• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.71-75
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• 1998

Liquid crystalline compounds with amine terminal group and related linear and cross-linked liquid crystal polymers with epoxy resin structure were synthesized and characterized to develope matrix materials for polymer dispersed liquid display applications. Both linear and crosslinked side chain type liquid crystal polymers made with aromatic amine mesogens and ethylene glycol diglycidyl ether exhibited nematic texture as shown by polarized optical microscope(POM) and their transition temperatures were determined both by DSC and POM. Liquid crystal polymer samples also showed even-odd effect as the spacer length of aromatic amine mesogens were varied, however, the effect was samller than that of low molecular weight mesogens. Changes of nematic-to-isotropic transition($T_{NI}$) of crosslinked type polymer liquid crystals were also disscussed in relation to the concentration change of crosslinking agent 1,10-diaminodecane.

• Polymer(Korea)
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• v.38 no.3
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• pp.371-377
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• 2014

The effect of modification conditions on the physical properties of polydimethyl siloxane modified epoxy (PDMSME) was investigated. The number of ring opened epoxy attached to polydimethylsiloxane (PDMS) by silane coupling agent affected the physical properties of undercoating materials. The flexibility of thin coating was enhanced by PDMSME and the increase of ring opened epoxy attached to PDMS resulted in the increase of hardness by the crosslinking in the present with moisture. The higher molecular weight of PDMS caused the lowering of hardness while the surface contact angle increased due to the high silicone content in PDMS. The viscosity of silicone modified epoxy coating materials decreased with increasing of molecular weight of PDMS due to the lowering of entanglement of PDMSME molecules by acetone solvent and consequently, the smooth undercoated surface was obtained.

• Fashion & Textile Research Journal
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• v.14 no.2
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• pp.311-319
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• 2012

The purpose of this study is to investigate the dyeing property of gromwell on modified cotton fabric by chitosan. Modified cotton fabrics were manufactured by crosslinking agent epichlorohydrin in the presence of chitosan. Gromwell colorants were extracted with methanol. Modified cotton fabrics dyed using gromwell were post-mordanted using Al, Fe and Cu. The dyeability (K/S) and color factors (L, a, b, ${\Delta}E$ and h) of modified cotton fabrics were measured by computer color matching. Additionally the fastness to washing and light were also investigated. The dye-uptake of modified cotton fabrics increased with the dyeing time. The saturated dyeing time was about 10minutes at $50^{\circ}C$. The dyeability (K/S) was remarkably increased with increasing content of chitosan because of having a amine group of chitosan. Modified cotton fabrics were dyed yellowish red by non and Fe mordanting, blueish red by Al and Cu mordanting, respectively. The washing fastness of non, Al, Fe and Cu mordant in the presence and absence of chitosan were increased $1{\rightarrow}2$, $3{\rightarrow}4$, $4{\rightarrow}4-5$ and $4{\rightarrow}4-5$ respectively. And light fastness of non, Al, Fe and Cu mordant in the presence and absence of chitosan were increased $1{\rightarrow}1-2$, $1{\rightarrow}1-2$, $1.2{\rightarrow}2.3$ and $1-2{\rightarrow}2$ respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.4
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• pp.95-104
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• 2004

A styrene solution of waste expanded polystyrene with a crosslinking agent and an initiator was used as a binder for waste wood-plastic composite panels. The waste wood-plastic composite panels are prepared with various binder contents and filler-binder ratios by using a hot press molding method. The apparent density of the composite panels is increased with increasing binder content and filler-binder ratio, while their water absorption and expansion in thickness are decreased with increasing binder content and filler-binder ratio. The maximum flexural strength and wet flexural strength of the composite panels are obtained at a binder content of 35% and a filler-binder ratio of 0.8. Decreases in the flexural strengths of the composite panels due to water immersion at 20 and $100^{\circ}C$ are hardly recognized at binder contents of 30% or more.

• Membrane Journal
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• v.14 no.2
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• pp.117-125
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• 2004

Proton exchange membrane composed of PVA/PAM/ZrP was prepared and effect of PAM and ZrP contents on properties and performance of the membrane were investigated. PAM as a crosslinking agent was mixed into PVA solution with different concentration (7∼11 wt%) and the PVA/PAM solution was cast to prepare PVA/PAM crosslinked membrane. The membrane was treated in the solution of zirconyl chloride and phophoric acid to make a PVA/PAM/ZrP composite membrane. Methanol permeability, ion conductivity, swelling and ion exchange capacity of the membranes with different ZrP concentration were $10^{-8}∼l0^{-6}$ $\textrm{cm}^2$/sec, $10^{-3}~10^{-2}$ S/cm, 0.26∼1.17 g $H_2O$/g membrane and 2.59∼5.1 meq/g membrane, respectively. Hethanol permeability and ion conductivity of the PVA/PAM/ZrP membrane were improved by 18% and 23%, respectively, compared to those of the PVA/PAM membrane.

• Membrane Journal
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• v.23 no.3
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• pp.245-250
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• 2013

In this study, the pervaporation separation characteristics were investigated for the iso-propyl alcohol (IPA)-water system using PDMS dense membranes. The ratio, 9:1 and 10:1, of the basic material based on RTV-655 and crosslinking agent were used to prepare dense membranes at the reaction temperatures, 40, 60, and $80^{\circ}C$. And these resulting membranes were characterized by pervaporation technique in terms of permeabilities and separation factors for the feed composition of IPA 85 wt% at the operating temperatures, 25, 35, 45, and $55^{\circ}C$. Typical results of permeabilities $148g/m^2{\cdot}hr$ at $55^{\circ}C$ for 9:1 membrane and the selectivity 17 at $55^{\circ}C$ for 10:1 membrane were obtained, respectively.

• Fashion & Textile Research Journal
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• v.10 no.5
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• pp.748-755
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• 2008

The purpose of this study is to investigate the effect of chitosan treatment on the dyeing of cotton fabric using charcoal as colorants. Particle size of charcoal, dyeability(K/S), SEM morphology of dyed fabrics and color fastness were also investigated. In this study, cotton fabrics were treated with a crosslinking agent epichlorohydrin in the presence of chitosan to provide the cotton fabrics the dyeing properties of natural dye by the chemical linking of chitosan to the cellulose structure. The results obtained were as follows; Mean average diameter of charcoal was 1.44 ${\mu}m$. According to various conditions, the dyeing effects of 1% chitosan treatment on the dyeing of cotton fabrics using charcoal were the highest with 10%(owb) of charcoal at $90^{\circ}C$ for 120minutes and non-treatment of cotton fabrics were the highest with 15%(owb) of charcoal at $90^{\circ}C$ for 150minutes. Overall, K/S value of 1% chitosan treatment of cotton fabrics on the natural dyeing using charcoal was higher than non-treatment of cotton fabrics. It was observed the surfaces of cotton fabrics treated with chitosan were adsorbed with charcoal powders of particle size more than a non-treated chitosan fabric by SEM. The cotton fabrics were dyed with blackish gray color by charcoal gradually according to treating chitosan. The K/S value, that is indicative of dye affinity, became higher as the increase of treated chitosan concentration. The color fastness of charcoal, washing and light fastness was excellent as 4-5 grade.

• Fashion & Textile Research Journal
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• v.10 no.4
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• pp.552-559
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• 2008

Recent days, various inner wears, sheets and interior goods are manufactured using materials dyed with loess emphasizing its improved blood circulation, metabolism, anti-bacterial, deodorizing properties, and far-infrared ray emissions. The purpose of this study is to investigate the effect of chitosan treatment on the dyeing of cotton fabric using loess as colorants. Particle size of loess, the morphology and dyeability(K/S) of chitosan crosslinked cotton fabrics, and washing durability of loess dyed cotton fabric were investigated. In this study, cotton fabrics were treated with a crosslinking agent, epichlorohydrin, in the presence of chitosan to improve the dyeing properties of cotton fabrics with natural dye by the chemical linking of chitosan to the cellulose structure. This process was applied by means of the conventional mercerizing process. The results obtained were as follows; Mean average diameter of loess was $1.13{\mu}m$. According to various conditions, the optimum dyeing conditions for cotton fabrics pretreated by 1% chitosan treatment was where 10%(owb) of loess was applied at $90^{\circ}C$ for 120minutes, while for cotton fabrics without chitosan treatment was where 15%(owb) of loess was applied at $90^{\circ}C$ for 150minutes. Overall, K/S value of loess dyed cotton fabric pretreated with 1% chitosan was higher than that of cotton fabrics without chitosan treatment. The Color fastness, washing fastness and light fastness of loess were excellent as 4-5grade.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.136-144
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• 1996

Polyacrylic super absorbent polymer(SAP) containing sorbitol was synthesized by inverse-suspension polymerization method. Sodium acrylate and acrylic acid were used as a monomer, ethylene glycol dimethacrylate(EGDMA) and glycerol polyglycidyl ether(GPGE) were used as a crosslinking agent, potassium persulfate(PPS) was used as an initiator, and cyclohexane was used as a solvent. Content of sorbitol was from 10mol% to 50mol% according to the mol ratio of acrylic acid monomer. The size distribution of the round shaped polymeric particle was $177{\sim}707{\mu}m$. Absorption amount of the polymer containing sorbitol was 785 to 1086 times of the polymer weight in distilled water, was 50 to 83 times in 0.9 % NaCl solution. Absorption and retention amount of the polymer were decreased with increasing the amount of sorbitol, but the polymer has an endothermic property which is +5 cal/g SAP.

• YAKHAK HOEJI
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• v.36 no.3
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• pp.212-219
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• 1992

Although oral route is the most convenient route for drug administration, the short and variable transit of drug through GI tract restricts the sustained drug absorption after oral administration. Thus, for sustained absorption of drugs, it is desirable to prolong the GI transit time by retaining the dosage forms in the stomach. In this study, the enzyme-digestible swelling hydrogel was synthesized by heating the mixed solution of N-vinyl-2-pyrrolidone[monomer], acrylated albumin[crosslinking agent] and proxyphylline[drug] at $65^{\circ}C$ for 10 hours in the cylindrical test tube. The resultant hydrogel tablet (diameter; 0.77 cm, thickness; 0.47 cm) was designed to swell in the gastric fluid after oral administration to such a size that passing through the pylorus could be inhibited during the drug release. After releasing drug, the hydrogel was expected to be degraded by pepsin, an enzyme in the stomach, and eventually solubilized. Actually, the hydrogel synthesized in the study swelled to a size larger than the diameter of the pylorus ($1.3{\pm}0.7$ cm) and slowly digested in the presence of pepsin. Drug release from the hydrogel was prolonged up to about 12 hours. The swelling kinetics was dependent on albumin acrylation time, drug content and gel thickness. Particularly the gel thickness was the most important factor that influences on drug release. By adjusting these factors, the albumin-crosslinked hydrogel was expected to be retained in the stomach for up to 60 hours and used as a potential platform of drugs for long-term GI absorption.