• Polymer Science and Technology
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• v.4 no.3
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• pp.193-202
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• 1993

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.65-68
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• 2002

No Abstract, See Full Text

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.9-9
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.896-905
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• 2012

Recently, the application of the plastic material to automotive components and structures has steadily increased to satisfy demands on the saving of overall weight and the improvement of energy efficiency. The objective of this paper is to investigate the development of a bumper back-beam using a thermoplastic olefin (TPO). The bumper back-beam was designed to be manufactured from the injection molding process. In order to obtain a proper design of the bumper back-beam, three-dimensional finite element analyses were performed for various design alternatives. Stress-strain curves for different strain rates were measured by high speed tensile tests of the TPO to consider strain rate effects in the FEA. The influence of the sectional shape and the rib formation on the contact force-intrusion curves, the deflection and the energy absorption rate of the bumper back-beam was examined. From the results of the examination, a proper design of the bumper back-beam was acquired. The bumper back-beam consisting of TPO was fabricated from the injection moulding process and the vibration welding. Pendulum crash tests were carried out using the fabricated bumper back-beam. The results of the tests showed that the designed bumper back-beam can satisfy requirements of the federal motor vehicle safety standard (FMVSS). Through the comparison of the previously designed bumper back-beam with the newly designed bumper back beam, it was noted that the weight of the designed bumper back-beam is lighter than that of the previously designed bumper back beam by nearly 16 %. In addition, it was considered that the newly designed bumper back beam can improve recycling of the bumper back-beam.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.181-188
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• 2013

The effect of transition metal ion exchange into UZM-9 zeolite with LTA framework on its deactivation in methanol-to-olefin (MTO) conversion was discussed. The ion exchange of copper, cobalt, nickel, and iron did not induce any notable change in the crystallinity, crystal morphology, and acidity of UZM-9. The small cage entrance of UZM-9 caused the high selectivity to lower olefins in the MTO conversion, while its large cages allowed the rapid further cyclecondensation of active intermediates, polymethylbenzenes including hexamethylbenzene, resulting in a rapid deactivation. The UZM-9 containing copper and cobalt ions showed considerably slow deactivations. The interaction between transition metal ions and polymethylbenzene cation radicals, the active intermediates, generated in the MTO conversion stabilized the radicals and slowed down the deactivation of UZM-9.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.184-192
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• 2012

For use as recyclable power cable insulations without dielectric oil, technology trends of IPP based thermoplastic polyolefin elastomer(TPO) nanocomposites were reviewed. In 2010 research results of IPP nanocomposite dielectrics for power capacitors showed promising high voltage properties except dielectric loss. Research of IPP based TPO nanocomposites for automotive exterior parts revealed considerable improvements of mechanical properties including impact strength, especially minimization of compatibilizer content, the origin of dielectric loss. A study on electrical properties of IPP based TPO nanocomposites containing a few weight percent of nanofillers for power cable insulations is suggested.

• Polymer(Korea)
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• v.38 no.4
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• pp.496-501
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• 2014

Polyalphaolefin (PAO) is a synthetic lubricant that is superior to mineral-based lubricants in terms of physical and chemical characteristics such as low pour point (PP), and high viscosity index (VI). This paper first reports a novel preparation route for a synthetic lubricant via alkylation of isoparaffins using a peroxide initiator without olefin. Alkylation of three kinds of isoparaffins such as i-$C_{16}$, i-$C_{18}$, and i-$C_{23}$ as well as alkylation of i-$C_{18}$ with 2-pentene using di-tert butyl peroxide initiator were conducted under various conditions to confirm alkylation reaction from isoparaffins themselves i.e; Single-molecule alkylation. Various properties of each alkylates (VI and PP) were investigated as a synthetic lubricant. Single-molecule alkylation made from i-$C_{16}$ a,nd i-$C_{18}$ showed ultra high VI (>140) and low PP (< $-30^{\circ}C$).

• Membrane Journal
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• v.26 no.1
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• pp.32-37
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• 2016

The poly(vinyl alcohol) $(PVA)/AgCF_3SO_3/Al(NO_3)_3$ electrolyte membrane was fabricated to prepare for highly permeable facilitated olefin transport membrane, compared with poly(vinylpyrrolidone) $(PVP)/AgCF_3SO_3/Al(NO_3)_3$ complex. In order to examine the characteristics of $PVA/AgCF_3SO_3/Al(NO_3)_3$ membrane, we used the analytical methods such as SEM, FT-IR, and FT-Raman. The best separation performance was observed at the mole ratio of 1 : 1 : 0.01 $PVA/AgCF_3SO_3/Al(NO_3)_3$ among various $Al(NO_3)_3$ concentration. As a result, the selectivity was 12 and mixed-gas permeability was 3.5 Barrer. Furthermore, the selectivity and permeability remained constant for up to 115 h.

• Membrane Journal
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• v.27 no.4
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• pp.313-318
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• 2017

For the separation of olefins/paraffins, $Poly(ethylene oxide)(PEO)/AgBF_4/Al(NO_3)_3/Ag_2O$ composite membranes were prepared. When $Ag_2O$ was introduced, the initial selectivity and permeance of composite membranes were observed to be 13.7 and 21.7 GPU, respectively. The increase in performance compared to the initial performance of $PEO/AgBF_4/Al(NO_3)_3$ membrane (selectivity 13 and permeance 7.5 GPU) was thought to be due to the increase of Ag ion activity due to the addition of $Ag_2O$. However, performance degradation over time was observed, which was thought to be due to the polymer matrix PEO. Since the PEO polymer could not stabilize the $Ag_2O$ particles, the $Ag_2O$ particles becmae aggregated together as the solvent evaporates, and $Ag_2O$ acts as a barrier. As a result, the permeance decreases over time.

• Polymer(Korea)
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• v.37 no.2
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• pp.156-161
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• 2013

Phenolic antioxidants are effective stabilizers that provide excellent long-term heat stability by preventing thermo-oxidative degradation during processing and service life. However, under a selected set of circumstances, certain types of phenolics have been susceptible to discoloration due to prolonged storage in an environment containing oxides of nitrogen. It is investigated that the effect of addition of secondary antioxidant and chemical structure of primary antioxidant on discoloration of amorphous poly-${\alpha}$-olefin (APAO), which is especially prone to be decomposed in high processing temperature. From the result, it is concluded that a higher level of steric hindrance of phenolic antioxidant provided by long alkyl chain allows a more enhanced synergic effect with secondary antioxidant.