• Textile Coloration and Finishing
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• v.16 no.1
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• pp.53-58
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• 2004

The preparation of responsive fibers from acrylic fibers is studied. Various responsive fibers, such as fibers which change their color on exposure to light or with change in temperature, have been developed and are used commercially However, the responsive material in these fibers are not the fiber itself but chemicals in microcapsules attached to the fibers by finishing, and few fibers exhibit responsive properties by itself. The partial hydrolysis of polyacrylonitrile fibers to obtain pH responsive fibers is presented in this paper. Partial hydrolysis was effected by control of the concentration of the sodium hydroxide used in the hydrolysis, hydrolysis temperature and time. The degree of hydrolysis was evaluated by nitrogen content of the hydrolyzed fibers and their response, change in length, to aqueous solutions of varying pH was studied by continually changing the pH. Significant changes in lengths with pH were observed and the gel transition behavior varied with the conditions of hydrolysis. The hysteresis of the length change was also studied to evaluate the possibilities of using hydrolyzed acrylic fibers as pH sensors.

• Mass Spectrometry Letters
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• v.3 no.2
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• pp.47-49
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• 2012

Myoglobin was hydrolyzed by microwave-assisted weak acid hydrolysis with 2% formic acid at $37^{\circ}C$, $50^{\circ}C$, and $100^{\circ}C$ for 1 h. The most effective hydrolysis was observed at $100^{\circ}C$. Hydrolysis products were investigated using matrixassisted laser desorption/ionization time-of-flight mass spectrometry. Most cleavages predominantly occurred at the C-termini of aspartyl residues. For comparison, weak acid hydrolysis was also performed in boiling water for 20, 40, 60, and 120 min. A 60- min weak acid hydrolysis in boiling water yielded similar results as a 60-min microwave-assisted weak acid hydrolysis at $100^{\circ}C$. These results strongly suggest that microwave irradiation has no notable enhancement effect on acid hydrolysis of proteins and that temperature is the major factor that determines the effectiveness of weak acid hydrolysis.

• Textile Coloration and Finishing
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• v.17 no.3 s.82
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• pp.16-25
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• 2005

In this research, we investigated hydrolysis of the ester crosslinking on cotton fabric treated with polymer of maleic acid(PMA), citric acid(CA) and combination of polymer of maleic acid and citric acid using Fourier transform infrared spectroscophy. The rate of hydrolysis of the ester crosslinkage increased with pH regardless of the type of polycarboxylic acid used and even after hydrolysis for 256 hour in pH 13_4 solution, the treated fabric retained $10-20\%$ ester crosslinkage. The durability to alkaline hydrolysis of the ester crosslinkage formed by CA was lower than that of by PMA and combination of poly(maleic acid) and citric acid indicating that the ester formed by CA on the cotton fabric is more susceptible to hydrolysis than that formed by PMA and combination of PMA and CA. The total amount of ester and polycarboxylic acid molecules removed from fabric increased with increasing hydrolysis time but the rate of hydrolysis of ester linkage were higher than that of removal of polycarboxylic acid molecule from the fabric. The characteristic of hydrolysis of fabric treated with combination of PMA and CA was related with the mixing ratio of PMA and CA in treating fabric.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.3
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• pp.52-58
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• 2011

Proton-NMR spectroscopic method was applied to kinetic study of concentrated sulfuric acid hydrolysis reaction, especially focused on 2nd step of acid hydrolysis with deferent reaction time and temperature as main variables. Commercial xylan extracted from beech wood was used as model compound. In concentrated acid hydrolysis, xylan was converted to xylose, which is unstable in 2nd hydrolysis condition, which decomposed to furfural or other reaction products. Without neutralization steps, proton-NMR spectroscopic analysis method was valid for analysis of not only monosaccharide (xylose) but also other reaction products (furfural and formic acid) in acid hydrolyzates from concentrated acid hydrolysis of xylan, which was the main advantages of this analytical method. Higher temperature and longer reaction time at 2nd step acid hydrolysis led to less xylose concentration in xylan acid hydrolyzate, especially at $120^{\circ}C$ and 120 min, which meant hydrolyzed xylose was converted to furfural or other reaction products. Loss of xylose was not match with furfural formation, which meant part of furfural was degraded to other undetected compounds. Formation of formic acid was unexpected from acidic dehydration of pentose, which might come from the glucuronic acid at the side chain of xylan.

• Food Science of Animal Resources
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• v.37 no.5
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• pp.646-653
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• 2017

Alcalase hydrolysis of liquid egg white was used to produce 5-hydroxytryptophan (HTP) under various conditions and investigate the sleep-potentiating activity of liquid egg white hydrolysate (LEH) on pentobarbital-induced sleep. Alcalase hydrolysis yielded the highest content of 5-HTP ($13.50{\mu}g/mL$), while neutrase hydrolysis showed the lowest 5-HTP content ($5.23{\mu}g/mL$). The liquid egg white to water ratio (1:1) was optimal for the production of 5-HTP with high amino-nitrogen (A-N) content and degree of hydrolysis. The 5-HTP, amino-nitrogen, and degree of hydrolysis increased until 24 h of hydrolysis and slightly increased thereafter during hydrolysis with 2% and 5% enzyme addition. 5-HTP administration at doses of 6 and 9 mg/kg significantly increased sleep duration and decreased sleep latency time compared to that in the control (p<0.05). LEH (150 mg/mouse), which was equivalent to 5-HTP at 6 mg/kg, significantly decreased sleep latency time and increased sleep duration time compared to that in the control (p<0.05). Oral administration of LEH showed sleep-potentiating effects because of 5-HTP. The sleep-potentiating activity of LEH may have occurred through 5-HTP in our pentobarbital-induced sleep model. LEH may be a valuable alternative to sleep enhancement and may be used as a sleep-potentiating agent.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.643-648
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• 1993

A simple approximate model using equivalent time at a reference temperature ($t_{eq}$) was derived to predict quality changes caused by temperature fluctuations. The validity and effectiveness of this model have been assessed with experimental data of sucrose hydrolysis. Kinetic parameters of sucrose hydrolysis were estimated by one step method using equivalent time at a reference temperature with linearly increasing temperature profile. Sucrose hydrolysis was a first order reaction, and the activation energy was 25.84 kcal/mol. The extent of sucrose hydrolysis of liquid model system under accelerated test with sinusoidal temperature fluctuations were determined. The proposed model yielded accurate prediction with the correlation coefficient in the range of $0.92{\sim}0.99$.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.3
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• pp.550-559
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• 1996

The Effect of protease (subtilisin Carlsberg) on the removal of hemoglobin as protein soil was studied. The hydrolysis characteristics of subtilisin Carlsberg was examined by electrophoretic techniques. The fragmentation patterns of hemoglobin were analyzed by SDS-PAGE. The hydrolysis efficiency was evaluated by analysis of protein bands shown on gels before and after hydrolysis by using densitometer. 1. The hydrolysis of hemoglobin by subtilisin Carlsberg was increased markedly with the increase of the enzyme concentration. 2. The hydrolysis of hemoglobin by subtilisin Carlsberg was effectively increased in proportion to increasing of the hemoglobin concentration up to a certain point, but it began to decrease above the point. 3. The hydrolysis of hemoglobin by subtilisin Carlsberg followed the first order kinetics, yielding a rate constant of $4.05\time10^{-4}S^{-1}s$. 4. The hydrolysis of hemoglobin by subtilisin Carlsberg was highest at $50^{\circ}C$ and was decreased markedly at $80^{\circ}C$. 5. The hydrolysis of hemoglobin was comparatively low at pH 7.0~8.0, and highest at pH 11.0.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.05a
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• pp.263-267
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• 2001

The changes of interfacial properties and microfailure degradation mechanisms of bioabsorbable composites with hydrolysis were investigated using micromechanical test and acoustic emission (AE). As hydrolysis time increased, the tensile strength, the modulus and the elongation of PEA and bioactive glass fibers decreased, whereas those of chitosan fiber changed little. Interfacial shear strength (IFSS) of bioactive glass fiber/poly-L-lactide (PLLA) composite was significantly higher than that two other systems. The decreasing rate of IFSS was the fastest in bioactive glass fiber/PLLA composite, whereas that of chitosan fiber/PLLA composite was the slowest. With increasing hydrolysis time, distribution of AE amplitude was narrow, and AE energy decreased gradually.

• Mass Spectrometry Letters
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• v.10 no.3
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• pp.79-83
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• 2019

Horse heart myoglobin (MYG) and bovine serum albumin (BSA) were hydrolyzed by microwave-assisted weak-acid hydrolysis for 10, 20, 30, 40, 50, and 60 min using 2% formic acid (FA) at $100^{\circ}C$. Generally, the number of identified peptides increased with increasing irradiation time, indicating that the duration of microwave irradiation is linked to the efficiency of hydrolysis. For MYG, irradiation for 60 min provided the highest number of identified peptides, the greatest sequence coverage values and the highest MASCOT score values among the investigated irradiation times. Irradiation of BSA for 50 min, however, yielded a greater number of peptides than irradiation for 60 min due to the generation of miscleaved peptides after microwave irradiation for 50 min.

• Elastomers and Composites
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• v.52 no.1
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• pp.1-8
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• 2017

Hydrolysis resistance and mechanical property changes of polyketone (POK)/glass fiber (GF) composites were investigated for GF concentrations varying between 30 and 50%. The hydrolysis resistance of GF filled POK and polyamide66 (PA66, hydrolysis resistant grade) composites were compared. As shown by the experimental results, increasing the immersion time of the composites in a monoethylene glycol (MEG)/water solution at $120^{\circ}C$ had no impact or resulted in slightly decreased mechanical properties such as the tensile strength, tensile modulus, and strain at break in case of POK composites, whereas the mechanical properties of PA66 composites showed a significant drop. Increasing GF concentrations increased the tensile strength, tensile modulus, flexural strength, and flexural modulus of POK composites; however, impact strength did not show significant changes. Hydrolysis mechanisms of POK and PA66 are discussed.