• Elastomers and Composites
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• v.38 no.4
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• pp.342-353
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• 2003

This work is about the development of jet-fuel resistant PVC sealant using a polyester plasticizer. PVC copolymer was compounded with adipic acid glycol(Songcizer P-3000) or DOP plasticizers. Fuel-immersed and non-immersed penetration, solubility, flow, and elongation by tensile adhesion of PVC compounds were measured. Penetration increase by fuel immersion and solubility of PVC compounds with adipic acid glycol polyester plasticizer were smaller than those of PVC compounds with DOP plasticizer. Elongation by tensile adhesion test of PVC compound containing 500 phr of Songcizer P-3000 decreased proportionally to the content of DCDP (dicyclopentadiene) base petroleum resin adhesion promoter. Calcium carbonate($CaCO_3$) filler inhibited the diffusion of fuel in all the PVC compounds and decreased the solubility of PVC compounds containing Songcizer P-3000.

• Elastomers and Composites
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• v.48 no.2
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• pp.125-132
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• 2013

In this work, we have discussed new engineering systems for preparing carbon master batch composed by carbon black and various organic compounds. In general, polymer resin, which applied for automobile tire, household items, and various industry items, is used with the fillers including carbon black and silica to control the color or properties. Domestic part and material industry has been remarkably developed in that the development of materials including the compounding of raw materials. Meanwhile, the engineering technique for mass production has not reached to a requirement of industry due to slow technique development and high dependence on foreign. Thus, we will focus on the introduction of new engineering technique developed by domestic company for preparing carbon master batch.

• Elastomers and Composites
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• v.36 no.2
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• pp.94-101
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• 2001

In this work, the effect of NE plasma treatment generated by radio-frequency was investigated in acid-base surface values, ion adsorption characteristics, and surface free energies of carbon blacks. As the results, it was clearly found that the obvious improvement of the treatment is in the London dispersive component (${\gamma}s^L$) of surface free energy of carbon blacks. Also both electron-acceptor ( ${\gamma}s^+$) and -donor (${\gamma}s^-$) parameters for the specific component (${\gamma}s^{sp}$) were also increased with increasing the treatment time, resulting in increasing the surface functional groups of the carbon blacks studied, together with a consequence of the increases of acidic and basic surface functional groups, ion exchange, zeta potential, and ion mobility.

• Elastomers and Composites
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• v.53 no.3
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• pp.158-167
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• 2018

In this study, in-situ trans-selective polymerization of isoprene was carried out using titanium-based Ziegler-Natta catalysts. The catalysts were prepared by high-energy ball milling. Individually Large-inner-diameter carbon nanotubes (CNTL), and hydroxylated carbon nanotubes (CNTOH), along with magnesium chloride ($MgCl_2$) were used as the carriers for the catalysts. The optimum ball-milling time for preparing the $CNT/MgCl_2/TiCl_4$ Ziegler-Natta catalysts was 4 h. The $CNTOH/MgCl_2/TiCl_4$ catalyst showed a higher efficiency than that of the $CNTL/MgCl_2/TiCl_4$ catalyst, based on the rate of polymerization. The effects of the CNT-filler type on the isoprene polymerization behaviors and polymer properties were investigated. The morphologies of the trans-1,4-polyisoprene (TPI)/CNT and TPI/CNTOH nanocomposites exhibited a tube-like shape, and the CNTL and CNTOH fillers were well dispersed in the TPI matrix. In addition, the thermal stability of TPI significantly increased upon the introduction of a small amount of both CNTL/CNTOH fillers (0.15 wt%), owing to the satisfactory dispersion of the CNTL/CNTOH in the TPI matrix.

• Polymer(Korea)
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• v.27 no.1
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• pp.40-45
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• 2003

In this work, the effect of different contents of $Fe_3O_4$ and temperature variation on the electrical conductivity ($\sigma$) in the polar acrylonitrile butadiene rubber (NBR)/$Fe_3O_4$ (magnetite) mixture system was investigated. It was found that the percolation threshold concept holds true for the conductive particle-filled composites where $\sigma$ indicates a nearly sharp increase when the concentration of magnetite in the mixture exceeds 22%. The temperature dependence of $\sigma$ was thermally activated below and at the percolation threshold ($P_c$). Magnetite acted as reinforcing and conductive filler for NBR. At room temperature and higher voltages, the electrical current was proportional to the square of voltage ($I{\propto}V^2$) for the composites which contain 30 phr of magnetite. Moreover, it was shown that the composites with magnetite of 50 phr showed the highest tensile strength and elongation at break, which was due to the formation of optimal physical interlock and crosslinking. The results of 100%, 200%, and 300% Young moduli said that the moduli are largely correlated with reinforcement effect of magnetite and viscosity of the blends from torque curve.

• Elastomers and Composites
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• v.45 no.1
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• pp.32-39
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• 2010

The mechanical properties of PTFE 100%, PTFT 90% + carbon black 10%, PTFE 85% + glass fiber 15%, PTFE 80% + glass fiber 15% + molybdenum disulfide ($MoS_2$) 5%, PTFE 75% + glass fiber 25%, and PTFE 75% + carbon black 18% + graphite 7% composites were investigated in this study. The differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to examine the heat of fusion(${\Delta}H_f$) and thermal stability of the composites. Also, the wear surface and wear volume of PTFE lip seal were examined using the durability test. Wear surface was observed using scanning electron microscope (SEM). It was found that the hardness, wear resistance and durability were enhanced by adding glass fiber and molybdenum disulfide into pure PTFE, but tensile strength and elongation were decreased. According to the experimental results, the composite (PTFE + 15% glass fiber + 5% molybdenum disulfide) showed the best properties for applying to oil-seal among six types of PTFE composites.

• Elastomers and Composites
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• v.45 no.1
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• pp.12-16
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• 2010

In this work, the effect of hydrophobic treated silica on the water absorption, thermal stabilities, and mechanical properties of the epoxy nanocomposites were investigated as a function of the silica content. As filler, fumed silica treated by dimethyldichlorosilane was used. It was found that the silica was well dispersed in the epoxy resins by the melt-mixing method with the addition of a silane coupling agent. The water absorption of the nanocomposites decreased with an increase of the silica content due to the effect of hydrophobic treated silica. The thermal properties, such as thermal degradation temperature, glass transition temperature ($T_g$), and coefficient of thermal expansion (CTE), of the nanocomposites were improved by the addition of silica. Furthermore, the mechanical properties of the nanocomposites, that is, the tensile strength and modulus, were enhanced with increasing silica content. This was attributed to the physically strong interaction between silica and epoxy resins.

• Elastomers and Composites
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• v.37 no.4
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• pp.258-264
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• 2002

In this work, the influence of thermal treatment on surface properties of silicas and mechanical interfacial properties of silicas/polyurethane composites was investigated. The surface properties of thermally treated silicas were studied in the context of Fourier Transform-IR (FT-IR), solid-state 29Si NMR spectroscopy, and contact angle. And the mechanical interfacial properties of the silica/polyurethane composites were evaluated by composite tearing energy (GIIIC). As a result, it was found that the thermally treated silica surfaces became hydrophobic in nature, due to the condensation of surface hydroxyls and the formation of siloxane bonds, resulting in increasing the London dispersive component of surface free energy. From which, the increase of the London dispersive component of the silicas led to an improvement of the dispersion of silicas in a polyurethane matrix, finally resulting in improving the tearing energy (GIIIC) of the silicas/polyurethane composites.

• Elastomers and Composites
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• v.38 no.3
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• pp.213-226
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• 2003

The cure and rheological behavior of diglycidyl ether of bisphenol F/nadic methyl anhydride resin system with the kinds of imidazole were studied using a differential scanning calorimeter (DSC) and a rotational rheometer. The isothermal traces were employed to analyze cure reaction. The DGEBF/ anhydride conversion profiles showed autocatalyzed reaction characterized by maximum conversion rate at $20{\sim}40 %$ of the reaction. The rate constants ($k_1,\;k_2$) showed temperature dependance, but reaction order did not. The reaction order (m+n) was calculated to be close to 3. There are two reaction mechanisms with the kinds oi catalyst. The gel time was determined by using G'-G" crossover method, and the activation energy was obtained from this results. From measurement of rheological properties it was found that the logarithmic 1:elation time of fused silica filled DBEBF epoxy compounds linearly increased with the content of filler and decreased with temperature. The highly filled epoxy compounds showed typical pseudoplastic behavior, and the viscosity of those decreased with increasing maximum packing ratio.