• 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.

• Applied Chemistry for Engineering
• /
• v.4 no.4
• /
• pp.715-720
• /
• 1993

Diphenylmethane (pKa=33.4), which is difficult to be oxidized in normal oxidation conditions, was oxidized to produce benzophenone at ambient temperature and atmospheric pressure by using phase transfer catalysts and solid potassium tert-butoxide as base. Quaternary salt such as benzyltriethylammonium chloride, tetrabutyl ammonium bisulfate, tetrabutylphosponium chloride, are ineffective catalysts for this reaction, but 18-crown-6 and polyethylene glycols showed catalytic activity. The conversion of diphenylmethane was increased with increasing chain length of PEG molecules when they are used as phase transfer catalysts both in equal molar and equal weight basis. The conversion of diphenylmethane was increased with the agitation speed, and aprotic solvent like DMF showed higher reaction rate compared with benzene.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.2
• /
• pp.161-170
• /
• 2001

Synthetic water-based metal-cutting fluids are increasingly popular in the metal-working industry because of its environmental friendliness. The propose of this study is to investigate the synergistic effect of combining polyethylene glycol and common fatty acid in formulating a metal-cutting fluid. The tested metals were aluminum, copper and steel, and the test was performed with a modified drilling machine. From the study, it was found that there existed some synergistic effects on the drilling efficiency of the metals to decrease of cutting time, cutting energy, torque as well as the smoothness of surface depended on the formulation ratio of the two fluids.

• Korean Journal of Microbiology
• /
• v.24 no.3
• /
• pp.329-334
• /
• 1986

The bacteria capable of utilizing polyethylene glycol(PEG) 6,000 as a sole carbon source were isolated from soil and sewage water connected to factory area. The isolate designated as EL-033 had high biodegradability on PEG 6,000, and was identified as Micrococcus sp. Micrococcus sp. EL-033 could grow on and degrade di-, tri-, tetraethylene glycols and PEGs with molecular weight up to 6,000 and very slowly stilize PEG 20,000 as sole carbon source, but not degrade ethylene glycol. The growth rate of isolate was increased in the higher molecular weight PEGs. The optical culture medium was established to be as follow: PEG 6,000, 0.2%(w/v); $K_2HPO_4$, 0.1%; $NaH_2PO_4{\cdot}12H_2O,\;0.1%\;:\;MgSO_4{\cdot}7H_2O$, 0.05%; polypeptone, 0.1% in distilled water, pH7.5. About 90% of PEG 6,000 was degraded in exponential phase of 48h culture and PEG 6,000 was completely degraded during 72h.

• Journal of Powder Materials
• /
• v.6 no.2
• /
• pp.132-138
• /
• 1999

A new binder system and debinding process for low carbon residue in the injection molding of Nd(Fe, Co)B powder are investigated. In the injection molding of magnetic materials, it is demanded to reduce carbon residue which deteriorates their magnetic properties. The binder system developed is composed of polyethylene glycols (PEGs) and polypropylene (PP). PEG was selected as a major binder is component to be extracted in a molecular state by solvent extraction in ethanol, which step would leave no residue. PP was selected as a minor binder component to be subsequently removed by thermolysis which step would leave carbon residue. The behaviors of solvent extraction with the variations of PEG molecular weight, temperature, and time were examined. The dependency of residual carbon content on thermolysis atmosphere was also studied. Opened pore channels introduced in a green body by the solvent extraction and microstructures of the sintered magnets were observed using SEM.

• Archives of Pharmacal Research
• /
• v.20 no.3
• /
• pp.269-274
• /
• 1997

Solubilities of oleanolic acid and ursolic acid in aqueous surfactant solutions, liquid polyethylene glycols (PEG), and solvents of various polarity were measured. The results showed that the solutes were slightly or moderately solubilized in the surfactant solutions and the liquid PEGS. It was also revealed that the solutes were slightly soluble in the solvent of either extreme polarity or nonpolarity, but moderately soluble in solvents of intermediate polarity of which solubility parameters are around 10. The solubility parameters of these solutes were calculated from the group contribution to be 10.2 for both of them. Of the solvents tested, tetramethylurea was exceptionally effective in solubilizing the solutes. The solutes were also moderately soluble in the aqueous cosolvents containing tetramethylurea. This suggests that the mixed systems of tetramethylurea could be employed for the solubilization in the formulation of these compounds as an aqueous system.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.20 no.4
• /
• pp.244-251
• /
• 2017

Purpose: We evaluated the efficacy and safety of combined oral and enema therapy using polyethylene glycol (PEG) 3350 with electrolyte solution for disimpaction in hospitalized children. Methods: We retrospectively studied 28 children having functional constipation who received inpatient treatment between 2008 and 2016. The amount of oral PEG 3350 electrolyte solution administered was 50-70 mL/kg/d (PEG 3350, 3-4.1 g/kg/d), and an enema solution was administered 1-2 times a day as a single dose of 15-25 mL/kg (PEG 3350, 0.975-1.625 g/kg/d). A colon transit time (CTT) test based on the Metcalf protocol was performed in some patients. Results: Administration of oral and enema doses of PEG 3350 electrolyte solution showed $2.1{\pm}0.3$ times and $2.9{\pm}0.4$ times, respectively. After disimpaction, the frequency of defecation increased from $2.2{\pm}0.3$ per week to once a day ($1.1{\pm}0.1$ per day). The number of patients who complained of abdominal pain was reduced from 15 (53.6%) to 4 (14.3%). Before hospitalization, nine patients underwent a CTT test, and 5 of 9 patients (55.6%) were classified as belonging to a group showing abnormalities. And in some patients, mild adverse effects were noted. We examined electrolytes and osmolality before and after disimpaction in 16 of 28 patients, and no abnormalities were noted. Conclusion: In terms of therapeutic efficacy and safety, combined oral and enema therapy using high-dose PEG 3350 with electrolytes is considered superior to conventional oral monotherapy or combined oral and enema therapy on an outpatient basis.

• Applied Chemistry for Engineering
• /
• v.16 no.2
• /
• pp.206-211
• /
• 2005

Mediated electrochemical oxidation (MEO) of polyethylene glycols (PEGs) of molecular weight of 1000, 4000 and 20000, was carried out on both platinum (Pt) and titanium-iridium electrodes in 8.0 M nitric acid solution containing 0.5 M Fe(II) and Co(II) ion. The electrochemical parameters such as current densities, kinds of electrode, electrolyte concentration and removal efficiency were investigated in both Fe(III)/Fe(II) and Co(III)/Co(II) redox systems. The PEGs was decomposed into carbon dioxide by MEO in Fe(III)/Fe(II) and Co(III)/Co(II) redox system during 180 min and 210 min at the current density of $0.67A/cm^2$ on the Pt electrode. Removal efficiency of PEGs by MEO was better in Co(III)/Co(II) redox system than Fe(III)/Fe(II) redox system, indicating mediated electrochemical removal efficiency was 100%.

• 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.

• Elastomers and Composites
• /
• v.49 no.2
• /
• pp.110-116
• /
• 2014

We investigated the effect of the concentration of stannous 2-ethylhexanoate catalyst on the esterification rate between adipic acid (AA) and each of two PEG oligomers, diethylene glycol (DEG) and polyethylene glycol (PEG600). The concentration of the catalyst was varied from 0.15 to 2.0 wt.%. To attach hydroxy group to each end of the poly(oxyethylene-co-adipate) synthesized from AA and the PEGs, the esterification was performed with excessive PEG oligomers ([PEG]/[AA]=2) at $170^{\circ}C$. The degree of polymerization of the poly(oxyethylene-co-adipate)diol products were three. The apparent rate constant ($k_{app}$) of the esterification between AA and DEG shows the first order dependency on the catalyst concentration ($k_{app}=0.88[C_{cat}]$), whereas the $k_{app}$ of the esterification between AA and PEG600 has a relation of $k_{app}=0.123[C_{cat}]^{0.55}$ with the catalyst concentration. It is expected that the rate of esterification between AA and DEG has a non-linear dependency on the catalyst concentration as the catalyst concentration approaches to 0.22M.