• Elastomers and Composites
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• v.40 no.1
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• pp.59-65
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• 2005

Zinc methacrylate(ZMA) was incorporated into ethylene-propylene diene rubber(EPDM) by direct mixing of the metal salt with the rubber or was in-situ prepared in the rubber matrix through neutralization reaction of zinc oxide(ZnO) and methacrylic acid(MAA). Tensile and tear tests showed that ZMA had a great reinforcing effect for the EPDM. It was also found that ZMA reinforced EPDM vulcanizates can retain their mechanical properties under thermo-oxidative aging. Moreover the incorporation of ZMA induces a substantial improvement in the adhesive strength of the EPDM onto aluminum substrate. The reinforcing effect and an enhancement in adhesion was greatly manifested when the ZMA is in-situ formed with an excess amount of ZnO. The extraordinary improvement in the properties is supposed to be related with the formation of ionic crosslink as well as the degree of dispersion or ZMA domain in the rubber matrix.

• Food Science of Animal Resources
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• v.31 no.5
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• pp.782-790
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• 2011

The effects of soy protein isolate (SPI) and red bean protein isolate (RBPI) on gelling properties of pork myofibrillar protein (MP) in the presence of microbial transglutaminase (MTG) were studied at 0.45 M NaCl. MP paste was incubated with MTG (0.1%) at various levels (0.1, 0.3, 0.5, and 1%) of SPI and RBPI before incubating at $4^{\circ}C$ for 4 h. The rheological property results showed that MP gel shear stress increased with increasing RBPI concentration. Cooking yield (CY) of the MP gel increased with increasing RBPI and SPI, whereas gel strength (GS) was not affected by adding RBPI or SPI. Thus, effects of incubation time (0, 4, 8, 10, and 12 h) were measured at 0.1% SPI and RBPI. GS values of the MP gel at 10 and 12 h were similar and were higher than those of the others. CY values were highest when RBPI (0.1%) was added, regardless of incubation time. The protein patterns indicated that incubating the MP with MTG for 10 h resulted in protein crosslinking between MP and RBPI or SPI. Based on these results, RBPI and SPI could be used as an ingredient to increase textural properties and cooking yield of meat protein gel.

• Resources Recycling
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• v.31 no.6
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• pp.52-59
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• 2022

Calcium silicate based cement (CSC) is a low-carbon cement that emits less CO₂ by up to 70% compared to ordinary Portland cement during its manufacture. Most developed countries have commercialized CSC, whereas Korea is still investigating the manufacturing characteristics and basic properties of CSC. This paper provides a review of methods for manufacturing CSC using domestic raw materials and discusses the possibility of CSC localization based on an evaluation of the basic physical properties of manufactured CSC. The experimental results of this study indicate that the primary mineral components of CSC were CS, C₃S₂ C₂S, and unreacted SiO₂. This suggests the possibility of manufacturing CSC using domestic raw materials that exhibit mineral compositions similar to that of theoretical CSC. The compressive strength of CSC mortar is less than 1MPa at the age of 7 d under wet curing. This implies that hydration does not affect the property development of CSC mortar. Meanwhile, during carbonation curing, the compressive strength is 56 MPa or higher after 7 d, which indicates excellent early strength development. Furthermore, results of Thermogravimetric Analysis Differential scanning calorimetry (TG/DSC) show that a significant amount of CaCO₃ is formed, which is consistent with the results of previous studies. This implies that carbonation is associated significantly with the properties of CSC.

• Tunnel and Underground Space
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• v.22 no.4
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• pp.266-275
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• 2012

In this study, a method is devised to implement a supercritical $CO_2$ ($scCO_2$) injection environment on a laboratory scale and to investigate the effects of $scCO_2$ on the properties of rock specimens. Specimens of shale and sandstone normally constituting the cap rock and reservoir rock, respectively, were kept in a laboratory reactor chamber with $scCO_2$ for two weeks. From this stage, a chemical reaction between rock surface and the $scCO_2$ was induced. The effect of saline water was also investigated by comparing three conditions ($scCO_2$-rock, $scCO_2-H_2O$-rock and $scCO_2$-brine(1M)-rock). Finally, we checked the changes in the properties before and after the reaction by destructive and nondestructive testing procedures. The swelling of shale was a main concern in this case. The experimental results suggested that $scCO_2$ has a greater effect on the swelling of the shale than pure water and brine. It was also observed that the largest swelling displacement of shale occurred after a reaction with the $H_2O-scCO_2$ solution. The results of a series of the destructive and nondestructive tests indicate that although each of the property changes of the rock differed depending on the reaction conditions, the $H_2O-scCO_2$ solution had the greatest effect. In this study, shale was highly sensitive to the reaction conditions. These results provide fundamental information pertaining to the stability of $CO_2$ storage sites due to physical and chemical reactions between the rocks in these sites and $scCO_2$.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.79-84
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• 2001

In this study, the effect of polyol structure(OH-value, functionality) on the reactivity, mechanical property and cell morphology of polyurethane foam and the possibility of replacing HFC-36smfc was examined by evaluating how each blowing agent(CFC-11, HCFC-l4lb, HFC-36smfc) affects the reactivity, mechanical property and cell morphology. Results of the experiment showed that as the functionality and OH-value of polyol increased, there was an increase in the temperature profile, reaction rate, density and compressive strength. However. as the functionality and OH-value increased. the ceil size became smaller The use of different kinds of blowing agents did not appear to have and significant influence on the temperature profile, reaction rate, density and compressive strength. The foam using HFC-365mfc produced more uniform cells compared to the foam using HCFC-l4lb.

• Polymer(Korea)
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• v.24 no.2
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• pp.201-210
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• 2000

To determine the effect of chain length of linear amine curing agents on the thermal and mechanical properties, standard epoxy resin, diglycidyl ether of bisphenol A (DGEBA) was cured with diethylenetriamine (DETA), triethylenetetraamine (TETA) and tetraethylenepentaamine (TEPA) in a stoichiometrically equivalent ratio. From this work, the effect of linear amine curing agents on the thermal and mechanical properties was significantly influenced by chain length of curing agents. In contrast, the results showed that the DGEBA/DETA system had higher values than the DGEBA/TETA and DGEBA/TEPA system in the density, shrinkage (%), thermal expansion coefficient, tensile modulus, and flexural strength. Whereas the DGEBA/DETA cure system had lower values than the DGEBA/TETA and DGEBA/TEPA cure system in the maximum exothermic temperature, conversion (%), and T$_{g}$. These findings imply that the differences in the maximum conversion about the chain length of curing agents affect the thermal and mechanical properties.s.

• Composites Research
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• v.17 no.6
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• pp.44-51
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• 2004

To determine the effect of numbers of nitrogen atom bonded at ethyl group included in main chain of linear amine curing agents of epoxy-cure systems on the thermal and mechanical properties, standard epoxy resin DGEBF was cured with DETA, TETA and TEPA in a stoichiometrically equivalent ratio. From this work, the effect of curing agents of the DGEBF/amine systems oil the thermal and mechanical properties was significantly influenced by numbers of nitrogen atom of curing agents. The results showed that heat of reaction increased, and maximum exothermic temperature decreased with the decrease of numbers of nitrogen atom. In case of cured systems, density and maximum conversion(%) had no relation to numbers of nitrogen atom, but flexural modulus and tensile modulus increased with the decrease of numbers of nitrogen atom in main chain. Thermal stability, shrinkage(%), Tg, tensile and flexural strength showed irregular tendency having nothing to do with numbers of nitrogem atom at a sight. This findings imply that the differences in the maximum conversion(%) about the chain length of curing agents affect the thermal and mechanical properties.

• Elastomers and Composites
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• v.22 no.3
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• pp.195-203
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• 1987

In this study, as one of the developing ways of the functional elastomer, improvement of the functionality of CB-BR was attempted through moisture curing reaction. The curing reaction of CB-BR was determined with an use of 3-aminopropyltriethoxysilane(APS) as a crosslinking agent, also a solution reaction with an active chlorine of CB-BR was elucidated by using a reaction kinetics theory and a study of physical property was made through moisture curing on the compound of 3-aminopropyltriethoxysilane and CB-BR The results of this study obtained are as follows : 1) CB-BR reacted easily with APS in the liquid state and the reaction rate coefficient and activation energy were as follows : 2) Optimum pressure condition of moisture cured elastomer(CB-BR+APS) was 20 minutes at $150^{\circ}C$, and the crosslinked elastomer was close to the theoretical value (q=1) for Flory's equation($\frac{\alpha}{\alpha-1}=q{\nu}RT$)

• Tunnel and Underground Space
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• v.8 no.4
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• pp.321-331
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• 1998

A reliable analysis of tunnelling is needed to accomplish technically sound design and safe and economical construction. For the reliable analysis, a series of procedures of construction which include excavation and support stages must be considered. In this study, rock-support response behavior is studied and simulated in 2-D and 3-D finite element methods. Through the analysis of rock-support response behavior, the effects of the properties of shotcrete on the load distribution ratio can be quantified. The load distribution ratios for different rock types, different unsupported spans and various lateral earth pressure coefficients can be determined from the results of the 3-D finite element analysis. This load distribution ratios can be applied to a practical tunnel design through understanding of the trend of those various factors affecting the rock-support interaction.

• Elastomers and Composites
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• v.43 no.1
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• pp.18-24
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• 2008

An oligomeric diol was utilized as a modifier for the reaction rate and mechanical properties of a RT-castable polyurethane elastomer. Both the reaction rate and the tensile strength of the blend samples, in which the modifier and the base resins were mixed with one-shot method, showed an exponential decrease as the increase of modifier concentration. Thermal analysis method of Kissinger was also effectively applied in the present study, showing good linearity in the plot of ln $(q/T^2_p)$ vs. $(1/T_p)$ and activation energy $E_a$ of 44.80 kJ/mol, which is similar to the general castable polyurethane. In the mechanical properties, remarkable decrease of strength was found by the addition of modifier concentration range up to about 20 phr, while characteristic elongation property of the elastomer, high elongation at lower strength, was observed over 20 phr of the modifier. Exponential decrease of the break strength of the blend sample exhibited that the mechanical properties of the blend might be considerably sensitive to the modifier concentration.