• Microbiology and Biotechnology Letters
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• v.16 no.2
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• pp.98-104
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• 1988

A bacterial isolate FRI-33 which produces hydrophillic polysaccharide was identified and its cultural condition was investigated. FRI-33 was identified as Enterobacter agglomerans. The optimum cultural conditions for polysaccharide production were 3$0^{\circ}C$, pH 5.7, using medium composed of glucose 25 g/$\ell$, peptone 2.0 g/$\ell$, yeast extract 0.5 g/$\ell$, KH$_2$PO$_4$ 1.0g/$\ell$, MgSO$_4$.7H$_2$ O 1.0g/$\ell$, CaCO$_3$ 2.5g/$\ell$. The polysaccharide production after 72 hours was 8.41 g/$\ell$. The polysaccharide was composed of galactose (1.0 mole), xylose (1.5 mole), gluconodeltalactone (1.9 mole) and ribose (0.03 mole). The apparent viscosity of 1% polysaccharide solution was 504 mPa.s at 60 rpm and intrinsic viscosity was 45.80 d$\ell$/ g.

• Polymer(Korea)
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• v.33 no.4
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• pp.384-388
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• 2009

The rheological properties of poly (acrylonitrile) (PAN) and cellulose acetate (CA) blend solutions in N,N-dimethyl formamide (DMF) were investigated in terms of temperature and blend composition. The solutions exhibited a very characteristic rheological behavior with variation of temperature. 8 wt% solution showed an increase of viscosity and a decrease of loss tangent as temperature was increased over the temperature range of 20 and $60^{\circ}C$. At $20^{\circ}C$ the physical properties of the solutions exhibited dependence on the blend composition. At 40 and $60^{\circ}C$, however, the effects of blend ratio on the physical properties notably diminished. The longer relaxation time at higher temperature indicated that the formation of physical structures resulting from intermolecular interactions was promoted with increasing temperature. The odd rheological responses were further elucidated by measuring of the physical properties of dilute solutions. The intrinsic viscosity of the solutions suggested that the coiled chain dimension was reduced with increasing temperature.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.383-388
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• 1985

Soy protein isolate was acylated with succinic anhydride and acetic anhydride. The functional properties are markedly improved by acylation of the $\varepsilon$-amino groups. Acylation of the available amino groups shifted the isoelectric point from 4.5 to 4.0 and enhanced the solubility between pH 4.0-6.0. In the 0.03M-$CaCl_2$ solution the solubility of the modified soy protein is much larger than that of the unmodified protein above the isoelectric point. The emulsion properties and foaming properties also improved by the modification and the effects of pH on the properties paralleled its effect on protein solubility. The changes of reduced viscosity with concentration followed Huggin's equation and by modification the intrinsic viscosity of the soy protein increased and the interaction coefficient decreased.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.115-122
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• 1993

Poly(3-hydroxybutyrate)(P(3HB)) accumulation under nutrient-rich condition with various amounts of $(NH_4)_2 SO_4$ was systematically investigated. The results of the electron-microscopy and the solvent extraction showed that the P(3HB) accumulation is unavoidable even under nutrient-rich condition. This indicates that in a two-step culture of Alcaligenes eutrophus H16, the researches should be careful in interpreting the data of polyhydroxyalkanoates(PHAs) accumulation in terms of the carbon-source fed in the second step because the two-step culture product contains the P(3HB) produced under nutrient-rich condition. The polyester production capability in a two-step batch culture of A. eutrophus H16(ATCC 17699) was also investigated using various saccharides and their derivatives such as glucose, fructose, gluconic acid, glucaric acid, sorbitol, lactose, galactose, and mannose. The polyesters synthesized were characterized by 500 MHz$^{1}H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry(DSC). 500 MHz $^{1}H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% of 3HV. Another finding is that the glucose utilization can be increased by changing the autoclaving procedure of the substrate to enhance the P(3HB) production yield up to 46 wt% of P(3HB) in dry cells.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.237-242
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• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.54-54
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• 2011

방사 공정 최적화를 위해 칩(chip)건조를 실시하여 칩의 수분을 모두 제거한 후 실험을 진행하게 된다. 칩은 그 자체가 공정수분율(0.4%) 또는 그 이상의 수분을 함유하고 있으므로 건조하지 않고 방사하면 현저히 가수분해가 일어난다. 가수분해가 일어난다면 PET 분자량도 저하되어 고분자의 성질을 잃게 되어 방사된 섬유의 물리 화학적 성질에 중요한 영향을 받게 된다. 그러므로 가수분해를 방지하기 위하여 칩내 수분을 제거하는 건조 공정을 거치는 것이다. 개발된 나노은입자을 함유한 Ag/PET 마스터배치의 제사성 및 가연성 평가을 위한 파일럿연구를 행했다. 본 연구에서 사용한 은나노 M/B 칩(chip)의 경우 일반적으로 사용하는 PET 칩에 비하여 낮은 고유점도를 가지므로 방사성에 칩의 수분이 더욱 영향을 미칠 것이라 판단되어 건조공정에 특별한 주의을 하여 진행하였다. 마스터배치의 고유점도(IV)값의 변화에 따른 제사성 및 가연성 평가를 관찰하였다. #3 M/B 칩의 제사성이 #1 M/B 칩 대비 공정성이 개선되어 두 품종 모두 비출사가 발생하지 않았으며, M/B 제조시 분산제 유무에 따른 방사공정성의 차이는 없는 것으로 보인다. 따라서 #1 M/B 대비 공정성이 개선된 점은 M/B의 IV개선에 기인하는 것으로 판단되었다.

• Microbiology and Biotechnology Letters
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• v.17 no.5
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• pp.421-428
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• 1989

A soil bacterium synthesizing an extremely viscous biopolymer was isolated and identified as Pseudomonas delafieldii. The optimal pH and temperature for the growth were 6.5 and 3$0^{\circ}C$, respectively. Maximum specific growth rate was 0.24 h$^{-1}$. The specific polysaccharide productivity, growth yield and product yield were 6.25 mg/g-cell/h, 54.5% and 38.39%, respectively. The polysaccharide was presumed to be $\beta$-glucan containing glucose and gluconolactone (1.9：1.0 in molar ratio) and 1.35 % acetyl group, Element analysis showed that it contained carbon (31.85%) and hydrogen (5.15%). The weight average molecular weight by GPC was 5.64$\times$10$^7$. The intrinsic viscosity was 42.84 dl/g.

• Journal of Pharmaceutical Investigation
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• v.29 no.1
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• pp.21-27
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• 1999

Semi-solid poly(ortho esters) (POE) were prepared to provide bioerodible carriers for sustained drug delivery systems of naloxone (NLX) in the treatment of narcotic addiction. As the POE have viscous behavior at room temperature, a significant advantage of this polymer is that it can be injected without any surgical intervention. The POE was synthesized by a transesterification reaction between 1,2,6-hexanetriol and trimethyl orthoacetate, and the structure of the polymer was confirmed by IR. The in vitro release of the drug from POE was studied. The release rate of NLX decreased with increasing intrinsic viscosities of the polymer. In vivo biocompatibility studies were carried out in rats with NLX loaded POE. Histopathological analysis showed that NLX implants are well-tolerated by rats when used subcutaneously. Pharmacokinetic studies of POE-NLX implants of two different viscosities were carried out in rabbits. In all cases, plasma concentrations of NLX were maintained over 1 ng/ml for at least 168 hours, but initial burst effect was observed. Mean residence time(MRT) was found to depend on the viscosity of the polymer.

• Polymer(Korea)
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• v.34 no.1
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• pp.58-62
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• 2010

The acrylic monomers were graft-polymerized to starch as matrix polymer by emulsion polymerization. Viscosity and particle size of the emulsion were increased with starch contents due to interaction with water and particle swelling toward the water phase by hydroxy group of starch. Chemical stability of the emulsion was also increased with enhancement of starch, but water and alkali resistance were reduced with increasing starch contents because of the increasement of hyrophilicity. Opacity of the starch-acrylic emulsion compound containing calcium carbonate was decreased with contents of starch by its intrinsic color. The film of starch-acrylic polymer showed more clear appearance with increasing starch contents owing to enhancement of amorphous state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.284-287
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• 2001

Multi-pole anisotropic Sr-ferrite sintered magnets has been studied by powder injection molding under applied magnetic field. The orientation of anisotropic Sr-ferrite powders higher than 80% during injection molding is achieved at the following conditions; apparent viscosity lower then 2500 poise in 1000 $sec^{-1}$ shear rate and applied magnetic field higher then 4 kOe. For the high fluidity and strength of injection molded compact, and the effective binder removal without defects during solvent extraction and thermal debinding, the optimum multi-binder composition is paraffin wax(PW)/carnauba wax(CW)/HDPE = 50/25/25 wt%. The rate of binder removal is proportional to the mean particle size of Sr-ferrite powders whereas it is inversely proportional to the content of Sr-ferrite powders and the sample thickness. The high magnetic properties of Sr-ferrite sintered magnets are; 3.8 kG of remanent flux density, 3.4 kOe of intrinsic coercivity, and 1.2 kG of surface flux density (l-mm-thick) in the direction of applied magnetic field.