• Applied Chemistry for Engineering
• /
• v.7 no.2
• /
• pp.387-392
• /
• 1996

Natural zeolite/epoxy resin composites were prepared and the cure kinetics was studied by dynamic DSC analysis. With the increments of natural zeolite content, the reaction starting temperature and the exothermic peak temperature were decreased. When diglycidyl ether of bisphenol A(DGEBA)/4,4'-methylene dianiline(MDA)/malononitrile(MN, 10phr) was filled with 20phr of zeolite, DSC thermogram had one peak and when it was filled with 30phr of zeolite, a shoulder appeared on the DSC thermogram. With the filling of 40phr of zeolite, DSC thermogram was separated into two peaks and the activation energy of the first peak, $Ea_1$ was 12.30 kJ/mol and that of the second peak, $Ea_2$ was 12.70 kJ/mol.

• Korean Journal of Food Science and Technology
• /
• v.25 no.4
• /
• pp.400-403
• /
• 1993

Gelatinization degrees of torn and waxy corn starches in the low-moisture environment were determined by DSC thermogram and enzymatic analysis, the results were compared each other As the moisture content increased from 20% to 70%, the enthalpy of endothermic peak of starch increased linearly in DSC thermograms. When the moisture content exceeded above 70%, the DSC enthalpy of starch remained constant in DSC thermogram. The enthalpies for gelatinization of corn and waxy corn starches were 3.23 cal/g and 4.2 cal/g, respectively. When gelatinization degrees of starches were measured by enzymatic analysis, the gelatinization degree increased linearly as the moisture content increased from 20% to 80%. A linear correlation between DSC and enzymatic analysis was obtained only when the moisture content was under 70%.

• Elastomers and Composites
• /
• v.21 no.1
• /
• pp.13-19
• /
• 1986

The effects of several vulcanizing accelerators on the determination of kinetic parameters of natural rubber vulcanizate was studied by DSC. Kinetic parameters were determined by means of the calculation procedures of Borchardt-Daniels and Oscillating Disk Rheometer (ODR) cure curve analysis, using both DSC exothermal thermogram and ODR cure curve. In order to examine the credibility in the DSC method the same compound which was und for DSC method was used for the comparison with the results of ODR data. Upon this method, kinetic rate constant (k), and Arrehenius parameter (Ea, ko, n) have been determined for rubber compounds via a new method using DSC thermogram and ODR cure curve. In the comparison of DSC and ODR results, kinetic parameters has shown good agreements between two results. Consequently, from the present studies, it is shown that the DSC thermoanalytical method can provide an alternate new method of kinetic study of rubber vulcanization.

• Korean Journal of Food Science and Technology
• /
• v.39 no.6
• /
• pp.637-643
• /
• 2007

In this report, we discussed the physiochemical characteristics of corn starch during the alkali gelatinization process. Here, solubility and the amounts of eluted polysaccharides and amyloses increased in proportion to the amount of alkali added. The X-ray diffraction patterns and DSC thermogram showed that in the early stage of alkali gelatinization, crystallinity of the starch granules was disrupted as compared with heat gelatinization. This resulted in the eluted amylose content, while granule sizes were hardly changed in the alkali treated corn starch. The endotherm peak in the DSC thermogram shifted toward a higher temperature region as the degree of gelatinization increased, suggesting that the retained starch granules were more compactly crystallized during alkali gelatinization than during the heat process. Thus, we concluded that during the alkali gelatinization of corn starch, the disruption of weak particles would occur first, before swelling of the granules.

• Korean Journal of Food Science and Technology
• /
• v.20 no.3
• /
• pp.331-337
• /
• 1988

The thermal properties of typical five Indica and five Japonica rice varieties were investigated by Differential Scanning Calorimetry (DSC). There was no significant difference in gelatinization temperature between Indica and Japonica varieties, but the average enthalpy of gelatinization was larger in Indica types than that in Japonica. However, the enthalpy of melting of amylose-lipid complex was larger in Japonica types than that in Indica types. The DSC thermogram of hydrolyzed rice residue included a smaller peak of gelatinization with narrow range of temperature. Retrogradation of gelatinized rice kernel was also determined with DSC theremograms. The endothermic peak areas clearly increased with increasing storage time at $4^{\circ}C$ so that the area could be used as a measure of the relative degree of retrogradation. The results indicated that Samgang variety(Indica) retrograded more rapidly than Chuncheong variety(Japonica).

• Textile Coloration and Finishing
• /
• v.14 no.6
• /
• pp.328-334
• /
• 2002

Nylon 6 staple ultramicrofiber(UMF, 0.074) and regular staple fiber (Regular, 2.0d) were annealed at In, 130, 160 and $180^\circ{C}$ under tension free for 10 min and U min. The treated fibers were dyed with Acid Red 18 and Blue n3. They were adjusted at PH 5.0 of dye bath in buffer solution of $CH_3COOH/CH_3/COONa(0.1mo1/1)$. Liquor ratio was kept at 1000:1. Dyeing rate of UMF annealed at $100^\circ{C}$ was decreased, but was increased for regular nylon. Also dye equilibrium of UMF at $100^\circ{C}$ was increased for Acid Red 18, but was decreased for Acid Blue 83. The intensities of X-ray diffraction peaks of UMF increased with increasing annealing temperature. Also the crystallinity of heat-sotted fibers by DSC thermogram was well agreed with the tendency of density Amino end group, moisture regain and water absorbency were decreased with increasing annealing temperature.

• Journal of the East Asian Society of Dietary Life
• /
• v.6 no.1
• /
• pp.85-92
• /
• 1996

The sensory and instrumental characteristics of Jeung-pyun made from various additives were investigated to improve the qualify of Jeung pyun and to know the effects of additives on Jeung-pyun preparation. In sensory evaluation of Jeung-pyun made from various additives, hardness was significantly lower by addition of soy bean flour, whole milk powder, and egg yolk. The cell uniformity of Jeung-pyun was significantly lower by addition of egg yolk and mugwort. And the dgree of bitterness Jeung-pyun containing soy bean flour and mugwort flour were significantly higher than that of control. Retrogradation of Jeung-pyun assessed from DSC thermogram and hardness measured by texturometer was delayed by addition of soy bean flour, and whole milk powder.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.42 no.3
• /
• pp.344-351
• /
• 1997

The experiment was conducted to examine the varietal variation in gelatinization of rice flour and adaptability to rice bread processing, and the interrelation among the relevant properties. IR 44 showed the lowest temperature of gelatinization onset(T$_{o}$ ) and the highest gelatinization enthalphy(ㅿH) measured by differential scanning calorimetry (DSC). The following lower T$_{o}$ was found with the order of Suweon 230＜Pusa-33-30＜T(N) 1, Daeribbyeo 1 and the next higher ㅿ.H was followed by the order of Pusa-33-30＞Suweon 230. IRAT 177 revealed the highest temperature of gelatinization onset and conclusion(T$_{c}$) and the following higher T$_{c}$ was found with the order of Pusa-33-30＞AC 27＞Nonganbyeo. The varietal range of T$_{o}$ and T$_{c}$ was 50.0~72.5$^{\circ}C$ and 70.2~87.4$^{\circ}C$, respectively. The rice materials tested can be classified by scatter diagram on the plane of upper two principal components contracted from DSC thermogram and various characteristics relevant to processing and sensory preference of rice bread by principal component analysis. AC27, Suweonjo and IR 44 among high-amylose rices showed better suitability to rice bread processing. The temperatures of gelatinization peak and conclusion of rice flour checked by DSC were significantly negatively associated with springiness of rice bread. The most properties relevant to processing and sensory preference of rice bread such as hardness, moistness, springiness, cohesiveness, specific loaf volume and distribution or size of air cell revealed the close correlation between each other.other.

• Journal of Adhesion and Interface
• /
• v.17 no.4
• /
• pp.136-140
• /
• 2016

In this study, a series of dimer acid-based polyamides with different diamines were synthesized by condensation polymerization and the polyamides were characterized by Fourier transform infrared spectroscopy (FT-IR). Effects of diamine structures on mechanical and thermal properties of polyamides were investigated. The tensile strength and lap shear adhesion strength of aromatic-based polyamide (DAP) were higher than those of aliphatic-based polyamide (DAH). In DSC thermogram, DAP has a high $T_g$ and $T_m$ compared with DAH. DAP's and DAH's softening point were $112-115^{\circ}C$ and $98-121^{\circ}C$, respectively.

• Korean journal of food and cookery science
• /
• v.10 no.1
• /
• pp.76-79
• /
• 1994

This study was carried out to examine changes in morpholgy and crystallinity of cowpea starch during preparation of chongpo-mook(starch gel food). It was known by photornicroscopy under polarized light and X-ray diffractometry that cowpea starch had lost its crystallinity at the temperature range of 70∼75$^{\circ}C$ It also was obserbed by scanning electron microscopy that overall shape of starch granules was maintained inspite of swelling to considerable extent at the range of 65∼75$^{\circ}C$, however, granules were folded after solubles were extracted out of them above 85$^{\circ}C$. Mechanism of gelation seemed to be formation of junction zones stabilien by groups of weak H-bonds, not by recrystalliztion according to the results of DSC thermogram of reheating of sample pan after cooling and X-ray diffractogram of reheated cowpea starch gel.