• Elastomers and Composites
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• v.48 no.2
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• pp.114-124
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• 2013

To study the effects of structural difference and fatty acid chain length of glyceride, new dispersion agents having various glyceride structures such as mono-, di-, and tri-, were prepared using glycerol extracted from palm oil and fatty acid having various chain length ranges from 12 to 18. These dispersion agents were mixed with the rubber compounds and compared with conventional metal salt dispersion agents. Glyceride dispersion agent provided remarkable improvement in silica dispersion, compared to metal salt fatty acidic one, even though the viscosity of mixtures was relatively high due to low lubricating effect, and this was approved by mechanical properties, wear properties, and Payne effect. Also, the longer in chain length of fatty acid and the smaller in numbers of fatty acid, the dispersity of silica was improved.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.173-185
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• 2018

Effects of three different types of dispersions and flow improving additives composed with fatty acid esters, fatty acid metal salts and amide compound on the vulcanization and the mechanical properties properties of rubber compounds of EPDM and carbon black as fillers. were investigated using Mooney viscometer, moving die rheometer, hardness tester, and universal test machine. The aging characteristics of vulcanized EPDM compounds were also investigated. The Mooney viscosity measured at $125^{\circ}C$ showed a tendency to decrease in the order of amide type> metal salt type > ester type additive. Scorch time showed little or no difference with the addition of ester or metal salt type additives, but the amide type additive shortened a scorch time more than one minute. Rheological measurement data obtained at $160^{\circ}C$ showed that the vulcanization time was faster for metal salt type and amide type additive systems. Delta torque values of EPDM compound increased with metal salt type and amide type additives, but slightly decreased with ester type additive. The tensile strength of the EPDM compound was greatly improved when an ester type additive was added, but the amide type or metal salt type additive had no significant effect. The elongation was significantly improved for metal salt type additive, while the rest were not significantly affected. The tear strength of the EPDM compounds increased with the addition of all kinds of additives, and it increased remarkably in the case of metal salt type additive. Hardness of the EPDM compounds was nearly same value regardless of additive types. The thermal aging of the EPDM blend at $100^{\circ}C$ for 24 h showed little change in the case of metal salt type or amide type additive, but the elongation tends to decrease by 10-20% for all EPDM compounds containing additives.

• Elastomers and Composites
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• v.45 no.2
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• pp.100-105
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• 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
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• v.37 no.3
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• pp.170-176
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• 2002

Effects of type and loading level of process aids on the rheological and mechanical properties of styrene-butadiene rubber (SBR) compound were investigated. Five commercial grades of process aids composed of fatty acids and their various derivatives such as metal salts, esters, alcohols and amides were selected. The reduction in Mooney and shear viscosities was higher for metal salt-type process aids but lower for the process aids containing high molecular weight fatty acid alcohols and esters with increasing the loading of process aids. Tensile modulus generally decreased, while heat-build-up increased with increased process aids content. No considerable effect was observed for ulimate properties such as tensile strength and elongation at break.

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

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.23 no.3
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• pp.133-141
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• 2017

This article described the development of transparent antimicrobial oxo-biodegradable (AOB) film with the function of enhanced freshness of food by employing oxo-biodegradable masterbatch (MB) and antimicrobial MB together with organic metal salt, organic acid, or unsaturated fatty acid. Antibacterial test of the AOB film with the different contents of the antimicrobial MB resulted in the significant freshness extension of plum. Tensile strength and elongation rate of the AOB films before UV treatment were similar to those of polyethylene films used as control. The reduced mechanical properties of AOB film after UV treatment (340 nm) suggested that the AOB film could be degraded by oxo biodegradation. The developed AOB films can effectively prevent decomposition of food by providing antibacterial function and preserving freshness.