• Polymer(Korea)
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• v.36 no.4
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• pp.407-412
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• 2012

The characteristics of nylon6/ionomer semi interpenetrating networks (IPN) as a molded-in-color (MIC) compound had been studied, and comparison was made with nylon6/ionomer blends. Nylon6/ionomer semi IPN shows better homogeneity in phase morphology than nylon6/ionomer blend, and it caused better anti-scratching performance than the blend. This semi IPN structure resulted in lowered crystallization rate, increased melt viscosity and less temperature dependency of viscosity. As a result, we may expect the enhancement of melt processing characteristics in an injection molding process using nylon6/ionomer semi IPN as a MIC compound.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.69-72
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• 1999

A Well oriented Bi$_2$re$_2$CaCu$_2$O$\sub$8/(Bi2212) superconductor thick films were formed successfully on a copper substrate by liquid reaction between a Cu-free precursor and Cu tape using method in which Cu-free BSCO powder mixture was printed on copper plate and heat-treated. And we examined the mechanism for the rapid formation of Bi2212 superconducting films from observing the surface microstructure with heat-treatment time. At heat-treatment temperature, the printing layer partially melt by reacting with CuO of the oxidizing copper plate, and the nonsuperconducting phases present in the melt are typically Bi-free phases and Cu-free phases. Following the partial melting, the Bi$_2$Sr$_2$CaCu$_2$O$\sub$8/ superconducting phase is formed at Bi-free phase/liquid interface by nucleation and grows. It was confirmed that the phase colony from the phase diagram of Bi$_2$O$_3$-(SrO+CaO)/2-CuO system is similar to the observed result.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.860-863
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• 2009

YBCO bulks with fine $Y_2BaCuO_5$(Y211) particles have been prepared by the top-seed modified powder melting process method, Solid-Liquid Melt Growth(SLMG), with $Y_2O_3$, $BaCuO_2$ and CuO mixing precursor. By using $Y_2O_3$ instead of $Y_2BaCuO_5$ as precursor, the processing became to be simpler and cheaper than the current powder melting process. The microstructures, trapped field and critical current density of the various conditioned YBCO bulks have been analyzed and the effect of Pt additive was studied. The different trapped magnetic field values of the several samples have been explained in the viewpoint of their microstructures. The fabrication of large-sized YBCO single domain has been conducted.

• Polymer(Korea)
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• v.30 no.3
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• pp.202-206
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• 2006

The plasticized cellulose diacetate (CDA) was prepared by melt processing methods using triacetine (TA) as a plasticizer. Additionally, processability of CDA was enhanced by using epoxidized soybean oil as a secondary plasticizer. The glass transition temperature of plasticized CDA was observed at $50^{\circ}C$ lower than virgin CDA and the incorporation of 5% ESO also resulted in the additional $20^{\circ}C$ decrease in the $T_g$. The tensile properties and modulus of plasticized CDA were better than commercial PP and PLA. The aerobic biodegradability of CDA in controlled compositing condition resulted in 90% of degradation during 60 days.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.650-654
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• 2020

A combination of Polycarbonate (PC) material and Polymethylmethacrylate (PMMA), fabricated using an injection molding machine, has been investigated to determine its advantages, as studied in Ref. 1). This paper aims to investigate the optimization of PMMA/PC blend for both tensile yield strength and impact strength. Furthermore, interaction effects of process conditions on mechanical properties including tensile yield strength and impact strength of PMMA/PC blend by injection molding process are interpreted in this study. Tensile and impact specimens are designed following ASTM, type V, and are fabricated by injection molding process. The processing conditions such as melt temperature, mold temperature, packing pressure, and cooling time are applied; each factor has three levels. As a result, in comparison with optimization of separated responses, mechanical properties of PMMA/PC are found to decrease when optimizing both tensile and impact strengths simultaneously. The melt temperature is found to be the most significant interaction parameter with the mold temperature and packing pressure. In addition, there is more interaction between the mold temperature and cooling time. This investigation provides a useful understanding of the control of injection molding processing of polymer blends in optical application.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.135-138
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• 2007

A semi-solid forming processing has been developed for manufacturing near net-shape components. The semi-solid forming has two methods. One is thixo-forming with reheating prepared billet, the other is rheo- forming with cooled melt until semi-solid state. In indirect forging processing, this experiment used aluminum rheology materials by electromagnetic stirring system. Rheology material is made by A16061. An experiment has variation factors which are pressure, solid-fraction, stirring current and stirring time. Forged samples are found microstructures and mechanical properties. Forged samples are accomplished heat treatment T6 for high mechanical properties.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.150-153
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• 2003

Microwaves belong to the portion of the electromagnetic spectrum with frequencies between 300MHz and 300GHz.$\^$1)/ In microwave processing, the energy is delivered directly to materials through molecular interaction with the electromagnetic field. This result in rapid heating throughout the material thickness with the reduced thermal gradients. If microwave is applied to fibrous materials, it can be reduced processing time. (omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.706-709
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• 2005

Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed in multi-cavity injection mold. These filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during the injection molding processing. This paper presents a solution of these filling imbalances by using runner core pin which creates a symmetrical shear distribution within runner and the effects on filling imbalance when modifying a shape of runner core pin. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed. In addition we investigated how filling imbalances were affected by shape of runner core pin.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.39-42
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• 2005

For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filling imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.13-16
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• 2005

For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filing imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.