• Polymer(Korea)
• /
• v.31 no.1
• /
• pp.80-85
• /
• 2007

Maleic anhydride (MA) modified ethylene-propylene-diene terpolymer (MEPDM) was pre-pared from solution polymerization. MEPDM-g-PST copolymer was prepared by melt polymerization of male ate d EPDM and quaternary ammonium silyl polydimethylsiloxane -7,7,8,8- tetracyanoquinodimethane (TCNQ) adduct (PST) in internal mixer and MEPDM-g-PST/HDPE/CB (MPEC) was prepared by com-pounding HDPE, MEPDM-g-PST copolymer and carbon black (CB, 5, 10, 15, and 20 phr), and HDPE/ CB (PEC) by compounding HDPE and CB (5, 10, 15, and 20 phr), respectively. The structure of MEPDM-g-PST copolymer was confirmed by measuring the FTIR. The maximum grafting ratio of MA onto EPDM was 2.35%. The thermal and mechanical properties of the composites were measured and dispersion characteristics of CB in matrix show that CB in MPEC was better dispersed than that in PEC composite.

• Polymer(Korea)
• /
• v.35 no.3
• /
• pp.228-231
• /
• 2011

The rate of vulcanization of nonpolar ethylene-propylene-diene terpolymer(EPDM)/carbon black compounds was investigated by using hot air and microwave as a heating source. The present study parameters such as heating source, sample thickness, and loading of an additive. The compound thickness was the main factor in the hot air vulcanization. It was due to the poor thermal conductivity of EPDM; that is, the thicker thickness, the lower vulcanization rate. For 100% vulcanization, the compound with 3 mm thickness required 7 min at $250^{\circ}C$ in the hot air system. However, the vulcanization of EPDM compounds by microwave system was not affected by the thickness while strongly dependent on the amount of a polar additive, carbon black. A compound with 80 phr of carbon black was perfectly vulcanized within 30 sec. These results suggest that the use of microwave as a heating source is an effective method for the vulcanization of compounds including a polar component.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.11a
• /
• pp.257-260
• /
• 2010

The purpose of this paper is to introduce a method to predict the case thermal insulation charred and erosion thickness as a function of the exposure time to combustion gases and in solid rocket motors. The sizing of the insulator requires a good estimation of the thermal and mechanical loads at the wall. The method is particularly suitable for internal insulation areas subjected to high radiative, convective heat fluxes and $Al_2O_3$ slag pool. The mathematical approach and lab-scale experiment were intentionally simplified in order to obtain some simple and rapid relationships particularly useful for trade-off studies and thermal insulation preliminary design. The method was utilized to compute the charred and erosion thicknesses of the insulation on the aft chamber domes. A comparison between theoretical and experimental insulator char thicknesses of the motor insulation is reported, indicating the applicability of the predictive method employed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.4
• /
• pp.321-328
• /
• 2009

Shock absorption performances of various rubbers were investigated by using drop impact test. Several types of rubber such as NR, NBR, EPDM, SR and PUR with three respective levels of shore hardness were used for the test. As in the cases, the absorbed impact energies in rubbers were measured under seven different loads against impact energy between 5-80J. The impact absorption efficiencies of the rubbers then were evaluated by means of both single impact energy condition and summation of all impact energy applied condition. As shown in the results, PUR and EPDM have better shock absorption performances than other rubbers. Further analysis was extended to determine a shear modulus of SR through the finite element implementation with Blatz-Ko model. As can be seen, relatively higher level of absorption energy results in a decreasing shear modulus.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2013.06a
• /
• pp.120-121
• /
• 2013

Recently, our country is to be diversification a leisure activity and tourism form by income level rise and traffic circumstance improvement. But Basic facilities expropriated these leisure activities have built an insufficient condition. Also, Building a facility, Introduced tools and materials import the whole quantity. Therefore, In this paper, it builds a tension mooring unit to use EPDM and Kevlar R29 and it develops a domestic marine circumstance through reliability based on robust design. It contributes to marine leisure culture activation and industry development.

• Elastomers and Composites
• /
• v.24 no.4
• /
• pp.276-289
• /
• 1989

This study deals with both effects of inorganic fillers to vulcanized rubbers such as NR, CR, EPDM, NBR & SBR and inorganic characteristics of domestic fillers in comparision with hard clay produced in the USA. The results were as follows. 1. Main ingredient of domestic clay "Ha-dong clay" was Halloysite, "No-ha Island" was Pyrophyllite with $\alpha$-Quartz, and both of "Hard clay" & "Hwa-soon clay" were proved to be Kaolinite by XRD, DT-TGA and chemical analysis by XRF. 2. Tensile strength value of SBR compounded with these fillers, was Hard clay $146kg\;f/cm^2$, Kaolinite $123kg\;f/cm^2$, Pyrophyllite $82kg\;f/cm^2$, Halloysite $80kg\;f/cm^2$, precipitated $CaCO_3\;27kg\;f/cm^2$, and ground $CaCO_3$ was $21kg\;f/cm^2$. These results showed the increase of seven times according to filler species. 3. The physical properties of non-crystalline rubbers, such as SBR, NBR & EPDM, compared with NR & CR, have been considerably changed according to crystalline phase, particle size, shape and surface structure of fillers. Especially, tensile strength value in case of SBR & EPDM, was differentiated about 1.5 times by the particle size of fillers. 4. In SBR, physical properties of rubber compounded with Kaolinite which was surface treated with fatty acid and silane, almost approach to the value of hard clay. 5. Delayed cure time of Kaolinite and decrease of rubber properties by $CaCO_3$ can be improved by blending kaolinite & $CaCO_3$ in the ratio of 2:1.

• Elastomers and Composites
• /
• v.48 no.4
• /
• pp.288-293
• /
• 2013

Crosslink characteristics of maleic anhydride-grafted EPDM (MAH-g-EPDM)/zinc oxide composite were investigated by weight losses after dichloroacetic acid (DCA)/toluene cosolvent extraction at different temperatures and by measurement of crosslink densities. The chemical changes were analyzed using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The weight losses by extraction at high temperature ($90^{\circ}C$) were remarkably greater than those at room temperature and those by DCA/toluene cosolvent extraction were greater than those by toluene one by more than 5 times. The crosslink densities were measured after the solvent extraction, and the second crosslink densities were higher than the first ones. The first crosslink density was lower when the extraction temperature was high, and it was much lower for the toluene extraction than for the DCA/toluene cosolvent extraction. The second crosslink density of the sample extracted with DCA/toluene cosolvent was greater than that extracted with toluene. The extracted components were depending on the extraction solvents and temperatures, for example; only strong crosslinked networks were remained when extracting with DCA/toluene cosolvent at high temperature, while only uncrosslinked polymer chains were extracted when extracting with toluene at room temperature. Therefore, crosslink characteristics of the MAH-g-EPDM/zinc oxide composite can be analyzed by comparison of the extracted components according to the extraction solvents and temperatures and by measurement of successive crosslink densities.

• Elastomers and Composites
• /
• v.47 no.3
• /
• pp.210-215
• /
• 2012

Whitening phenomena of the EPDM composites with different inorganic filler compositions which were aged at $90^{\circ}C$ for 7 days in air and tap water atmospheres, respectively, were investigated. The aged samples in tap water containing stearic acid exhibited severe whitening phenomena, while all the samples aged in air did not show any whitening. Depending on the filler compositions, there was no big difference in the whitening phenomena. The whitening materials were analyzed using gas chromatography/mass spectrometry (GC/MS), image analysis, energy-dispersive X-ray spectroscopy (EDX), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The whitening materials were identified to be salts of stearic acid. The salts of stearic acid were formed by reaction of metal cation in tap water and stearic acid in the sample.

• Elastomers and Composites
• /
• v.45 no.2
• /
• pp.100-105
• /
• 2010

An EPDM article was aged in air, distilled water, tap water, NaCl/$CaCl_2$ solution, and $CaCl_2/FeCl_3$ solution for 7 days. The aging temperature was $90^{\circ}C$. The samples aged in air and distilled water did not appear the whitening, those aged in tap water, NaCl/$CaCl_2$ solution, and $CaCl_2/FeCl_3$ solution showed the whitening. Soluble organic materials were analyzed using GC/MS to identify the whitening materials, surface morphology of the aged sample surface was examined using image analyzer and SEM, and elemental analysis of the materials accumulated on the sample surface was performed using EDX. Principal reason to cause whitening might be formation of metal salt of fatty acid by reaction between metal cation and fatty acid.

• Elastomers and Composites
• /
• v.44 no.3
• /
• pp.315-322
• /
• 2009

Influence of blend mode of extender oil on the properties of thermoplastic vulcanizates (TPVs), based on an ethylene-propylene-diene copolymer (EPDM) and a polypropylene (PP), was studied. The EPDM/PP TPVs were prepared in an open roll mill using two different modes in blending sequence of paraffinic oil and phenolic curative, i.e., Oil-Cure and Cure-Oil modes. Degree of cross-linking by gel fraction and properties such as hardness, tensile strength, elongation at break, and melt flow rate were investigated as a function of extender oil content for the two modes. Little influence of the blend mode of extender oil on the degree of cross-linking and mechanical behaviors was observed. However, the use of Cure-Oil mode in the preparation of EPDM/PP TPVs resulted in a marked increase in the level of processability as reflected by melt flow index, as compared to the use of Oil-Cure mode.