• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.90-95
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• 2014

Nylon66 extrudates as a function of the extrusion number were prepared by a twin screw extruder. Chemical structures, thermal properties, melt index, crystal structures, mechanical properties such as the tensile strength, elongation at break and impact strength, and rheological property were measured by FT-IR, $^1H$-NMR, melt indexer, DSC, TGA, XRD, universal tensile tester, Izod impact tester, and rheometer. FT-IR and $^1H$-NMR characterizations indicated that the number of extrusions did not affect the chemical structure. The decrease in the molecular weight was checked by the melt index of extrudates. There were no effects of the thermal history on the melting and degradation temperature. The tensile and impact strength and modulus were found to be similar, regardless of the number of extrusions, but the elongation decreased significantly. The complex viscosity of extrudates at low frequencies decreased with the extrusion number. No structural changes after extrusion were confirmed from the fact that there was no change in the slope and shape of G'-G" plot.

• Journal of the Korean Society of Food Culture
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• v.18 no.6
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• pp.506-514
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• 2003

The effects of Japanese apricot(Prunus mume Sieb. et Zucc.) flesh on baking properties of white breads were investigated by evaluation of specific loaf volume, pH, acidity, rheological property, color and sensory quality. Bread was processed by adding 4.7%, 9.4%, 14.1% and 18.8% of Japanese apricot flesh to basic formulation. The compositions of Japanese apricot flesh were 88.19% moisture, 0.45% crude ash, 4.10% dietary fiber, 4.04% citric acid and 0.41% total sugars. The specific loaf volume of the breads was decreased from 3.274mL/g to 1.857mL/g as Japanese apricot flesh contents increased from 0% to 18.8%. The pH of the breads decreased but the acidity of those increased as the percentage of Japanese apricot flesh to wheat flour increased. Lightness(L value) of the breads decreased by the addition of Japanese apricot flesh, while yellowness(b value) and redness(a value) increased. Texture measurement showed that springiness, cohesiveness and resilience decreased with increase of Japanese apricot flesh contents. While, hardness, gumminess and chewiness were the lowest in the bread with 9.4% Japanese apricot flesh, and increased in the bread with 4.7%, 14.1% and 18.8% Japanese apricot flesh contents. In sensory evaluation, the highest sensory scores for flavor, taste, aftertaste and overall acceptability were obtained when Japanese apricot flesh content was 4.7%, and softness and chewiness was the best when 9.4% of Japanese apricot flesh was added. The moisture content of the breads containing Japanese apricot flesh was higher than that of the control to add no flesh during storage at $25^{\circ}C$. Based on physical, rheological and sensory evaluation, addition of 4.7{\sim}9.4% Japanese apricot flesh suggested to be acceptable for processing bread.

• Polymer(Korea)
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• v.30 no.2
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• pp.118-123
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• 2006

The effect of transesterification on the rheological properties in the melt reactive blending of poly(butylene terephthalate)(PBT) with poly(ethylene terephthalate)(PET) has been studied. The melt viscosity depression in PBT was found in PBT/PET blends due to the intrinsic low melt viscosity of PET compared to PBT. In addition, the thermal degradation in the melt blending and transesterification between two polyesters were considered as other factors fer the lowering of the melt viscosity in the blends. In the PBT/PET blends, calcium stearate was less effective than in PBT as a lubricant, however it accelerated both the thermal degradation and transesterification during melt blending. As a result, further melt viscosity drop was obtained in the reactive melt blending of PBT/PET.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.121-125
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• 2021

Very low methoxyl pectin (VLMP) has different physical and rheological properties compared to high and low methoxyl pectins (HMP and LMP). In this study, we produced LMP and VLMP by alkaline de-esterification, and investigated the structural and textural properties. Apple peel pectin was kept at pH 12 using 5.0 M NaOH solution for 3 and 24 h to produce LMP and VLMP, respectively. The molecular weight was decreased due to the removal of an esterified group in the pectin backbones by the alkali treatment, and the VLMP showed a higher calcium ion sensitivity which leads to the production of the gel with increased hardness. The result clearly showed that VLMP has the potential to improve the texture and stability in food products depending on their degree of esterification, and this result can be applied as a functional ingredient in food industrial area application to enhance the current commercial pectins.

• Food Science of Animal Resources
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• v.39 no.4
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• pp.576-584
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• 2019

This study was performed to evaluate the physicochemical properties of myofibrillar protein (MP) gels containing pork skin gelatin at different salt concentrations. MP gels were prepared to the different salt levels (0.15, 0.30, and 0.45 M) with or without 1.0% of pork skin gelatin. Cooking yield (CY), gel strength, shear stress were measured to determine the physical properties, and SDS-polyacrylamide gel electrophoresis, scanning electron microscopy, fourier transform infrared spectroscopy, sulfhydryl group and protein surface hydrophobicity was performed to figure out the structural changes among the proteins. The addition of gelatin into MP increased CYs and shear stress. MP at 0.45 M salt level had the highest CY and shear stress, as compared to MPs at lower salt concentrations. As the salt concentration of MP gels increased, the microstructure became the compact and wet structures, and decreased the amount of ${\alpha}-helix$/unordered structures and ${\beta}-sheet$. MP with gelatin showed a decreased amount of ${\alpha}-helix$/unordered structures and ${\beta}-sheet$ compared to MP without gelatin. The addition of gelatin to MP did not affect the sulfhydryl group, but the sulfhydryl group decreased as increased salt levels. MP mixtures containing gelatin showed a higher hydrophobicity value than those without gelatin, regardless of salt concentration. Based on these results, the addition of gelatin increased viscosity of raw meat batter and CY of MP gels for the application to low salt meat products.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.106-110
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• 2021

Recently, research using waste among eco-friendly materials has been attracting attention. In this study, we investigated the physical properties of blends in which high density polyethylene (HDPE) was filled with waste gypsum (CaSO₄) generated during fertilizer manufacturing. Composites were prepared by adding the gypsum content 0~20 wt% using a twin screw extruder. The mechanical, rheological, and thermal properties of the composites were evaluated. It was found that the tensile strength of the composites was less than 4.1% compared to that of unfilled HDPE, so there is no significant deterioration in physical properties. The thermal stability of the composites was improved as the gypsum content increased and the gypsum content had little effect on the viscosities of the composites.

• Elastomers and Composites
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• v.38 no.1
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• pp.57-64
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• 2003

Metal oxide(MgO) was added to FKM rubber in order to develop automotive fuel hose which ran show elastic characteristics under extreme condition. Cure characteristics, physical properties, thermal resistance and fuel resistance of FKM compounded rubber with MgO were investigated. MgO was mixed to FKM rubber materials within the range of $0{\sim}20phr$. From the test results of rheological properties and Mooney viscosity, the $t_{s2}$, $T_{c90}$ values increased as the MgO contents increased in FKM rubber compounding. Hardness and 100% modulus of FKM compounded rubber slightly increased, but tensile strength and elongations at break slightly decreased. From the test results of thermal resistance of rubber specimens at 130, 150, and $170^{\circ}C$ for 70 hrs, the changing rate of physical properties was found to be relatively small. Fuel resistance tests were carried out for fuel A, B, C and D at $40^{\circ}C$ for 70hrs, and the results showed that the changing rate in physical properties was found to increase from Fuel A to D, Furthermore thermal properties of FKM compounded rubber containing MgO were also investigated by using TGA/DSC. The optimum mixing ratio of additive to FKM rubber to get the maximum effect on thermal resistance and fuel resistance, within the range of desirable specification for rubber material, was determined to be 6 phr for MgO.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.7-12
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• 2012

Extrusion is one of the most important operations in the polymer-processing industry. Development of models for extrusion and computer tools offer a route to developing reliable and optimized process designs. The models are based on the analysis of physical phenomena encountered during the process. Balance equations for mass, momentum and energy are fundamental to the problem. A predictive computer model has been developed for the single screw extruders with conventional screws of different geometry. The model takes into account melting zones of the extruder and describes an operation of the extruder system, making it possible to predict mass flow rate of the polymer, pressure and velocity profiles along the extruder screw channel. The simulation parameters are the material and rheological properties of the polymer; the screw pitch, and screw speed.

• Elastomers and Composites
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• v.39 no.4
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• pp.263-273
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• 2004

The effects of zinc surfactant (ZB) on the bis(triethoxysilylpropyl)disulfide (TESPD)-silica mixture in natural rubber (NR) and solution butadiene-co-styrene rubber(S-SBR) were compared with respect to their rheological property, processability, physical properties, and silica dispersion. In the NR compound, addition of the ZB increased the reversion resistance time (T-2), the tensile modulus, and the BO time; however, lowered the viscosity, the HBU, and tans values. In the S-SBR copound, addition of the ZB increased the $tan{\delta}$ values while lowered the T-2, the tensile modulus the BO time, the viscosity, and the HBU of the compound. In the NR compounds, addition of the ZB significantly increased the processability and mechanical property. However, in the S-SBR compounds, it improved the processability the mechanical property was not improved.

• Computers and Concrete
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• v.25 no.1
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• pp.59-65
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• 2020

The premise for the study reflected in this article is the need to dispose of industrial waste, which is increasingly being used in the construction materials industry. Also, dynamically developing building industry demands attention of scientists and a direction of their works on improvement of the technology of carrying out construction works. Thus, the article is devoted to studying the influence of various chemical additives and fine fillers (industrial wastes) available in Kazakhstan on self-compacting concrete (SCC) mixtures and its rheological, physical, and technical properties. According to the studies, revealed the most efficient type of fine-dispersed filler and the most optimal type of chemical additive to enable obtaining a high-quality SCC mixture based on local raw materials. As a result, the use of microsilica in comparison with other industrial wastes resulted in a conglomerate with high compressive strength of SCC at early terms of curing. In terms of economic efficiency and quality improvement, the results of study are of practical value for the manufacturers of ready-mixed concrete operating in Kazakhstan.