• Journal of Applied Biological Chemistry
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• 제43권2호
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• pp.79-85
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• 2000

Biodegradable films were prepared from roasted sesame meal and rice bran. Acetic anhydride, succinic anhydride, and formaldehyde were added to the film-forming solutions, and their effects on tensile strength, percent elongation, water vapor permeability, and water solubility of the films were studied. Roasted sesame meal did not form film without acylation or addition of formaldehyde. Acylated roasted sesame films had higher tensile strength and water-solubility, and lower % elongation than rice bran films. Acylation with acetic and succinic anhydrides increased tensile strength, percent elongation, and water solubility of rice bran films, but decreased water vapor permeability. Treatment with formaldehyde increased tensile strength of roasted sesame and rice bran films and % elongation of rice bran films, while reducing water-solubility of roasted sesame and rice bran films and water vapor permeability of rice bran films.

• 접착 및 계면
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• 제25권1호
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• pp.162-168
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• 2024

The effect of maleinized polybutadiene (MPB) on the mechanical properties of epoxy resins including adhesion strength, elongation and impact peel resistance was investigated in this study, in which MPB is an anhydride-functionalized polybutadiene prepolymer. Different molecular weights (3.1K and 5.6K) of MPB were added to diglycidyl ether bisphenol-A (DEGBA), an epoxy resin, to increase its impact peel strength and elongation. At various loading percent (5, 10, 15, 20 and 25 wt%) of MPB in the epoxy resin, significant improvements of mechanical properties were observed. According to the comparative analysis results, the modified epoxy system with 15 wt% (3.1K) MPB exhibited the highest lap shear strength, about 40% higher than that of neat epoxy. The tensile strength and elongation steadily and simultaneously increased as the loading percent of MPB increased. The impact peel strengths at low (-40℃) and room (23℃) temperatures were substantially improved by MPB incorporation into epoxy resins. Reactive and flexible MPB prepolymer seems to construct strong nano-structured networks with rigid epoxy backbones without sacrificing the tensile and adhesion strengths while increasing impact resistance/toughness and elongation properties. For higher impact peel while maintaining adhesion and tensile strengths, approximately 10-15 wt% MPB loading in epoxy resin was suggested. Consequently, incorporation of functionalized MPB prepolymer into epoxy system is an easy and efficient way for improving some crucial mechanical properties of epoxy resins.

• 한국작물학회지
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• 제51권4호
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• pp.287-294
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• 2006

Germination and early elongation of rice after germination were investigated in anoxic air treatment, nitric oxide gas treatment, and six concentrations of mercuric chloride solutions to determine the effects of limited oxygen environment, nitric oxide, and inhibited water flux through cell membrane in $17^{\circ}C$. Anoxic air treatment affected germination of tested six varieties very little. However root elongation rates were severely inhibited while shoot growth was affected less. Reductions in shoot and root elongations demonstrated genotypic variations. Nitric oxide delayed the germination of rice even though it didn't affect the final percent germination. Elongations of root and shoot were inhibited in nitric oxide treatment. The inhibitor effect of nitric oxide on the shoot elongation of rice was less severe, while nitric oxide completely inhibited the root emergence of rice. Concentrations of $HgCl_2$ greater than $300{\mu}M$ dramatically reduced the rate and percentage of germination when compared to distilled water treatment. The reduced percent germination showed the greatest variation among rice varieties in $500{\mu}M$ solution of mercuric chloride. Ansanbyeo, Jinheung, and Odaebyeo were affected less by $HgCl_2$, Nonganbyeo and Sangmibyeo were intermediate, and the germination of Andabyeo was greatly reduced by $HgCl_2$. Root elongation of germinated rice seedlings was more sensitive to oxygen deficits, nitric oxide, and $HgCl_2$ treatments than germination and shoot elongation. In conclusion, poor seedling establishment of rice sown in flooded paddy soils, in which the oxygen supply to the seeds is restricted, appears to the result of limited root elongation rate.

• 한국초지조사료학회지
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• 제15권2호
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• pp.80-86
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• 1995

High salinity common in reclaimed soil can reduce germination of crop seeds and aftermath its establishment and production. The experiment was done to measure germination and radicle elongation of berseem, subterranean, white clover and Italian ryegrass as Control under different temperature and NaCl concentrations. Onehundred seeds of berseem (Trifolium ulexandrinum cv. Bigbee). suberranean (T. suhterruneum, cv. Nungarin), white clover (T. repens, cv. Regal) and Italian ryegrass (Lolium mulriflorum, cv. Terafloum) were placed in petri dishes with a sheet of filter paper replaced every two days, and then exposed to 0, 12.5, 25. 50, 100 and 200mh4 of sodium chloride in darkened growth chambers controlled with 10, 15 and $20^{\circ}C$. Percent germination and radicle elongation were measured. Beneem clover showed greatest daily percent germination among the cloven. That of subterranean clover, moreover, was higher than that of white clover till 4 days after imbibition but the reverse result was true thereafter. Although germination of Italian ryegrass was delayed with decreased at 200mM of NaCl of $20^{\circ}C$. at 200mM of under$15^{\circ}C$ , and at higher than lOOmh4 of all level of temperature, respectively. Berseem clover had greatest radicle length under the same concentration of NaCl regardless of temperature treatment while radicle elongation of subterranean and white clover was repressed over 50-100mM of NaC1. The slope of linear regression equation between concentration of NaCl and percent germination declined under all temperature treatment in order of berseem, subterranean and white clover whereas the reverse result was showed in radicle length.

• 한국염색가공학회지
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• 제1권1호
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• pp.35-46
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• 1989

Experiments described in which cotton fabrics at different stages of chemical processing were abraded to different extents on a Stoll Abrasion Tester with three different abradants, namely, a worsted fabric, flax fabric and silicon carbide paper. The four different plain-weave cotton fabrics selected were 1) desized, 2) scoured and bleached, 3) mercerized, 4) resin-treated. The surface abrasive damages of treated fabrics were observed by SAM, and load-elongation percent retentions of abraded samples were measured by Instrong Tester. The result were as follows: 1. The maximum percent retention of load-elongation with three different abradants was exhibited by the scoured and bleached fabrics and the minimum by the resin finished fabric. 2. The electron micrographs of four different cotton fabrics abraded by flax, worsted fabric abradants for 900 rubs showed a large number of criss-crossing stray fibers in fabric structure. It may be the molecular adhesion for frictional resistance to be explained. 3. The electron micrographs of four different cotton fabrics abraded by silicone carbide abradants showed the form of busing or mashing fibers in fabric structure. The above might be on the basis of the ploughing theory.

• 한국잠사곤충학회지
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• 제19권1호
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• pp.33-36
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• 1977

Graft polymerization of vinyl monomers onto silk were carried out in aqueous medium using ceric salt as an initiator, and discussed about the mechanical properties of silk. The results obtained are summarized as follows: 1. Percent grafting is greatly enhanced by the increasing of the temperature. 2. Effect of percent grafting is in the order of methyl methacrylate, and vinyl acetate. 3. Strength is decreased in the high grafted silk, and elongation is increased in the low grafted silk.

• 한국잠사곤충학회지
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• 제33권2호
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• pp.87-92
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• 1991

견사에 대한 실용적인 염축조건 구명을 위하여 3종 중성염류의 처리농도시간 및 온도조건이 처리견사의 수축율 및 물성에 미치는 영향을 검토한 결과 1. Ca(NO3)2의 처리조건, 비중 1.45, 9$0^{\circ}C$ 또는 비중 1.46, 8$0^{\circ}C$에서 견사의 수축율이 35% 내외였다. 2. CaCl2는 비중 1.33, 9$0^{\circ}C$, 5분 또는 85$^{\circ}C$ 10분의 처리조건에서 견사의 수축율이 40% 내외였다. 3. LiBr은 비중 1.38, $25^{\circ}C$ 24시간 처리에서 견사의 수축율 40% 내외였다. 4. 수축율 증가는 여러 가지 물리적 성질변화를 가져오는데 3종의 중성염류에 따라 변화율은 다소 차이가 있으나 강도의 감소가 현저히 나타나며 신도는 증가하는 추세를 나타내었다. 5. 염축견사의 팽화도는 미처리견사에 비하여 100% 이상 향상되었으나 처리견사의 강력은 미처리견사의 반 정도로 감소되었다.

• 한국포장학회지
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• 제16권2_3호
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• pp.59-65
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• 2010

Starch was modified with epichlorohydrin(ECH) to improve the miscibility with LDPE and LLDPE. Native starch or epichlorohydrin treated starch was mixed with grycerol and LDPE/LLDPE resin using a kneader and extruded using a single screw extruder to make pallets. The pallets were compression-molded at 145 into composite boards to evaluate their color, oxygen permeation, mechanical and thermal properties, and degradability under UV irradiation. Sheets with epichlorohydrin treated starch generally showed higher L-value than that of native starch blend sheets. The hunter b-values in both native starch blends and epichlorohydrin treated starch blends increased with Increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. Tensile strength and percent elongation of sheets decreased with increasing starch contents. The degradability of blends under UV radiation increased with increasing starch contents in both blend types. The results represents that crosslinking of starch with epichlorohydrin may be a good method to improve miscibility of starch with petroleum-based materials.

• 수산해양기술연구
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• 제16권1호
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• pp.23-26
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• 1980

The pure polypropylen rope has been used for the head rope, and the lead cored polypropylen rope for the ground rope in the anchovy boat seine. These ropes revealed the disadvantage that deforms the net shape due to their elongation. Te improve the disadvantage, authors developed the rope of new construction which is cored by wires and wrapped by polypropylene fibers, 20mm in diameter for the head rope and 40tnm for the ground rope. To compare the physical properties of the improved rope with the conventional ones, some factors are valued and the following results are found. 1. The improved ropes rev~al some disadvantages, such as the head rope is heavier, the ground rope lighter, and both of them are stiffer than the conventional ones, contrary to the required condition of ropes) However no special difficulties are found in practical use. 2. The improved ropes display much advantages, such as elongation is 30 percent less, breaking strength is 35 precent greater, and elastic recovery is 10 percent greater than the conventional ones. Thus, it is considered that the improved ropes are more suitable for the head rope and the ground rope of the anchouy boat seine net than the conventional ones.

• Preventive Nutrition and Food Science
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• 제3권1호
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• pp.27-35
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• 1998

Starch-polyethylene films containing high molecular weight(NW) oxidized-polyethylene and prooxidant were prepared , and thermal -and bio-degradability of the films were determined. Increased levels of starch resulted in a corresponding reduction in mechanical strength of the films. However, the addition of high MW oxidized-polyethylene did not significantly reduce the percent elongation of the films. Thefilms containing high MW oxidized-polyethylene andproosicant were degreaded faster than those containing no aadditive during the heat treatment. The films lost their measureable mechanical properties when their weight-average MW(Mw) fell below 50,000. Biodegradability of the films was determined by a pure culture assay with either Streptomyces badius 252.S. setonii 75Vi2 or S. viridosporous T7A, and by an extracellulr enzyme assay using S. setonii 75vi2. The results from pure culture assay indicated that biomass accumulation on the film surface inhibited chemical and biological degradation of the films. The extracellular enzyme assay demonstrated decrease of percent elongation and increase of carbonyl index of the films. Therefore, extracellular enzyme assay could be used as a good method to evaluate biodegradability of the films.