• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.77-83
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• 2006

This study was carried out to investigate the agronomical and physicochemical properties of five newly bred sugary lines in YARI (Yeongnam Agricultural Research Institute) that developed from the cross of sugary and Hwayeongbyeo, Hwasambyeo and Seomjinbyeo. Culmlength of newly bred sugary lines were longer than that of Nampyeongbyeo as $84.2{\sim}99.3cm$. However the weight of 1,000 grains and yield were lower than that of Nampyeongbyeo by two to three times. According to physicochemical properties, most of the new bred sugary lines showed low contents of amylose and mineral compare to normal varieties. And all sugary lines showed much higher amount of the sucrose and glucose contents compare to Nampyeongbyeo. Especially the sucrose content of newly bred sugary line, 55413, was 5 times higher than that of Nampyeongbyeo nevertheless, fructooligosaccharide and isomaltooligsac charide were not detected. The amylopectin constitution of sugary lines showed more chairs of DP (Degree of Polymerization)<12 but fewer chains of DP $13{\sim}24$ compare to Nampyeongbyeo. Newly bred sugary lines were lower viscosity in RVA (Rapid Viscosity Analysis).

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.302-308
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• 1997

${\beta}-Cyclodextrin\;({\beta}-CD)$ polymers were prepared using epichlorohydrin as a cross linking agent. The polymers were separated into ${\beta}-CD$ soluble polymer $({\beta}-CD\;SP)$ and ${\beta}-CD$ insoluble polymer $({\beta}-CD\;ISP)$ on a 10,000 molecular weight cut-off membrane (YM 10). Optimum separation conditions in the YM 10 were: transmembrane pressure 51.7 kPa, separation temperature $35^{\circ}C$, and volume concentration ratio 10. The flux was $0.025\;mL/cm^{2}/min$ under the optimum conditions. Gel permeation chromatography indicated that ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$ had a degree of polymerization of $2{\sim}8$ and over 10, respectively. The formation of an inclusion complex with hydrophobic compounds such as 4-dimethylaminoazobenzene, methyl red, and naringin was compared among ${\beta}-CD,\;{\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. The molar absorptivity for the two chromatic compounds was increased and the absorption peak was shifted in the presence of ${\beta}-CD$ polymers. Naringin, the principal flavonoid bitter tasting component of citrus fruit, had a low water solubility. The solubility of naringin was increased through the formation of an inclusion complex with ${\beta}-CD$ polymers. There was no significant difference in the formation of an inclusion complex between ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. Reduction of the bitter components from citrus products was shown to be possible when employing ${\beta}-CD\;SP$, while the usage of ${\beta}-CD$ monomer has been limited due to the low water solubility.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.315-322
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• 2014

Purpose: The physical and optical characteristics of hydrophilic tinted contact lens containing titanium silicon oxide nanoparticles and the basic hydrogel contact lens material containing 4-iodoaniline were examined. In this study, the utility of titanium silicon oxide nanoparticles as a UV-blocking material for ophthalmologic devices were investigated by measuring the UV transmittance of the produced polymer. Also, titanium silicon oxide nanoparticles only without the addition of 4-iodoaniline in primary contact lens materials by copolymerizing two groups were compared. Methods: For manufacturing hydrogel lens, HEMA, MA, MMA, 4-iodoaniline and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. Also, the titanium silicon oxide nanoparticles was used as additive. After polymerization the physical properties such as water content, refractive index, contact angle and spectral transmittance of produced contact lenses were measured. Results: Measurement of the physical properties of the copolymerized material showed that the water content, refractive index, UV-B transmittance and contact angle were in the range of 35.01~38.60%, 1.4350~1.4418, $34.15{\sim}57.25^{\circ}$ and 1.0~10.0%, respectively. Titanium silicon oxide nanoparticles is not used as an additive in the experimental group, the results of the measurement showed that the water content, refractive index, contan angle and UV-B transmittance of the hydrogel lens polymer was 34.00~36.80%, 1.4378~1.4420, $40.15{\sim}60.16^{\circ}$ and 1.8~25.0%, respectively. Conclusions: Also, the transmittance for UV light was reduced significantly in combinations containing titanium oxide nanoparticles.

• Elastomers and Composites
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• v.36 no.4
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• pp.225-236
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• 2001

In order to improve the properties of the copolymer and the terpolymer that was used as removal-type pressure sensitive adhesive(PSA), we synthesized quaterpolymer with the variation of the types of monomer, initiator, and solvent, and concentration, the monomer/solvent ratio, reaction temperature and time. and determined the properties of this adhesive: the viscosity, molecular weight, conversion, solid content and structure of polymer. The prepared polymer was crosslinked by changing the type of crosslinking agent and concentration, and then we investigated the characteristics or adhesive such as peel adhesion, shear adhesion, heat resistance, weathering resistance and peel adhesion to aging. The optimum performance of RA/2- EHA/MMA/2-HEMA as a PSA were obtained when benzoyl peroxide was used as an initiator with the reactant mixture consisted of 80% BA and 2-EHA, 15%, MMA, and 5% 2-HFMA. The optimum reaction temperature and time were $80^{\circ}C$ and 8 hours, respectively. For BA/2-EHA/MMA/AA, the optimum performance was obtained when the polymerization was performed at the monomer composition of 80% BA/2-EHA, 15% MMA, and 5% AA. BPO was used as initiator and the optimum reaction temperature and time were identical to those of BA/2-EHA/MMA/ 2-HEMA. Isocyanate and melamine were used to crosslink BA/2-EHA/MMA/2-HEMA and BA/2-EHA/MMA/AA, respectively. No effect on the type of cross-linking agent on the peel adhesion was observed with aging. The quarterpolymers crosslinked with melamine left residues on the counter surface after weathering resistance test, while the polymers crosslinked with isocyanate did not.

• Membrane Journal
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• v.18 no.4
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• pp.261-267
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• 2008

A graft copolymer consisting of poly(vinyl chloride) (PVC) backbone and poly(hydroxyethyl acrylate) (PHEA) side chains was synthesized via atom transfer radical polymerization (ATRP). Direct initiation of the secondary chlorines of PVC facilitates grafting of hydrophilic PHEA monomer. This graft copolymer, i.e. PVC-g-PHEA was cross-linked with sulfosuccinic acid (SA) via the esterification reaction between -OH of the graft copolymer and -COOH of SA, as confirmed by FT-IR spectroscopy. Ion exchange capacity (IEC) continuously increased to 0.87meq/g with increasing concentrations of SA, due to the increasing portion of charged groups in the membrane. However, the water uptake increased up to 20.0wt% of SA concentration above which it decreased monotonically. The membrane also exhibited a maximum proton conductivity of 0.025 S/cm at 20.0 wt% of SA concentration, which is presumably due to competitive effect between the increase of ionic sites and the crosslinking reaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.5
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• pp.738-746
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• 2011

We manufactured rice-whole soybean curd by a microbial transglutaminase (MTGase) with a mixture of hydrolyzed rice and micronized whole soybean powder (MWSP) and analyzed its rheological properties, including texture, viscoelasticity, protein cross-linking, and surface structure. A 40% rice suspension digested with a Termamyl enzyme at $85^{\circ}C$ for 20 min showed a 9.0% reducing sugar and a consistency of $1.27\;Pa{\cdot}s^n$, resulting in a great reduction in consistency. A MWSP suspension with 22% solid content was transformed into a typical tofu texture. MWSP curd fortified with 7.5% rice showed enhanced texture properties, with a hardness of 639.6 dyne/$cm^2$, and a springiness of 0.96. In a MWSP suspension (18~22% w/v) treated with 5% MTGase, viscoelasticity increased dependently with MWSP concentration, and a 22% MWSP indicated a G' value of 5.1 Pa and a G'' value of 9.0 Pa. Furthermore, soybean proteins present in the 22% MWSP curd largely disappeared or formed polymers with a high molecular weight by MTGase reaction within 30 min. MWSP (22%) fortified with 7.5% rice showed similar polymerization patterns on SDS-PAGE. The surface structure of the rice-MWSP curds was more dense and homogeneous network due to the addition of hydrolyzed rice. However, the surface structure of all rice-MWSP curds became rough and showed a non-homogeneous network after cold storage.

• Polymer(Korea)
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• v.33 no.4
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• pp.319-325
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• 2009

The solution polymerization was conducted to synthesize pressure sensitive adhesive for polarizer film using acrylic monomers. 2-Ethylhexylacrylate, butylacrylate, acrylic acid were used as acrylic monomers. The ratio was 2-ethylliexylacrylate:butylacrylate:acrylic acid=25:50:3.6 by reflecting $-40^{\circ}C$ of glass transition temperature in the pressure sensitive adhesive. When 1 wt% of coupling agent was added to the polymerized pressure sensitive adhesive, the light transmissivity was significantly increased. This result is due to the enhancement of adhesive power against liquid crystal cell by Si-O bond of coupling agents. Cross-linking agent was added by 0.5, 1.0, and 1.5 wt% with respect to the synthesized polymer. Initial tackiness decreased, while cohesion increased with increasing crosslinking agent. In the analysis of contact angle, the increase of crosslinking agents yielded the enhancement of surface energy, resulting in the decrease of contact angle. From the measurement of heat resistance, the acrylic pressure sensitive adhesive showed excellent heat resistance regardless of change in temperature and contents in crosslinking agent. In the observation of a cutting plane, the increased crosslinking agent represented a smoother and cleaner section. Comprehensively, the optimum additive amount of crosslinking agent was determined to be 1.0 wt% to monomer.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.45-53
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• 1987

The purpose of this study was to evaluate the tensile bond strength between composite resin and the human enamel. Three composite resin systems, two chemical (Clearfil Posterior, and Clearfil Posterior-3) and one light cure (Photo Clearfil-A), used with and without an intermediate resin (clearfil bonding agent), were evaluated under different amounts of load (10g, 200g and 200g for a moment) for in vitro tensile bond strength to acid-eched human enamel. Clinically intact buccal or lingual surfaces of 144 freshly extracted human permanent molars, embedded in acrylic were flattened with No #600 carborundum discs. Samples were randomly assigned to the different materials and treatments using a table of random numbers. Eight samples were thus prepared for each group(Table 2) these surfaces were etched with an acid etchant (Kurarey Co. Japan) in a mode of etching for 30 seconds, washing for 15 seconds, and drying for 30-seconds. During the polymerization of composite resin on the acid-etched enamel surfaces with and without bonding agent 10-gram, 200 gram and temporary 200 gram of load were applied. The specimens were stored in 50% relation humidity at $37^{\circ}C$ for 24 hours before testing. An universal Testing machine (Intesco model No. 2010, Tokyo, Japan) was used to apply tensile loads in the vertical directed (fig 5), and the force required for separation was recorded with a cross head speed of 0.25 mm/min and 20 kg in full scale. The results were as follow: 1. The tensile bond strength was much greater in applying a bonding agent than in not doing that. 2. The tensile bond strength of chemical cure composite resin was higher than that of light cure composite resin with applying on bonding agent on the acid-etched enamel. 3. In case of not applying a bonding agents on the acid-etching enamel, the highest tensile bond strength under 200 gram of load was measured in light cure composite resin. 4. The tensile bond strength under 200-gram of load has no relation with applying the bonding agent. 5. Under the load of 10-gram, There was significant difference in tensile bond strength as applying the bonding agent.

• Composites Research
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• v.35 no.3
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• pp.127-133
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• 2022

Polypropylene (PP) has been received great attention as a next-generation high-voltage power cable insulation material that can replace cross-linked polyethylene (XLPE). However, the PP cannot be used alone as an insulation material because of its high elastic modulus and vulnerability to impact, and thus is mainly utilized as a form of a copolymer with rubber phases included in the polymerization step. In this paper, a soft PP-based blend was prepared through melt-mixing of impact PP, polyolefin elastomer, and propylene-ethylene random copolymer. The elastic modulus and impact strength of the blend could properly be decreased or increased, respectively, by introducing elastomeric phases. Furthermore, the blends showed a high storage modulus even at a temperature of 100℃ or higher at which the XLPE loses its mechanical properties. In addition, the blend was found to be effective in suppressing the space charge compared to the pristine PP as well as XLPE.