• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.669-675
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• 2009

A study has been made on the preparation of liquid resin of non-solvent and non-discoloration type for replacement of the soft PVC at room temperature. A new synthetic process was developed by structure-control design of polyurethane synthesis using pre-polymer and polyols as curing agent. The optimum recipe was made according to macro-glycols, molecular weight and reaction conditions, and the final products indicated that the mechanical properties such as tensile strength, tear strength and flexibility was very excellent than PVC products. Also, viscosity, hardness and color operations of the final products can be controlled by this system. And yellowing property by UV and NOx gas was improved from the various additive experiment.

• Elastomers and Composites
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• v.46 no.2
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• pp.158-163
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• 2011

Rigid polyurethane foam (PUF) was synthesized with different contents of aliphatic polyester polyol, aromatic polyester polyol and aliphatic polyether polyol to know change of properties under sea water. UTM(universal testing machine), DSC(differential scanning calorimetry), hardness meter and FT-IR(Fourier transform spectroscopy) were used to study the PUF`s physical properties under sea water. Compressive strength and hardness of PUF decreased with increasing the content of aromatic polyester polyol under sea water as aging. According to the results of IR spectral analysis, reduction of urethane and urea peak was found and allophanate and biuret peak increased. Although glass transition temperature of PUF increased, mechanical properties of PUF decreased under sea water, because PUF gets brittle when crosslink density increase.

• Journal of Environmental Health Sciences
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• v.28 no.2
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• pp.41-49
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• 2002

Resource recovery and recycling of materials and products including polyurethanes are viewed as a necessity in today's society. The problems of recycling polyurethane wastes has major technological, economic and ecological significance because polyurethane itself is relatively expensive and its disposal by burning is also costly. In general, the recycling methods for polyurethane could be classified as mechanical, chemical and physical. In the chemical recycling method, there ate hydrolysis, glycolysis, pyrolysis and aminolysis. This study was carried out glycolysis using new method such as sonication and catalyzed reaction. There are kinds of recycled polyols were produced by current method(glycolysis) but, this study were with catalyzed reaction and sonication as decomposers and the chemical properties were analyzed. The reaction results in the formation of polyester urethane diols and then the OH value which is determined by the quantity of diol used for the glycolysis conditions. The glycolysis rates by sonication and catalyzed reaction for the various glycols, increased as: PPG

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.54-62
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• 2012

In this experiment, the optimum concentration of polyols which were used for making transparent soaps was determined using design of experiment (DOE) method. Dipropylene glycol and 1,3 butylene glycol with short chains enhanced the transparency of soap, however, polyethylene glycol 400, glycerin and diglycerin made the soap opaque. The hardness of soap was increased as increasing the concentration of propylene glycol, diglycerin, dipropylene glycol and polyethylene glycol 400. The hardness, transparency, absorbance of water, and friction solubility could be optimized by controlling the concentration of dipropylene glycol, polyetylene glycol, sugar, and triethanolamine.

• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.317-327
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• 2009

In this study DMT(Dimethylterephthalate), NDC(Dimethyl-2, 6-Naphthalene Dicarboxylate) were used to synthesize polyester polyol which shows enhanced storage stability, improved flame retardancy, and good compressive strength. If DMT and NDC react respectively with DEG(Diethylene Glycol) which is kind of linear diol, the obtained polyester polyols tend to crystallize easily after the reaction. In case of DMT, PA(Phthalic Anhydride) which has asymmetric structure was introduced to retard the crystallization. In case of NDC, DPG(Dipropylene Glycol) which has an methyl side chain was introduced to prevent the crystallization. It was found that to introduce DPG was much more effective method to prevent the crystallization than PA. NDC and DMT were reacted together with DPG for various compositions of NDC:DMT(8:2, 6:4, 4:6 mol ratio). The obtained NDC-DMT-DPG based polyester polyol showed improved flame retardancy, and good compressive strength with increasing the content of NDC.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.614-619
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• 1992

Two types of polyurethane(PU) ionomer dispersion having different type of soft segment, viz. Poly (tetramethylene adipate) glycol(PTAd), and polypropylene glycol(PPG) were emulsion blended. Viscosity of emulsion blend, mechanical, and surface properties of the emulsion cast films were determined as a function of blend composition. Mechanical properties showed a large scatter of data or negative deviation from the additivity rule, and this was attributed to the incompatibility of soft segments. Contact angle measurement indicated that air facing surface of emulsion cast film contained more of PPG PU, due probably to its smaller particle diameter compared to PTAd PU.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.24 no.3
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• pp.111-115
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• 1998

We investigated the stability of all-trans-retinol on the liquid crystalline O/W emulsion composed of mainly alkyl polyglycerine, alkyl polyglucose and glycerine, and compared the activity of all-trans-retinol in the various forms of liquid crystal. Under certain conditions, novel liquid crystalline gel was formed around oil droplets, and layers of this liquid crystalline gel were very wide and rigid. (SWLC; Super Wide Liquid Crystal) SWLC was very helpful to stabilize retinol in O/W emulsion. After storage at 45 C for 4 weeks, all-trans-retinol in O/W emulsion composed of SWLC retained above 85% of the activity upon HPLC analysis, whereas those within no liquid crystalline emulsion gave 47% and normal liquid crystalline emulsion composed of fatty alcohols gave 40 60%. Retinol in oil phase is nealy insoluble in pure water, but in cosmetic emulsion systems can be slightly solubilized into water because emulsifiers and polyols in emulsion systems function as solubilizers. In this case, water in outer phase acts as a media for oxygen transporation$.$and thus destabilizes retinol. As a result, retinol in O/W emulsion has a tendency to become unstable. SWLC surrounding oil droplet which contains retinol is wide and rigid, therefore reduces contact between inner phase and outer phase To make SWLC, properties of emulsifiers are very important phase transition temperature should be high, and the structure of surfactants should be bulky, and their ratio should be suitable to make rigid and wide liquid crystalline gel layer in order to reduce contact between retinol in inner phase and water in outer phase.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.25 no.6
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• pp.510-518
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• 2022

Purpose: Recently, great interest has been focused on dietary fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) for the treatment of functional abdominal pain (FAP). Several meta-analyses, including those on the adult population, have been published, potentiating its role. However, pediatric studies are scarce. We aimed to evaluate the effect of a low-FODMAP diet on the severity of FAP in children. Methods: This clinical trial included 50 patients aged 3-18 years with irritable bowel syndrome and FAP that were not otherwise specified. The patients were instructed to receive a low FODMAP diet guided by a dietitian. The primary outcome was the percentage of responders after 2 months of dietary intervention compared with baseline. Other outcomes included changes in stool consistency and quality of life (QoL) scores using the KIDSCREEN-10 questionnaire, and weight-for-age z-scores. Results: After the dietary intervention, 74% of patients showed more than 30% lower pain intensity, as examined using the Wong-Baker Faces pain rating scale. Their QoL significantly improved, and patients have gained weight. Conclusion: A low FODMAP diet can improve pain intensity and QoL among children with functional abdominal pain, with no detrimental effects on body weight.

• Clean Technology
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• v.21 no.3
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• pp.171-177
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• 2015

A life cycle assessment (LCA) methodology was employed to evaluate environmental impact of recycled polyol from polyurethane in an R&D stage and to suggest future direction for improvement of environmental performance of the recycling technology. The comparison result shows between recycled polyol in the developing stage and in the anticipated mass production with virgin polyol production that environmental impact of recycled polyol of the developing stage and the anticipated mass production level correspond to 93%, 60% of that of virgin polyol, respectively. The LCA result identifies improvement areas of reducing environmental impact in recycling polyols, that is, use of alkylene oxide and steam. In the future research, this must be taken into consideration for better performance of recycling technology.

• KSBB Journal
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• v.11 no.3
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• pp.374-379
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• 1996

The production of extracellular mannitot by an efficient mannitol-producing bacterium, Lactobacillus sp. KY-107 was studied in shake flask culture using the modified MRS medium. Maximum mannitol production was obtained with fructose as the sole carbon source. Within 95 hours of incubation, a final concentration of 70g/L of mannitol from 100g/L fructose was obtained with an indicated yield of 86% based on fructose consumed. However, higher concentrations of fructose could not effectively be transformed to mannitol due to a lack of osmotolerance. The strain produced no other polyols such as glycerol and sorbitol as by-products. Yeast extract was best nitrogen source and high levels of inorganic phosphate up to 10g/L did not show any detrimental effect for mannitol formation. Manganese ion played important role in both cell growth and mannitol production. The optimum culture temperature and initial pH were $35^{\circ}C$ and 6-8, respectively.