• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.4
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• pp.487-492
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• 2006

Acetylated rice starches were prepared by reaction of rice starch with acetic anhydride, and their physicochemical properties as a function of degree of substitution (DS) were evaluated. The percentage of acetyl group and DS were $0{\sim}2.71%\;and\;0{\sim}0.104$, respectively. DS increased with increase in acetic anhydride content. DS increased swelling power and solubility of rice starch. Light transmittance (%) values of acetylated rice starches were much higher than that of native rice starch and increased with increase in DS. Rapid Visco Analyzer initial pasting temperature of acetylated rice starches decreased with increase in DS, while peak viscosity and breakdown values increased. Starch gets showed a significant decrease in syneresis (%) with the increase in DS.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.153-160
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• 1999

Water soluble hydroxyalkyl methycellulose ethers are used in a variety of applications incluing building industry as a supplementary agent used for incresing adhesives, water retention capacity, workability and viscosity modify. Water retention capacity(WRC) is the capability to contain water in the ploymer chain under condition of being mixed with cement. In general, the WRC is affected by the viscosity, the adding amount, the particle size, the rate of dissolving and the amount of substituted chemical in cellulose ethers. In the other words, WRC is increased as higher the viscosity, more adding amount, finer the particle size and longer the dissolving time of cellulose ethers. This thesis investigated each factor that effect the WRC, particularly the relation between degree of substitution(DS), molar of substitution(MS) and WRC. It is observed that WRC is not nearly affected by DS of cellulose ethers, but is changes proportionally as MS increases in the narrow range(0.10~2.25)

• Journal of the Korean Wood Science and Technology
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• v.18 no.2
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• pp.25-35
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• 1990

To investigate the effects of swelling treatment by ammonia on characteristics of carboxymethy1cellulose(CMC) and CMC solution, the domestic kraft pulp pretreated with 5%, 10%, 15% and 20% $NH_4OH$ solution, was carboxymethylated by the standard method, and then the CMC prepared was tested. The physical properties of CMC and CMC solution, such as degree of substitution, transparency. viscosity, weight increase and solubility, were measured, and the comparison with commercial domestic CMC used as a food additive was done. The results obtained were as follows; 1. In CMC manufactured by standard solvent method, hardwood bleached kraft pulp(LBKP) was more substituted than safwood bleached kraft pulp(NBKP), and viscosity of NBKP was higher than that of LBKP. 2. When ammonia swelling treatment was done, degree of substitution gradually decreased with increasing concentration of $NH_4OH$, and degree of substitution of LBKP decreased with a larger range than that of NBKP. 3. When ammonia swelling treatment was done. transparency of CMC solution from LBKP was hardly effected, but in case of NBKP gradually increased with increasing concentration of $NH_4OH$. 4. When ammonia swelling treatment was done, viscosity of CMC solution was higher than that of CMC solution without ammonia swelling treatment. Especially, CMC of high viscosity could be manufactured in 5%, 10% concentration levels of $NH_4OH$. 5. In CMC manufactured from domestic NBKP, CMC at the range of 0.40 to 0.50 in DS was dispersed easily and quickly dissolved, and CMC at more than 0.50 in DS was dispersed slowly in water solution. 6. In comparison with commercial domestic CMC used as a food additive, CMC manufactured from domestic NBKP was higher in DS, and was lower in viscosity and transparency.

• Polymer(Korea)
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• v.33 no.3
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• pp.254-262
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• 2009

Nine kinds of hydroxypropyl celluloses (HPCs) with degree of substitution (DS) and molar substitution (MS) ranging from 2.10 to 2.71 and 2.3 to 6.7, respectively and seven kinds of fully butanoated HPCs (BPCs) based on the HPCs with $2.3\;{\le}\;MS\;{\le}\;6.7$ were synthesized, and the molecular characteristics of HPCs and the thermotropic liquid crystalline properties of the derivatives were investigated. MS was nearly equal to DS for small value of DS, but it became exceedly larger than DS for $DS{\gtrsim}1$, showing that in the later stages of reaction, propylene oxide preferentially adds to the side chains rather than the main chain. All the derivatives formed enantiotropic cholesteric phases with right-handed helical structures. The glass and clearing transition temperatures of both HPCs and BPCs were decreased with increasing MS. The optical pitches (${\lambda}_m'S$) of BPCs, as well as HPCs themselves, increased with increasing temperature. However, the ${\lambda}_m'S$ of both HPCs and BPCs at the same temperature increased with increasing MS. Moreover, the temperature dependence of ${\lambda}_m$ of HPCs was weaker than that of BPCs, suggesting that the helical twisting power of the cellulose chain highly depends on the length and chemical structure of the side chain introduced in cellulose chain.

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.81-90
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• 1992

The effect of acid treatment of cellulose on the substitution charateristics of carboxymethylation was studied in this paper. Five samples of hydrocellulose(HC), all prepared from ${\alpha}$-cellulose by hydrolysis with five reaction times and determined on average molecular weight and polydispersity, were carboxymethylated to carboxymethyl cellulose (CMC). The CMCs from HCs were examined upon degree of substitution(DS), distribution of carboxymethyl groups in anhydroglucose units of the cellulose, and unsubstituted anhydroglucose(USAG) content. The DS of CMCs increased with increasing the hydrolysis time except CMC from HC at 1 hour hydrolysis time. In carboxymethylation the availability of hydroxyl groups on anhydroglucose units in HCs was the highest on OH(2), and the relative availability of OH(6) increased with the increasing of the hydrolysis time. The USAG contents were more deviated than that calculated based on Spurlin's model, and had a strong tendency of decreasing with increasing the hydrolysis time. The reactivity of HC was lower than that of ${\alpha}$-cellulose and the relative availability of OH(6) in HC increased with the hydrolysis time.

• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.82-86
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• 1996

This study was performed to elucidate the effect of degree of substitution and degree of polymerization of CMC on the rheological characteristics of coating color which is consisted of calcium carbonate as pigment. The results were as follows: 1. It appeared that DP of CMC rather DS has an effect on the low shear viscosity of coating color. 2. According as shear rate increased, the effect of DP and DS on high shear viscosity of coating color decreased. 3. According to increasing DS and DP, the water retention of coating color increased.

• Korean Journal of Food Science and Technology
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• v.22 no.6
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• pp.651-658
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• 1990

Starch phosphates were prepared by dry heating, gelatinizing method and extrusion process using sodium tripolyphosphote (STPP) as a substitution reagent and their physicochemical properities were compared. In the preparation of starch phosphate by dry heating method(DSP), the effect of reaction temperature was the most significant to the DS(Degree of substitution). In the phosphorylation reaction with gelatinized starch(GSP), the substitution ratio was increased with increasing the reaction temperature, but the increase was insignificant above $85^{\circ}C$. By extrusion with the corn starch containing 2.0% STPP at various moisture contents of 20, 25 and 30%, the DS values of extrudate(WESP) were within the range of between 0.0066 and 0.0083. The starch phosphate(DSP) products showed lowering the gelatinization temperature, increasing the clarity of the starch paste. However, WESP showed higher gelatinization temperature than that of raw starch. The starch phosphate prepared by extrusion process showed lower apparent viscosity of paste than that of the DSP at same condition. All of starch phosphates showed reducing the tendency of the paste retrogradation.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.386-389
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• 1999

Amphoteric polymers have brought to papermakers' attention gradually. In this paper, a series of amphoteric starches with different cationic and anionic degree of substitution (DS) are prepared. Better product has been selected and used under different condition. As retention and drainage aids, amphoteric starches were used in shorter fiber length, weak strength and poor drainage bleached AQ-Soda wheat straw pulp. In neutral and alkaline papermaking system, when amphoteric starches contain 0.024-0.026 anionic degree of substitution (DS), it is shown that the higher the cationic degree of substitution (DS) in amphoteric starches, the better the filler retention. The filler retention is improved 12.5%, 30.3%, and 35.1% and 32.5% respectively by adding 1% amphoteric starch LS-L2 -1 (0.034), LS-L2-2 (0.040), LS-L2-3 (0.047) and LS-L2-4 (0.052). But the strength of handsheets if affected a little. By adding 2% Al2 (SO4)3 and 1.5% LS-L2-3 at pH 7.5, filler retention can be improved from 38% to 80%, and breaking length of sheet only decreases 3.2%. As dry strengthening aids, amphoteric starches were used in eucalyptus APMP. Amphoteric starches are used in eucalyptus APMP. The amphoteric starch LS-L2-2 is better dry strength aid. Adding 1% LS-L2-2 can improve breaking length 24.5%, burst index 42.9%, tear index 38.8%, folding endurance and density of the handsheets.

• Journal of the Korean Applied Science and Technology
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• v.26 no.4
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• pp.428-433
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• 2009

Cellulose triacetate (CTA) was prepared from cotton linter and pulps which contain various contents of $\alpha$-cellulose. CTA which contains 2.8 of degree of substitution (DS) and 222 of degree of polymerization (DP) was obtained from V-81 pulp under the heterogeneous system. The DS was measured by the titration method, and the DP was obtained by measurement of viscosity. FT-IR spectometer (FT-IR 6300, JASCO) was used to analyze the chemical structure of raw materials and cellulose triacetate, and X-ray diffractometer (X-pert MPD PW3040, Philips) was used to confirm the crystal structure and to calculate the relative crystallinity index (RCI). As $\alpha$-cellulose content in pulp increased, the acetylation yield increased. Besides with a kind of pulp, it contains insoluble residue which was mainly formed due to the formation of glucomannan triacetate and xylan diacetate during the esterification.

• Clean Technology
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• v.13 no.3
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• pp.201-207
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• 2007

Carboxymethylcellulose (CMC), which is water-soluble at room temperature, was synthesized from cellulose in this study. Experimental parameters included reaction temperature, time, concentration of NaOH, and monochloroacetic acid (MCA). In mercerization and etherification, solubility and degree of substitution (DS) increased when NaOH (or MCA) concentration increased and maximum solubility and DS were achieved when NaOH or MCA was 30%. The effect of MCA concentrations on the DS was larger than that of the NaOH concentration. Tensile strength of the CMC was decreased by the increases of reaction time, reagent concentration and reaction temperature. Tensile strength also decreased by NaOH and MCA. However, low decrease of tensile strength was observed in near neutral region.