• The Korean Journal of Rheology
• /
• v.11 no.2
• /
• pp.159-167
• /
• 1999

Sandwich injection molding is one of the remarkable polymer processes recently developed from conventional injection molding. But it is almost impossible to do theoretical investigation that we've researched it through numerical simulation. In this paper, numerical simulation on the study of sandwich injection molding is based on Finite Element Method and FAN/Control Volume method. In addition to conventional filling parameter that can confirm skin polymer melt front, new filling parameters have been introduced to confirm core polymer melt front advancement. These filling parameters are defined in each layer which is divided to solve temperature field along the thickness direction. One can notice different filling patterns resulted from the variation of material properties such as viscosities and power-law indexes, and processing conditions such as switch-over times and wall temperatures. It gives us a better understanding of the sandwich injection molding process. And we can recognize that it's the core polymer spatial distribution after the completion of filling that is the most important key point to use this process for industrial molding process.

• Journal of ILASS-Korea
• /
• v.1 no.3
• /
• pp.20-28
• /
• 1996

It is well known that drag reduction in single phase liquid flow is affected by polymer material, molecular weight, polymer concentration, pipe diameter, and flow velocity. Drag reduction in two phase flow can be applied to the transport of crude oil, phase change system such as chemical reactor, pool and boiling flow, and to present cavitation which occurs in pump impellers. But the research of drag reduction in two phase flow is not sufficient. The purpose of the present work is to evaluate the drag reduction by measuring pressure drop, void fraction whether polymer is added in the horizontal two phase system or not. Experiment has been conducted in a test section with 24 m of the inner diameter and 1,500 mm of the length. The used polymer materials are two kinds of polyacrylamide[PAAM] and co-polymer[A611P]. The polymer concentration was varied with 50, 100 and 200 ppm under the same experimental conditions. Experimental results were shown that the drag is higher reduced by co-polymer rather than polyanylamide.

• Proceedings of the KIEE Conference
• /
• 1998.11c
• /
• pp.822-824
• /
• 1998

The lithium polymer battery with polymer electrolyte is expected as a safe and long cycle life battery. This paper reports primarily the recent development results of a solid polymer electrolyte, which is a key point of the secondary battery system. The new type of polymer electrolyte was prepared under a dry Ar atmosphere by dissolving $LiCIO_4$ in a matrix of EC, PC and then dispersing polyacrylonitrile(PAN). Also adding some inorganic filler $Al_2O_3$. The dispersed solution heated at $120^{\circ}C$. The polymer electrolyte were characterized by EIS(Electrochemical Impedance Spectroscopy), TGA(Thermo Gravimetric analysis), DMA(Dynamic Mechanical Analyzer), DSC (Differential Scanning Calorimetry). The lithium ion yield is 0.29 when PAN-$Al_2O_3$ which was applied DC 5mV. The ionic conductivity of PAN, PAN-$Al_2O_3$ polymer electrolytes were showed $1.0{\times}10^{-4}S/cm$, $8.4{\times}10^{-4}S/cm$ at room temperature. When inorganic filler was added in the polymer electrolyte, ionic conductivity and lithium yield more larger than without inorganic filler.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.50 no.5
• /
• pp.19-27
• /
• 2008

This study was performed to evaluate the compressive strength and acid-resistant of polymer concrete using redispersible polymer powder(RPP) and blast furnace slag powder(BSP). Material used were ordinary portlant cement, recycled coarse aggregate, natural fine aggregate, redispersible polymer powder and blast furnace slag powder. The main experimental variables were the substitution ratio of redispersible polymer powder and blast furnace slag powder, when the substitution ratios of RPP were 0, 1, 2, 3, 4, 5 and 6%, and those of BSP were 10%. The compressive strength and acid-resistant of polymer concrete using RPP and BSP were compared with those of ordinary concrete(Basis). When the substitution ratio of RPP was 1%, at age of 28 days, the compressive strength were more higher than those of Basis by 24%, and it was decreased with increasing the RPP content, respectively. Also, the water absorption ratio was decreased with increasing the RPP content. But, the acid-resistant was improved with increasing the RPP content.

• Journal of Electrochemical Science and Technology
• /
• v.2 no.1
• /
• pp.26-31
• /
• 2011

We have prepared siloxane polymers grafted with trifluoromethane-sulfonylamide and oligoether side chains for solid polymer electrolytes with enhanced ionic conductivity. The grafted trifluoromethane sulfonylamide groups seem to be effective as an anion recepting site to enhance the ionic conductivity of the solid polymer electrolyte. The anion receptor grafted siloxane polymers showed one order of magnitude higher ionic conductivity than the siloxane polymers without anion receptor grafts. The fitting parameter A of the VTF plot which was related to the carrier density of the electrolyte increased with increasing the number of grafted anion receptor. The results of experiment indicate that the anion-complexing site of the anion receptor grafted polymer host effectively traps the anions. The anion receptor grafted polymer was found to be a promising material for lithium polymer batteries.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.20 no.8
• /
• pp.18-24
• /
• 2021

Polymers, polymer compounds, are very moldable at low temperatures and have good strength against weight, and hence, are often used in the interior and exterior materials of cars. Owing to the increasing environmental problems, emission regulations have become stricter, which has increased the use of lightweight polymers as substitutes for metal materials. Therefore, as the use of polymer increases, extensive research is being conducted on the bonding technology of polymers, such as polyurethane and epoxy. However, the increased cost and environmental pollution by adhesives caused by the polymer manufacturing plant depend on the chemical composition or the manufacturer's mix ratio. To compensate for this issue, a laser beam is irradiated through a highly permeable polymer (PC) placed on top of an absorbent polymer (ABS) to transfer the laser output to the ABS polymer and fuse them at the interface. Moreover, enabling laser penetrating bonding by placing a stainless steel wire mesh between the two polymers can achieve improved bonding strength compared to conventional heterogeneous polymer bonding.

• Journal of the Korea Convergence Society
• /
• v.13 no.4
• /
• pp.331-337
• /
• 2022

Manufactured thermoplastic composite materials to replace the metal materials used as battery housing materials for electric vehicles with lightweight materials. As the matrix material, nylon 6 which is a polymer material was used. Boron Nitrate(BN), which has high thermal conductivity, was used to provide heat dissipation performance. The heat dissipation characteristics of the thermally conductive polymer composite material according to the BN content and particle size were analyzed. The thermal conductivity value increased as the filler content increased, and composite materials particle size of 60 to 70㎛ and BN content of 50%, the thermal conductivity was 1.4 W/mK. The larger the particle size, the wider the inter-particle interface contact surface, which means that a thermal path was formed. wider the interfacial contact surface between the particles, and the thermal path was formed. A battery housing was manufactured using the manufactured thermally conductive polymer composite material, and the temperature change during charging and discharging of the cell was observed, and the possibility as a substitute material for the battery housing was confirmed.

• Proceedings of the KIEE Conference
• /
• 1999.07d
• /
• pp.1538-1540
• /
• 1999

For the development of electro magnetic shielding materials by use of the conductive polymer, measuring technique related to their shielding effect should be well established. For this propose, several commercialized techniques based on different conception have been well compared in order to adopt appropriate method to our materials under development and then, flanged coaxial holder type fixture device has been fabricated and tested satisfied performance has been obtained showing over 90dB in dynamic range with accuracy of +/-2dB.

• Polymer(Korea)
• /
• v.29 no.3
• /
• pp.237-241
• /
• 2005

Photocurable pentaerythritol modified hyperbranched acrylates were prepared from trimellitic anhydride, glycidyl methacrylate and pentaerythritol derivatives. Thermal stability obtained by using TGA showed that HBMA-1 was superior to the others. Hardness, abrasion resistance and tensile strength of HBMA-1 showed that Hey were also superior to the others. Value of yellow index of HBMA-1 showed the lowest.

• Journal of the Korean Ceramic Society
• /
• v.31 no.9
• /
• pp.941-948
• /
• 1994

An underwater grout on material resistance against segregation in water were studied by water soluble polymer (methyl cellulose and acrylic acid ester and styrene). The mechanical properties of the grout agents were investigated through the observation of the microstructure and application of fracture mechanic. When the soluble polymer MC+AAES added with 0.6 wt% to the underwater grout agents the compressive strength, flexural strength and Young's modulus were about 58 MPa, 10 MPa and 3.2 GPa respectively, and critical stress intensity was about 0.8 MNm-1.5. It can be considered that the strength improvement and fracture toughness increase may be due to the pore decrease and bonding force by material resistance against segregation in water.