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Takigami, Machiko*; Nagasawa, Naotsugu; Hiroki, Akihiro; Kasai, Noboru; Yoshii, Fumio; Tamada, Masao; Takigami, Shoji*; Shibata, Takuya*; Aketagawa, Yasushi*; Ozaki, Masuo*
Transactions of the Materials Research Society of Japan, 35(3), p.647 - 650, 2010/09
There are many livestock farmers in Gunma Prefecture. Many of the farms are located under Mt. Akagi and Haruna, which attract tourists. Furthermore, rivers around the mountains are source of water supply to metropolitan area. Therefore, the waste treatments are very important. Regulations of smell and COD (chemical oxygen demand) are severe in Gunma Prefecture. Although there is no regulation for color of drain water, color in secondary treated water from livestock urine waste has been one of the major concerns for livestock farmers. The color is a metabolite of microorganisms and not easy to be removed. People have tried to remove the color by ozone treatment, absorption using activated carbon or soils. An absorbent was prepared by radiation grafting; fibers were irradiated with 
Co 
-rays and some kinds of monomers were grafted onto the fibers. The absorbent thus prepared were used to decolorize the secondary treated water. The color and COD were removed by the absorbent, however, COD removal was more difficult than decolorization. Degree of grafting (weight increase expressed in % by grafting reaction to initial weight of the fiber), treated water/absorbent ratio, flow rate of treated water, and direction of flow affected color and COD removal. The used absorbent could be used repeatedly after washing.
Kasahara, Takamitsu*; Takigami, Machiko*; Nagasawa, Naotsugu; Takigami, Shoji*
Transactions of the Materials Research Society of Japan, 34(3), p.395 - 398, 2009/09
no abstracts in English
Takigami, Machiko*; Hiroki, Akihiro; Nagasawa, Naotsugu; Kasahara, Takamitsu*; Takigami, Shoji*; Tamada, Masao
Transactions of the Materials Research Society of Japan, 34(3), p.391 - 394, 2009/09
Carboxymethyl cellulose (CMC) with different molar mass was prepared by acid hydrolysis at 121
C. CMC thus prepared was mixed with citric acid aqueous solution to form CMC-acid gel. By replacing sodium existing as counter ion in carboxymethyl group with hydrogen, CMC molecules coagulate and hydrogen bonds are formed among CMC molecules. The CMC-acid gel prepared in that way was subjected to evaluation of gel fraction, water absorption and mechanical properties. Gel fraction was higher in CMC with higher molar mass than that in CMC with lower molar mass at short incubation time. However, there was no difference in gel fraction attributable to molar mass of CMC after long time incubation. CMC with higher molar mass crosslinked more easily than CMC with lower molar mass. The gel made of CMC with lower molar mass was softer and absorbed more amount of water than that with higher molar mass. All the results were elucidated by number of hydrogen bonds in CMC molecule. The gel made of higher molar mass CMC becomes stiff and brittle after long time incubation, however, the gel made of lower molar mass CMC keeps softness and strength longer.
Kasahara, Takamitsu*; Takigami, Machiko*; Nagasawa, Naotsugu; Prawitwong, P.*; Takigami, Shoji*
Transactions of the Materials Research Society of Japan, 33(4), p.927 - 930, 2008/12
Carboxymethyl cellulose (CMC) forms a gel when mixed with acid as a result of replacement of sodium in carboxymethyl group with hydrogen; hydrogen bonds are formed among CMC molecules. CMC gel gets new property by mixing with other materials. Konjac mannan (KM) is a water soluble glucomannan with high molar mass and has high viscosity in low concentration aqueous solution. CMC gel is expected to have more elasticity by mixing with KM. Novel CMC-KM mixture gel is made by two processes; (1) mixing CMC with KM solution, (2) immersion of CMC-KM mixture in hydrochloric acid aqueous solution. Interaction of CMC and KM was studied by using KM with different molar mass. Molar mass of KM easily decreases by -irradiation. The effect of KM molar mass on characteristics of CMC-KM mixture is examined using tensile test fixture.
Kasahara, Takamitsu*; Takigami, Machiko*; Nagasawa, Naotsugu; Prawitwong, P.*; Tamada, Masao; Takigami, Shoji*
JAEA-Review 2008-055, JAEA Takasaki Annual Report 2007, P. 45, 2008/11
Carboxymethyl cellulose (CMC) forms a gel when mixed with acid as a result of replacement of sodium in carboxymethyl group with hydrogen; hydrogen bonds are formed among CMC molecules. CMC gel gets new property by mixing with other materials. Konjac mannan (KM) is a water soluble glucomannan with high molar mass and has high viscosity in low concentration aqueous solution. CMC gel is expected to have more elasticity by mixing with KM. Novel CMC-KM mixture gel is made by two processes; (1) mixing CMC with KM solution, (2) immersion of CMC-KM mixture in hydrochloric acid aqueous solution. Interaction of CMC and KM was studied by using KM with different molar mass. Molar mass of KM easily decreases by -irradiation. The effect of KM molar mass on characteristics of CMC-KM mixture is examined using tensile test fixture.
Makabe, Takeshi*; Prawitwong, P.*; Takahashi, Ryo*; Takigami, Machiko*; Nagasawa, Naotsugu; Takigami, Shoji*
Transactions of the Materials Research Society of Japan, 33(2), p.471 - 474, 2008/06
Konjac mannan (KM) is a water soluble glucomannan with high molar mass. KM aqueous solution shows extremely high viscosity. The effects of -rays irradiation and acid hydrolysis on molar mass were studied. The hydrolysis was carried out using citric acid. Characteristics of the irradiated and hydrolyzed KM were investigated using GPC-MALLS and a viscometer. The chemical structure of KM scarcely changed by both treatments. Molar mass of the irradiated KM decreased gradually with increasing dose. Molar mass of the hydrolyzed KM also decreased gradually with acid concentration. The viscosity of both treated KM aqueous solutions decreased with decreasing molar mass. High molar mass KM solution showed pseudo-plastic fluids behavior of the non-Newtonian fluid at dilute region and changed to Newtonian fluid with decrease of molar mass. Low molar mass KM solution showed behavior of Newtonian fluid at semi-dilute region. The critical concentration at the overlap limit of KM solution increased with decreasing of molar mass.
Takigami, Machiko*; Amada, Haruyo*; Nagasawa, Naotsugu; Yagi, Toshiaki; Kasahara, Takamitsu*; Takigami, Shoji*; Tamada, Masao
Transactions of the Materials Research Society of Japan, 32(3), p.713 - 716, 2007/09
Carboxymethylcellulose (CMC) gel was formed by addition of acid to CMC (CMC-acid gel). Gel fraction (weight of insoluble part/initial CMC weight) was calculated after removing uncrosslinked CMC by immersing the CMC-acid gel in water. It increased with acid concentration. Mechanism of CMC-acid gel formation was elucidated by aggregation of CMC molecules as the result of replacement of sodium in carboxyl group with hydrogen. Gels could be prepared by three different procedures; (1) mixing CMC and acid, (2) immersion of CMC or -irradiated CMC pastes in acid, and (3) -irradiation of CMC-acid gel. Gels with different elasticity and hardness were prepared changing degree of substitution of CMC, molar mass of CMC, species of acid, concentrations of acid and CMC, and application of -irradiation.
Takigami, Machiko*; Nagasawa, Naotsugu; Takigami, Shoji*; Tamada, Masao
no journal, ,
Carboxymethylcellulose (CMC) is one of the chemically modified carbohydrates used in food industry as thickener, stabilizer and disperse agent. The applicable field can be expanded by CMC gelation, which has been induced by ionizing radiation or crosslinking agents. We found a novel CMC gel formed by mixing CMC powder and acid solution. After mixing, the gel fraction (weight of gel/weight of gel and sol) increased with the increase of gelation time and the rise of temperature. The high concentration of acid accelerated the gelation. Edible acids can be used for the preparation of the gels. The resulting gels had elasticity, which was not observed in radiation-induced crosslinked gels. The elasticity could be controlled by selecting the CMC having the different degree of substitution and the molar mass, the kinds of acid, and the conditions such as concentrations of acid and CMC, time and temperature of gelation. Among them, the pH was the dominant factor to determine the properties of the gel. There was a correlative relationship between the compressive strength of the gel and pH. This result implied the gelation mechanism as follows; sodium in the carboxymethyl group is replaced by hydrogen in acid solution. Meanwhile the decrease of CMC solubility causes the aggregation of CMC molecules, and hydrogen bonds are formed. Gels formed in this way had comparable stability to radiation-induced crosslinked gels.
Takigami, Machiko*; Hiroki, Akihiro; Nagasawa, Naotsugu; Kasahara, Takamitsu*; Takigami, Shoji*; Tamada, Masao
no journal, ,
no abstracts in English
Takigami, Machiko*; Hiroki, Akihiro; Nagasawa, Naotsugu; Kasahara, Takamitsu*; Takigami, Shoji*; Tamada, Masao
no journal, ,
Takigami, Machiko*; Nagasawa, Naotsugu; Takigami, Shoji*; Tamada, Masao
no journal, ,
CMC (carboxymethyl cellulose) is a water-soluble polymer derived from cellulose and has many applications such as food additives, textile printing, oil drilling and pharmaceuticals. By crosslinking CMC molecules, to say gelation, usage of CMC has been extended to other fields. Crosslinking of CMC has been performed using multivalent metal ions, crosslinking agents and radiation to paste-like CMC. We found that CMC formed gel when mixed with acid. The mechanism was elucidated by the following processes. Commercial CMC is in a form of sodium salt owing to its manufacturing processes. When CMC is mixed with acid, sodium existing as a counter ion of carboxymethyl group is replaced by hydrogen. As CMC in acid form is hardly soluble in water, CMC molecules aggregate and hydrogen bonds are formed among CMC molecules. CMC-acid gel can be formed using any kinds of acid, and the characters depend on the combination of CMC and acid. Basically, CMC gel thus obtained is elastic, adherent and strong. Such properties are suitable for the application of CMC-acid gel to cosmetic, medical and leisure fields. Addition of some other materials provides CMC-acid gels having other properties. Applications of CMC-acid gels will be shown at the conference.
Takigami, Machiko*; Hiroki, Akihiro; Nagasawa, Naotsugu; Takigami, Shoji*; Tamada, Masao
no journal, ,
We reported previously that carboxymethyl cellulose (CMC) formed a gel when mixed with acid. As the sodium as a counter ion of carboxymethyl group in CMC is replaced by hydrogen, CMC molecules aggregate gradually, resulting in CMC gels. The CMC gels formed by hydrogen bonds were elastic and strong compared to gels prepared by only radiation. In this study, we found that the properties of the CMC gels can be improved by the addition of other materials besides CMC and acid. Gels made of CMC, acid, and polyol such as propylene glycol and ethylene glycol were stronger mechanical strength than the gels made of CMC and acid. Although the gel made of CMC and acid lost a shape in just a week, the gel with 45% of propylene glycol exhibited the morphological stability for over two years. Furthermore, water absorbency and water retention ability was controlled by the additive amount of polyol. The difference between gels containing and not containing polyol was distinct when less amount of CMC was used.
Takigami, Machiko*; Nagasawa, Naotsugu; Hiroki, Akihiro; Takigami, Shoji*; Tamada, Masao
no journal, ,
Carboxymethylcellulose (CMC) is one of the chemically modified carbohydrates used in wide areas as thickener, stabilizer and disperse agent. The applicable field can be expanded by CMC gelling, which has been induced by ionizing radiation, crosslinking agents, multivalent metal ions or repeated freeze-thaw cycles. We found a novel CMC gel formed by mixing CMC powder and acid solution. The resultant gel was soft, elastic and strong. Any acid could be used to form gel. FT-IR spectra of the gels were the same regardless of the species of acids. The higher the acidity of the acid, the faster the gel formation. As there is no trace of acid in the gel, the mechanism of gel formation was elucidated as follows: (1) Sodium existing as counter ion of carboxymethyl group is replaced by hydrogen in acid solution. (2) CMC solubility in water decreases because of the replacement of sodium with hydrogen and it causes the aggregation of CMC molecules. (3) Hydrogen bonds are formed among CMC molecules and CMC hydrogel is formed. The physical properties of the CMC hydrogel can be controlled by the following factors. CMC: Degree of etherification, molecular weight, concentration, Acid: Species, concentration, Others: Temperature, Time, combination of CMC and acid. The gel is expected to be used in medical service, nursing care, foods, commodity and cosmetics etc.
