• Elastomers and Composites
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• v.31 no.4
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• pp.292-297
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• 1996

• Elastomers and Composites
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• v.30 no.1
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• pp.42-49
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• 1995

• Journal of the Korean Society for Precision Engineering
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• v.24 no.2 s.191
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• pp.41-46
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• 2007

Recently, the study for filling imbalance in thermoplastic polymer has gradually been increased. However, it is hard to find the researches for filling imbalance of thermoplastic elastomer(TPE). The experiment of filling imbalance was conducted for the three kinds of thermoplastic vulcanizes(TPVs) in the mold with geometrically balanced runner system. In this experiment, the effects of the melt temperature and injection speed on the filling imbalance were investigated. To solve the filling imbalance, Runner Core pin(RC pin) in the experimental mold was adopted and it's effects was tested. In this paper, we present that the insert length of RC pin is dependent to each polymers for optimal filling balance.

• Elastomers and Composites
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• v.50 no.4
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• pp.245-250
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• 2015

Recycling of ethylene-propylene-diene terpolymer (EPDM) scrap was tried by blending with polypropylene (PP). EPDM scrap powder was prepared by shear pulverization process at high temperature, which may lead to selective chain scission induced by difference in the critical elastic coefficient. On the other hand, EPDM scrap powder was prepared by adding a selected reclaiming agent during shear pulverization process at high temperature. Terpene as a bonding agent was then introduced to improve adhesion property. PP, used as a matrix for manufacturing thermoplastic elastomer, was modified by the incorporation of dicumyl peroxide and maleic anhydride. The functionalized EPDM and modified PP were blended and cured dynamically at $190^{\circ}C$. The blend materials prepared in this study showed the comparable results to those of conventional TPE in terms of tensile and flow properties. Also, the odor component of recycled EPDM was analyzed using GC-MS.

• Rubber Technology
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• v.1 no.1
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• pp.87-94
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• 2000

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.103-111
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• 2015

Objective : The purpose of this study was to evaluate the effect for running shoes with resilience of midsole on biomechanical properties. Methods : 10 healthy males who had no history of injury in the lower extremity with an average age of 26.5 year(SD=1.84), height of 172.22 cm(SD=4.44) and weight of 67.51 kg(SD=6.17) participated in this study. All subjects ran on the treadmill wearing three different running shoes. Foot pressure data was collected using Pedar-X system(Novel Gmbh, Germany) operating at 100 Hz. Surface EMG signals for biceps femoris, rectus femoris, vastus lateralis, medial lateralis, tibialis anterior, medial gastrocnemius, soleus and peroneus longus were acquired at 1000 Hz using Bignoli 8 System(Delsys Inc., USA). To normalize the difference of the magnitude of muscle contractions, it was expressed as a percentage relative to the maximum voluntary contraction (MVC). The impact resilience of the midsole data was collected using Fastcam SA5 system(Photron Inc., USA). Collected data was analyzed using One-way ANOVA in order to investigate the effects of each running shoes. Results : TPU midsole was significantly wider in contact area than EVA, TPE midsole in midfoot and higher in EMG activity than EVA midsole at biceps femoris. TPE midsole was significantly wider in contact area than EVA midsole in rearfoot and higher in peak pressure than EVA midsole in forefoot. EVA midsole was significantly higher in EMG activity than TPU midsole at tibia anterior. In medial resilience of midsoles, TPE midsole was significantly higher than EVA, TPU midsole. Conclusion : TPU midsole can reduce the load on the midfoot effectively and activate tibialis anterior, biceps femoris to give help to running.

• Polymer(Korea)
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• v.37 no.5
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• pp.571-578
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• 2013

Polyamide12 (PA12) is blended with ethylene propylene diene rubber (EPDM) at various compositions in the presence of maleated EPDM (mEPDM) to afford blend materials having the characteristics of thermoplastic elastomer (TPE). The EPDM/PA12 melt-blends are further irradiated with electron-beam (e-beam) at 0~100 kGy dosage, yielding selective crosslinking between EPDM chains while retaining melt-processibility originated from PA12 phase. mEPDM acts as a compatibilizer and affords additional improvements in mechanical properties of the EPDM/PA12 blend. With 25 kGy of e-beam irradiation and mEPDM, the EPDM/PA12 blends successfully exhibit TPE behaviors with reasonable elastomeric and mechanical properties.

• Elastomers and Composites
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• v.48 no.1
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• pp.24-29
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• 2013

We have developed the synthetic processes for the monomers of polyamide-type TPEs (thermoplastic elastomers, TPAEs) obtained from vegetable oil. TPAEs have several superior physical properties to those of thermoplastic elastomers (TPEs). From the common starting material, oleic acid, which is commonly found in various vegetable oils, we have synthesized three ${\omega}$-amino acid monomers ($C_9$, $C_{10}$ and $C_{11}$ ${\omega}$-amino acid) and three ${\alpha}$, ${\omega}$-dicarboxylic acids($C_9$, $C_{10}$ and $C_{11}$ ${\alpha}$, ${\omega}$-dicarboxylic acid) for TPAEs in good yields.

• Tuberculosis and Respiratory Diseases
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• v.42 no.4
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• pp.455-464
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• 1995

Background: Considering that both humoral and cell mediated immunities play an important role for human tuberculosis infection, enzyme-linked immunosorbent assay(ELISA) measurement of immunoglobulin G (IgG) antibody to mycobacterial antigens can be used for the serologic diagnosis of tuberculous pleural effusion. Method: We measured absorbance values of IgG antibodies to purified-protein-derivative (PPD) and lipoarabinomannan-B (LAM-B) in the pleural fluid (PF) and the serum in 40 tuberculous (TPE) and 19 nontuberculous pleural effusions (NTPE). Results: 1) The IgG antibodies to PPD and LAM-B were significantly (P<0.0005) higher in the PF and the serum of TPE compared to NTPE. 2) The IgG antibodies to PPD and LAM-B in the serum were higher than that in PF. 3) Significant correlations were found between pleural and serum IgG antibodies to PPD and LAM-B. 4) With a cutoff value for IgG antibody to PPD in the PF of 0.091, sensitivity was 55.0% and specificity 94.7% in the diagnosis of TPE. 5) With a cutoff value for IgG antibody to LAM-B in the PF of 0.337, sensitivity was 50.0% and specificity 94.7% in the diagnosis of TPE. 6) The seropositive rates in TPE were not related to PPD skin test status, the amount of PF and coexisting active pulmonary tuberculosis. Conclusion: The assay of IgG antibodies to PPD and LAM-B might be useful for the diagnosis of TPE. Our study suggests the mechanism of passive transfer of IgG antibodies to PPD and LAM-B from the serum to the PF through pleural tissue.

• Tuberculosis and Respiratory Diseases
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• v.80 no.1
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• pp.77-82
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• 2017

Background: Delayed hypersensitivity plays a large role in the pathogenesis of tuberculous pleural effusion (TPE). Macrophages infected with live Mycobacterium tuberculosis (MTB) increase the levels of adenosine deaminase2 (ADA2) in the pleural fluid of TPE patients. However, it is as yet unclear whether ADA2 can be produced by macrophages when challenged with MTB antigens alone. This study therefore evaluated the levels of ADA2 mRNA expression, using monocyte-derived macrophages (MDMs) stimulated with MTB antigens. Methods: Purified monocytes from the peripheral blood mononuclear cells of healthy volunteers were differentiated into macrophages using granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF). The MDMs were stimulated with early secretory antigenic target protein 6 (ESAT6) and culture filtrate protein 10 (CFP10). The mRNA expression levels for the cat eye syndrome chromosome region, candidate 1 (CECR1) gene encoding ADA2 were then measured. Results: CECR1 mRNA expression levels were significantly higher in MDMs stimulated with ESAT6 and CFP10, than in the unstimulated MDMs. When stimulated with ESAT6, M-CSF-treated MDMs showed more pronounced CECR1 mRNA expression than GM-CSF-treated MDMs. Interferon-${\gamma}$ decreased the ESAT6- and CFP10-induced CECR1 mRNA expression in MDMs. CECR1 mRNA expression levels were positively correlated with mRNA expression of tumor necrosis factor ${\alpha}$ and interleukin 10, respectively. Conclusion: ADA2 mRNA expression increased when MDMs were stimulated with MTB antigens alone. This partly indicates that pleural fluid ADA levels could increase in patients with culture-negative TPE. Our results may be helpful in improving the understanding of TPE pathogenesis.