• Polymer(Korea)
• /
• v.32 no.5
• /
• pp.446-457
• /
• 2008

Three kinds of hydroxypropyl cellulose (HPC) derivatives: 6- (cholesteryloxycarbonyl) pentoxypropyl celluloses(CHPCs) with degree of esterification(DE) ranging from 0.6 to 3, 6-[4-{4'-(nitrophenylazo)phenoxycarbonyl}] pentoxypropyl celluloses (NHPCs) with DE ranging from 0.4 to 3, and fully 6-(cholesteryloxycarbonyl) pentanoated NHPCs (CNHPCs) were synthesized, and their thermotropic liquid crystalline properties were investigated. All the CHPCs and NHPCs with $DE{\leq}1.7$ formed enantiotropic cholesteric phases, whereas CNHPCs with 6-(cholesteryloxycarbonyl) pentanoyl DE(DEC) more than 1.6 exhibited monotropic cholesteric phases. On the other hand, NHPCs with $DE{\geq}2.4$ and CNHPCs with $DEC{\leq}1.3$ showed monotropic nematic phases. NHPCs with $DE{\leq}l$, as well as HPC, formed right-handed helices whose optical pitches (${{\lambda}_m}'s$) increase with temperature, while all the CHPCs formed left-handed helices whose ${{\lambda}_m}'s$ decrease with temperature. In contrast with these derivatives, NHPCs with $1.4{\leq}DE{\leq}1.7$ and CNHPCs with $DEC{\geq}1.6$ did not display reflection colors over the full cholesteric range, suggesting that the helical twisting power of the cellulose chain and the cholesteryl group highly depends on the chemical structure and DE of mesogenic group.

• Applied Chemistry for Engineering
• /
• v.10 no.4
• /
• pp.581-585
• /
• 1999

The surface treated hydroxypropyl methylcellulose(HPMC) which could adjust the soluble time was synthesized when 40 wt % glyoxal solution and $KH_2PO_4$ were sprayed and reacted. And also, the solution dynamic at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion characteristics at different ratios of two adding agents were identified If the surface of HPMC was treated with only glyoxal, the dispersion was observed in the neutral solution and the viscosity was increased after directly dissolved as the solution become alkali condition. But the fine-powder type of HPMC which reacted with glyoxal and $KH_2PO_4$ was dispersed regardless of pH of solution and observed that it was dissolved and its viscosity increased after elapsing some time. With increasing amount of glyoxal and $KH_2PO_4$, the soluble time was delayed. The reaction condition was about 60 min at $75{\sim}85^{\circ}C$. Especially, the removal process of organic solvent after reaction was not required due to reaction under water solution without organic during glyoxal and $KH_2PO_4$ treatment. And also, the HPMC which could adjust the soluble rate in water or organic solvent by changing the degree of substitution of HPMC was synthesized.

• Current Research on Agriculture and Life Sciences
• /
• v.32 no.1
• /
• pp.18-23
• /
• 2014

The present study examined the effect of cellulose ether on the compression and adhesion characteristics of rice dough using a rheometer. When increasing the amount of hydroxypropyl methylcellulose (HPMC), the adhesion strength consistently increased. However, the compression strength of the rice dough was the highest with 2% HPMC. When increasing the molecular weight and decreasing the water content, the compression and adhesion strength of the rice dough were both increased. Furthermore, the substitution type and degree of cellulose ether were also found to be key factors determining the compression and adhesion strength of the rice dough.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.3
• /
• pp.177-181
• /
• 2013

This study examined the effect of the molecular weight, substitution degree, and substitution type of cellulose ether on the mechanical properties of dried rice noodles. When increasing the molecular weight of the hydroxypropyl methylcellulose (HPMC), the bending strength of the dried rice noodles also increased. However, the bending strength of the rice noodles with added HPMCs was still lower than that of the wheat noodles. Meanwhile, the bending elongation of the dried rice noodles was higher than that of the wheat noodles and was increased when decreasing the molecular weight of the HPMC. In conclusion, the bending strength and elongation of dried rice noodles is affected by the substitution degree and type of cellulose ether.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2000.11a
• /
• pp.135-139
• /
• 2000

경제의 발전으로 인한 화학물질의 개발과 합성 등으로 새로운 물질들이 다양화됨으로서 화재에 대한 위험성이 날로 증대되고 있는 실정이다. 특히 산업현장에서 원료로 사용하거나 제품으로 만들어진 물질들이 착화원이 없음에도 불구하고 자연발화가 원인이 되어 화재폭발을 일으키는 사고가 빈번하고 있다. 자연발화에 관한 연구는 국내외적으로 진행되고 있지만 다종의 물질에 대한 연구에는 대단히 미흡한 실정이다. 그러므로 본 연구는 5사업장에서 생산되고 있는 HPMC에 대하여 자연발화에 대한 현상을 구명하여 이를 사용하는 작업장 등에 있어서 화재, 폭발의 예방에 대한 기초자료를 제공하고자 한다.(중략)

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2000.11a
• /
• pp.124-128
• /
• 2000

가연성분진을 생산, 가공, 수송하는 과정에서 분진폭발의 위험성은 항상 존재하고 있으며, 일단 분진폭발이 발생하면 인명과 재산상의 피해가 큰 대형사고의 경향을 띄게 되므로, 무엇보다 중요한 과제는 폭발예방대책을 강구하는 것이라 할 수 있다. 분진폭발을 예방하기 위해서는 폭발하한계, 최대폭발압력, 폭발압력상승속도, 최소착화에너지, 최저발화온도 등이 있으며, 이들 특성치는 실험을 통하여 파악하여야 한다.(중략)

• Journal of the Korean Ceramic Society
• /
• v.27 no.8
• /
• pp.1034-1042
• /
• 1990

Investigation for the preparation of high strength hardened cement paste using ordinary portland cement, hydroxypropyl methyl cellulose(HPMC) with various admixtures was carried out. The cement paste was mixed with 0.1 of water cement ratio by twin roll mill and cured 60 days in humidity chamber. When the quartz powder or white cement was added to the paste, the flexural strength was 900∼1000kg/㎠ and the Young's modulus was 8∼9×105kg/㎠. When the silicafume was added, the flexural strength was 800kg/㎠ and the Young's modulus was 6×105kg/㎠.

• Fashion & Textile Research Journal
• /
• v.24 no.2
• /
• pp.260-266
• /
• 2022

Cellulose fiber is a material used in various fields. It is the most used type of fiber because of its excellent hygroscopicity and dyeability. Recently, as natural fiber materials have been highlighted due to the influence of eco-friendliness and well-being, bamboo fiber has become a commonly used eco-friendly fiber. Cellulose fibers are part of the -OH hydroxyl group, which means they are more chemically reactive than synthetic fibers. In this study, the cationization properties of bamboo-cotton blended fabrics cationized using CHPTAC (3-chloro-2-hydroxypropyl trimethyl ammonium chloride) in the PDC (padding-drying-curing) method were investigated. Various characteristics according to cationization were studied through elemental analysis, FT-IR (fourier-transform infrared spectroscopy) analysis, X-ray diffraction analysis, TGA (thermogravimetric) analysis, and SEM (scanning electron microscope) analysis. The nitrogen content of the cationized bamboo-cotton blended fabric increased with an increase in the concentration of the cationizing agent CHPTAC, and it was seen to be highly bound to cellulose molecules. As a result of the FT-IR analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics were seen to be typical cellulose. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As the cationization progressed, micropores appeared on the surface of the blended fabric.

• Journal of Pharmaceutical Investigation
• /
• v.37 no.5
• /
• pp.275-280
• /
• 2007

A rapidly disintegration famotidine tablet formulation in the oral cavity was developed using microcrystalline cellulose (MCC) and low-substituted hydroxypropyl cellulose (L-HPC), or additionally cropovidone as an internal disintegrant. Effects of disintegrants on the disintegration time in vitro and hardness were evaluated. Average wetting time of the tablets prepared in scale-up manufacturing process was less than 15 sec. Among the formulations tested, the tablet prepared with crospovidone as an internal disintegrant and Emcocel $90M^{(R)}$ as an external disintegrant showed fastest disintegration. These results may suggest that crospovidone and Emcocel $90M^{(R)}$ possessed excellent wetting nature, which result in the rapid disintegration of tablet.

• Korean Journal of Food Science and Technology
• /
• v.31 no.1
• /
• pp.99-105
• /
• 1999

The preparation and the functional properties of methylcellulose (MC) and hydroxypropyl-methylcellulose (HPMC) edible films with and without calcium were investigated. All the prepared films exhibited transparent and whitish color with $2.38{\sim}3.55$ haze intensity. Tensile strength of MC films were stronger than HPMC films with and without calcium, and moreover addition of calcium increased tensile, but elongation of HPMC film was specially lower than the other films. Solubility of films did not differ with calcium addition but decreased with increasing viscosity in HPMC films. water vapor transmission rate (WVTR) of HPMC and MC film were not affected by calcium, but viscosity of film's raw material was important to determine WVTR in HPMC. Oxygen permeabilities of MC films were lower than those of HPMC films, and became lower with calcium addition. According to scanning electron microscope (SEM) observation on the surface characteristics, MC film with calcium had relatively uniform and smooth surface than HPMC films.