• Journal of Adhesion and Interface
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• v.22 no.1
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• pp.8-15
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• 2021

In this study, a polyol was prepared using Jeffamine D-400 as a propylene glycol-based diamine to impart flexibility to the urethane-modified epoxy, and a urethane-modified epoxy was synthesized using the polyol. Urethane-modified epoxy synthesized with existing Bisphenol A diglycidyl ether (BADGE) epoxy, a curing agent, and a curing accelerator are mixed to prepare an epoxy adhesive, and shear strength is measured by measuring adhesion strength. As a result, shear strength and shear elongation tended to increase. These results are due to the high crosslinking density. It is believed that it can be applied to structural adhesives that are restricted in use.

• Korean Journal of Materials Research
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• v.14 no.3
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• pp.224-228
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• 2004

Respectively the powder made of ZnO added $SnO_2$ was prepared by coprecipitation method and the thick film gas sensor was fabricated by screen-printing technique, The morphology and phase of the powder and film was investigated by SEM and XRD. The specific area of the particle was linearly increased with ZnO contents. Target gas was di(propylene glycol) methylether ($CH_3$($OC_3$$H_{6}$ )$_2$OH, DPGME), which is simulant gas of blister gas. The gas sensing characteristics for DPGME were examined with flow type measurement system and the concentrations of target gas were controlled from 500 ppb to 1500 ppb. ZnO (2 wt%) added $SnO_2$ showed maximum sensitivity to DPGME at $300^{\circ}C$.

• Macromolecular Research
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• v.17 no.8
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• pp.591-596
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• 2009

To trace the plasticizing effects of propylene glycol (PG) on poly(vinyl alcohol) (PVA), the rheological properties of PVA solutions in dimethyl sulfoxide (DMSO) and the physical properties of PVA films were discussed in terms of PG content. Both properties were closely related to the hydrogen bond breaking effects of PG The 6 and 12 wt% PVA solutions containing PG exhibited Bingham behavior, which was more noticeable at lower plasticizer content and higher polymer concentration. The 6 wt% PVA solutions containing more than 30 wt% PG showed a sudden decrease of viscosity over the frequency range of 0.08 and 0.2 rad/s. However, the 12 wt% PYA solutions showed no viscosity reduction even at a PG content up to 40 wt%. The glass transition temperature of the PVA/PG films was almost linearly decreased with increasing PG content but an abrupt reduction was observed at a plasticizer content 30 wt%, suggesting that the hydrogen bond breaking effects of PG on PVA became dominant between 20 and 30 wt%. This effect was further supported by the similar tendency of the tensile properties.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.408-416
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• 2021

In the ultrasonic dispersion, in order to avoid direct contact of the radiation surface of ultrasonic transducers with a liquid sample, the liquid sample is separated by a glass container and it receives ultrasonic energy through an acoustic medium. The transmission efficiency of the ultrasonic energy in the multi-layered ultrasonic system is an important factor. In this study, we suggested a method that can improve the ultrasonic energy transfer efficiency by using a propylene glycol solution as a liquid matching layer in the multi-layered acoustic system. In this method, a propylene glycol solution was filled between the Langevin-type ultrasonic transducer and the luminol solution and the sonoluminescence phenomena in the luminol solution, which is caused by nonlinear effect of high power ultrasound radiated from the transducer, was examined by using a Photo Multiplier Tube (PMT). The transmission efficiency depending on the concentration of propylene glycol solution was observed, and we can see that as the concentration of the propylene glycol solution increased, the matching effect increased while the acoustic attenuation increased. It was confirmed that there is an optimal concentration compromised these two conflicting conditions, and the optimum concentration of the propylene glycol solution was determined experimentally.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.384-388
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• 2019

In winter season, the snow and ice accretion on the bottom of the high speed railway rolling stock and boogie part has fallen at a high speed from the ballast section (gravel section for the transmission of the rolling stock load received by sleepers and fixing sleepers), causing the gravel to be scattered, thereby damaging the railway rolling stock structures and facilities. In order to solve these problems, the gravel scattering prevention net, manual de-icing, and movable hot air machine were used, but their efficiency was low. For the more efficient de-icing than ever before, an optimum material for de-icing fluid for high speed railway rolling stock was developed by evaluating the ice melting capacity, kinematic viscosity, evaporation of the material used as a chemical de-icing fluid. Four kinds of organic acid salts (sodium formate, sodium acetate, potassium formate and potassium acetate) and two different alcohols (propylene glycol, glycerol) were used as evaluation materials. Potassium formate, potassium acetate, and propylene glycol had similar ice melting capacities in the indoor test, but the propylene glycol showed the best ice melting capacity in spraying the system simulation test. This is because the kinematic viscosity of propylene glycol was 2.989029 St, which is higher than those of other materials therefore, it could stay longer on the ice and de-icing. In addition, potassium formate and potassium acetate were difficult to be used since the crystals precipitated and adversely affected the appearance of the rolling stock. The propylene glycol is the most optimum as an de-icing fluid for the high speed railway rolling stock.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.69-74
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• 2023

As a chemical de-icing method, propylene glycol de-icing fluid is applicable for melting ice caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts in winter. By spraying propylene-glycol de-icing fluid on high-speed rail rolling stock and bogie parts in advance to minimize snow adhesion, ice-melting efficiency can be further improved. In the case of high-speed rail rolling stock, even if propylene-glycol de-icing fluid is sprayed, the anti-icing performance is poor because the fluid is almost lost on the surface of the vehicle when operating at high speed. In this study, in order to prevent freezing caused by snow and ice adhering to the lower part of high-speed rail rolling stock and bogie parts, we have investigated the properties of propylene-glycol de/anti-icing fluid containing water-repellent agents that prevent surface freezing. We tried to find the optimal component for de/anti-icing fluid for high-speed rail rolling stock by evaluating the ice melting performance, contact angle, and anti-icing performance according to the types of water-repellent agent. As a result of the evaluation, it was confirmed that an de/anti-icing fluid containing an ethoxysilane-type water repellent agent was most suitable.

• Development and Reproduction
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• v.15 no.4
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• pp.301-308
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• 2011

The tolerance evaluation for abalone Haliotis discus hannai embryos was performed using different concentrations of cryoprotective agents (CPAs): dimethyl sulfoxide, ethylene glycol and propylene glycol added to 0.2 M sucrose, respectively. 4-cell, trochophore and veliger were exposed in each CPA with different concentration for 10, 20 and 30 minutes of immersion time. Developmental rates were increased with decreased concentration of every CPA and decreased immersion time, and differed from types of CPA. Developmental rates of veliger in all the CPAs were higher than those of 4-cell and trochophore. The developmental rates and larval activity indices in ethylene glycol were comparatively higher than those in other CPAs and the effective CPA and its concentration for the cryopreservation of the abalone embryos was suggested as 2.0 M ethylene glycol with equilibration time of 30 minutes.

• Journal of Environmental Health Sciences
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• v.39 no.6
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• pp.483-491
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• 2013

Objectives: Electronic cigarettes are battery powered devices that convert a nicotine-containing liquid into an inhalable vapor. The device aerosolizes nicotine so that it is readily entrained into the respiratory tract, from where it enters the bloodstream. Information on the safety of E-cigarettes is required. Methods: Seventeen articles on studies analyzing toxic substances in the liquid and gas phases of electronic cigarettes were reviewed. Results: Tobacco-specific nitrosamines, bis(2-ethylhexyl) phthalate, formaldehyde and acetaldehyde, known to be carcinogenic agents in humans or animals, were detected in the liquid and gas phases. In addition, diethyl phthalate, acetone, ethanol, cresol, xylene, propylene, styrene, triethylene glycol, tetraethylene glycol, pentaethylene glycol cis-3-hexen-1-ol, methyl cinnamate and undecane were identified in the liquid and gas phases of E-cigarettes. Propylene glycol, glycerin, 1-methoxy-2-propanol, 1-hydroxy-2- propanone, acetic acid, 1-menthone, 2,3-butanediol, menthol, carvone, maple lactone, benzyl alcohol, 2-methyl-2-pentanoic acid, ethyl mantel, ethyl cinnamate, myosamine, benzoic acid, 2,3-bipyridine, cotinine, hexadecanoic acid, and 1'1-oxybis-2-propanol were detected in the vapors of E-cigarettes. Conclusion: The hazardous compounds identified in the liquid and gas phases of E-cigarettes should be controlled for the lowest concentrations in the raw materials and production procedures.

• Korean Journal of Veterinary Research
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• v.60 no.3
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• pp.145-153
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• 2020

This study aimed to evaluate the effects of a bioabsorbable bone hemostatic agent comprising poly (ethylene glycol-propylene glycol) copolymers (PEG-PPG) on hemostasis and osteogenesis. Bilateral 3 mm diameter calvarial defects were created in 99 male Sprague-Dawley rats. The defects were filled with PEG-PPG or bone wax. The defects of control group were left unfilled. Virtual autopsy was performed to evaluate bioabsorption. The calvaria were subjected to x-ray microtomography (microCT) and histological examination. Bone volume fraction (BV/TV) and bone mineral density (BMD) were measured using microCT; furthermore, white blood cell count and histological examination were performed. After application of PEG-PPG and bone wax, immediate hemostasis was achieved. Autopsy revealed that PEG-PPG disappeared within 48 h at the application site; in contrast, bone wax remained until 12 weeks. The PEG-PPG and control groups showed significantly more osteogenesis than the bone wax group with respect to BV/TV and BMD at 3, 6, and 12 weeks (p < 0.05). Histology revealed that the bone wax group exhibited little bone formation with inflammation. In contrast, PEG-PPG and control groups showed significantly more qualitative osteogenesis than the bone wax group (p < 0.01). In conclusion, PEG-PPG showed immediate hemostasis and was absorbed to allow progressive osteogenesis.

• Elastomers and Composites
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• v.27 no.3
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• pp.161-173
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• 1992

A series of polyurethane block copolymers based on hydroxyterminated poly(dimethyl siloxane), poly(propylene glycol) and poly(tetramethylene glycol) soft segments of molecular weights 1,809, 2,000 and 2,000, respectively, were synthesized. The hard segments consisted of 4,4'-diphenylmethane diisocyanate and 1,4-butanediol as the chain extender. Samples with different molar ratios were prepared. We tried to synthesize poly(dimethyl siloxane)-based polyurethane(PDMS-PU) containing a hard block as major fraction and a soft block as minor fraction for preparing toughened rigid systems. After a study of the pure PDMS-PU, poly(propylene glycol)-based polyurethane(PPG-PU) and poly(tetramethylene glycol)-based polyurethane(PTMG-PU), (mixed polyol)-based block copolymers and blends between PDMS-PU, PPG-PU and PTMG-PU were prepared, and characterized by means of differential scanning calorimetry, tensile testing and scanning electron microscopy. In (mixed polyol)-based PU and in lower hard segment content blends, macro-phase separation was shown, but blends with higher hard segment contents showed significant reduction in amounts of phase separation.