.16 no.6
    • /
    • pp.834-841
    • /
    • 2005
  • Polyethylene glycol esters (PEG-esters) were synthesized by condensation reaction of dicarboxylic acid such as adipic acid and sebacic acid and several PEGs. The PEG-esters were analyzed by FT-IR, $^1H-NMR$ and HPLC for structure analysis, and by GPC for molecular weight. Through the analysis of surface tension, critical micelle concentration (CMC), aluminum contact angle of water solution containing the PEG-ester, the synthetic PEG-esters are proven to exhibit surfactant properties. The surface tension ranged from 45 to 50 dyn/cm depended on the concentration and structures of the PEG-esters. The surface tension of PEG-esters with sebacic acid moiety and short polyoxyethylene unit resulted in lower value than that of PEG-ester with adipic acid moiety and long polyoxyethylene unit. The CMC of water solution containing 2.5 wt% PEG-ester with sebacic acid moiety estimated at $0.9{\times}10^{-5}{\sim}5.3{\times}10^{-3}mol/L$ depended on the structures of PEG-esters. The CMC of PEG-esters with long polyoxyethlene unit showed a higher value than that of PEG-esters with short polyoxyethylene unit. Meanwhile, the CMC of PEG-esters with adipic acid moiety was not distinct due to their high hydrophilic character. As the results of contact angle and cutting time aginst aluminum, the contact angle ranged from $45^{\circ}$ to $53^{\circ}$ depended on the concentration of PEG-esters. The cutting time of aluminum showed the shortest value at CMC, but the longest value above CMC. This fact indicates that the CMC of PEG-esters is a very important factor in drilling aluminum.

Safety Evaluation of Polyethylene Glycol (PEG) Compounds for Cosmetic Use

  • Jang, Hyun-Jun;Shin, Chan Young;Kim, Kyu-Bong
    • Toxicological Research
    • /
    • v.31 no.2
    • /
    • pp.105-136
    • /
    • 2015
  • Polyethylene glycols (PEGs) are products of condensed ethylene oxide and water that can have various derivatives and functions. Since many PEG types are hydrophilic, they are favorably used as penetration enhancers, especially in topical dermatological preparations. PEGs, together with their typically nonionic derivatives, are broadly utilized in cosmetic products as surfactants, emulsifiers, cleansing agents, humectants, and skin conditioners. The compounds studied in this review include PEG/PPG-17/6 copolymer, PEG-20 glyceryl triisostearate, PEG-40 hydrogenated castor oil, and PEG-60 hydrogenated castor oil. Overall, much of the data available in this review are on PEGylated oils (PEG-40 and PEG-60 hydrogenated castor oils), which were recommended as safe for use in cosmetics up to 100% concentration. Currently, PEG-20 glyceryl triisostearate and PEGylated oils are considered safe for cosmetic use according to the results of relevant studies. Additionally, PEG/PPG-17/6 copolymer should be further studied to ensure its safety as a cosmetic ingredient.