• The Korean Journal of Rheology
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• v.8 no.2
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• pp.119-128
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• 1996

폴리프로필렌(PP)/폴리카보네이트(PC) 블렌드의 유변학적 고찰을 통해 블렌드의 수 축현상과 분상상의 변형의 연관성을 연구했다. 블렌드의 수축현상은 압축과정에서 변형됐던 분산상이 고온에서 다시 원래의 무변형 상태로 복귀하면서 나타나는 탄성변형의 풀림으로 추정되고 압출팽윤의 데이터와도 부합된다. 압출온도를 최대한 낮게 해서(25$0^{\circ}C$) 제조한 블 렌드의 경우가 최대한 높게 한 경우 (29$0^{\circ}C$)보다 수축이더 큰 사실을 설명하기 위하여 순수 PC와 PP의 전단점도비와 신장점도비를 측정 비교한 결과 두 값이 공히 높은 온도의 경우 가 오히려 작게 되어 점성에 의한 분산상의 전단변형이나 신장변형이 수축의 원인이 아니라 는 것을 알아다. 한편 법선응력과 전단응력의 데이터로부터 얻은 물질풀림시간의 비는 낮은 온도의 경우가 작아서 수축현상이 분산상의 탄성에 의한 변형이라는 것을 확인했다.

• Bulletin of Food Technology
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• v.4 no.4
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• pp.35-40
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• 1991

• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.189-194
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• 1983

Raw and extruded barleys prepared by three different conditions were powdered and stored for four months at ambient $(25^{\circ}C)$ and accelerated temperatures $(40^{\circ}C)$ with $A_w$ of 0.31 and 0.71, respectively. The stability of the these samples with respect to lipid oxidation was studied. The lipid oxidation of all samples, as measured by the lipid diene conjugation of the extracted oil, increased with increased $A_w$ and temperature and with the storage time elapsed. The ratio of unsaturated to saturated fatty acids (U/S ratio) tended to decreased as the $A_w$ and temperature were increased. The raw sample had a greater increase in lipid conjugation diene but a decrease in U/S ratio than the extruded samples. The extruded sample containing the added sucrose had greater lipid stability than the other extruded samples. Lipid free-amino group content in all samples decreased with increased $A_w$ and temperature.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.287-294
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• 1983

Change of color, browning index, soluble protein, reducing sugar content, and available lysine were monitored for raw and extruded barely powders during four months of ambient and accelerated storage temperatures with $A_w$ of 0.31 and 0.71, respectively. Loss of whiteness and soluble browning pigments increased with increased $A_w$ and temperature. The raw sample had an increased rate of browning intensity than the extruded samples. Among the extruded samples, the added sucrose sample had the lowest rate of browning during storage. Loss of reducing sugar content in all samples increased with increased $A_w$ and temperature. The loss of soluble protein and of the available lysine also increased with increased $A_w$ and temperature. The loss of reducing sugar and of the available lysine was at least partly due to the Maillard browning reaction. These results have important implications in teh processing and storage of raw and extruded burleys.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1068-1075
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• 2012

Poly(butylene terephthalate) (PBT)/Nylon6,12 core/shell micro fiber were prepared by extrusion molding. To investigate their optimum extrusion conditions, compatibility of PBT/Nylon6,12 blend micro fiber in conformity to their weight ratio and manufacture temperature was explored with SEM morphology and DSC. The alterations in their mechanical properties by extrusion speed were compared and analyzed through a UTM. In comparison with SEM figures, the domain sizes of Nylon6,12 were gradually declined by increasing the extrusion temperature of blends. Furthermore, according to these SEM images, the phase separation between Nylon6,12 domain and PBT matrix became indistinct with increasing of weight percentage of Nylon6,12. In case of DSC, the boundaries of two peaks were almost disappeared when increasing the extrusion temperature and also intervals of each two melting peaks became narrow as increasing the Nylon6,12 ratio. The mechanical properties including tensile strength, elongation, flexural strength and flexural modulus were increased as the increase in the extrusion temperature until $260^{\circ}C$. However, the mechanical properties were actually deteriorated over $260^{\circ}C$. The tensile strength, elongation, flexural strength and flexural modulus at $260^{\circ}C$ were 560 $kg_f/cm^2$, 220%, 807 $kg_f/cm^2$ and 22,146 $kg_f/cm^2$, respectively. These values are more than intermediate values of mechanical properties of PBT and Nylon6,12. These results mean that there is compatibility between PBT and Nylon6,12. Based on the extrusion conditions that produced optimum compatibility of blend, as a result, our group obtained micro fibers with the core/shell structure.

• Clean Technology
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• v.4 no.2
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• pp.32-40
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• 1998

The polymeric porous materials which consist of polypropylene(PP) and polyethylene(PE) powder were prepared to apply to the air purification systems by extrusion sintering method. SEM analysis showed that a composite polymeric porous structure made up of PP and PE was obtained, where PE was melted and adhered to PP because the melting temperature of PE was lower than that of PP. The filtration characteristics and mechanical properties of polymeric porous materials were investigated by varying the head die temperature of the extruder, extrusion velocity, and the melt index and quantity of PE. The filtration efficiency was proportional to the quantity of PE but inversely proportional to the melt index of PE. The polymeric porous materials composed of PP and PE, which was made by extrusion sintering method, was found to be suitable for the filter element of the air purification system.

• Korean Journal of Food Science and Technology
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• v.23 no.1
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• pp.81-87
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• 1991

To examine the effect of the individual operational variables on extrusion process, test trials of the fractional factorial design of the three process variables at three levels, including feed rate, screw speed and die openings, were carried out by using a laboratory scale twin-screw extruder with three different screw configuration for corn grit with the water addition fixed at 15% of the powder feed rate. As the increase of feed rate, while extrusion temperature(ET), specific mechanical energy input (SME), and residence time(RT) were showed the tendency to decrease, extrusion pressure(EP) was increased and as the increase of screw speed, ET, SME and EP were showed the tendency to increase, but RT was decreased. However, as increase the number of die hole, all system parameters were showed the tendency to decrease. The influence of the change in each process parameters was increased as the increase of the number of reverse element in screw configuration. In case of using the screw configuration with increasing number of reverse element at the condition of same process parameters, ET, SME and RT was increased, but EP was decreased. The functional relationships of the system parameters to the process parameters can be quantified by using multiple regression equations(mostly R-sq>0.90) and maped on suface response diagrams to expedite evaluation.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.444-452
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• 2017

This study aims to investigate the physicochemical properties of the extruded rice snack with added the containing mealworm. Adding the mealworm addition enhanced protein and unsaturated fatty acid contents, which are insufficient in rice. As the extrusion process variables, the death temperatures and moisture content were set to at respective 130 and $140^{\circ}C$, and 20 and 25%, respectively. The expansion ratio increased as with death temperature, whereas the increased moisture content decreased. The nitrogen solubility index and protein digestibility index increased with the added mealworm content of mealworm increased. As mealworm content and death temperature, and moisture content increased, DPPH radical scavenging activity significantly increased but the rancidity decreased. As the result of this study, confirmed that the addition of mealworm to the extruded rice snack was the confirmed as the effective process to improve nutrition, and antioxidation. Also, death temperature and moisture content have an effect on softened the texture of extruded rice snack.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.945-951
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• 1994

In order to elucidate the extrusion characteristics of $SiC_{p}$/6061 Al composite, defomation resistance, $K_{w}$ was determined using the empirical formula suggested by Watanabe et al, and also extrusion pressure was measured using the extrusion press with a capacity of 350 ton. The $K_{w}$ which are propotional to extrudability, was increased with increasing volume fraction of reinforcement, $SiC_{p}$, but decreased with increasing the particle size. The peaks of maximum extrusion pressure in curves of extrusion force vs ram stroke were changed sharply with decreasing the particle size. The elevated extrustion temperature resulted in the decreased $K_{w}$ and extrusion pressure, but caused the surface tearing of extrusion composite bars. The results showed that extrudability of the composite billets is depend on the extrusion conditions as well as the characteristics of reinforcement, $SiC_{p}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.3
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• pp.380-385
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• 2016

This study analyzed changes in ${\beta}$-glucan content in Agaricus blazei Murill concentrates according to extrusion and extraction conditions. Screw speed and feed rate were fixed to 250 rpm, and 100 g/min, respectively. Moisture contents (20 and 30%) and barrel temperature (130 and $140^{\circ}C$) were adjusted. ${\beta}$-Glucan content of the extruded sample at a moisture content of 20% and barrel temperature of $130^{\circ}C$ was higher compared to other extrusion conditions. ${\beta}$-Glucan content of the extruded sample at a moisture content of 20% and barrel temperature of $130^{\circ}C$ treated with Rohament CL enzyme was higher compared to Viscozyme L, and Plantase TL enzyme treatments under the same extrusion conditions. In conclusion, extrusion and pretreatment with Rohament CL enzyme enhanced yield of ${\beta}$-glucan extract.