• Journal of the Korean Applied Science and Technology
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• v.26 no.3
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.62-69
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• 1998

Mechanical properties of polyethyleneglycol(PEG)/cyclo-tetramethylene tetranitramine(HMX) propellant were studied by adding polycaprolactone(PCP) and silane derivatives as coupling agent. Mechanical properties of the propellant were enhanced by increasing the content of PCP which was partially replaced with PEG. PCP/HMX propellant showed 17% increase in maximum tensile strength and 59% increase in elongation compared to those of PEG/HMX propellant. However, as the content of PCP was increased, the hydrolytic stability of this propellant was found to be deteriorated due to the ester group of PCP by measuring hardness drop of cured propellant and swell ratio difference of PEG/PCP binder stored at $40^{\cire}C$ and 90% relative humidity. Hardness of the PEG/PCP/HMX propellant was decreased with increasing triethoxysilyl propionitrile(TESPN) and dinitrosalicylic acid (DNSA) content from accelerated aging at $60^{\cire}C$.

• Membrane Journal
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• v.17 no.1
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• pp.44-53
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• 2007

The primary objective of this study is to increase the extent of water flux and fouling resistance of nano-filtration or reverse osmosis membranes. This study was performed to investigate the effect of surface characteristics of silane coated membranes on modified fouling index. Commercial polyamide composite RO membrane (RE1812-LP) and NF membrane (ESNA4040-LF) were treated with silane coupling agents in ethanol at five different concentrations. The silane coupling reagent, aminopropylmethoxydiethoxysilane, contains one aminoalkyl and three alkoxy groups. The hydrophilic effect of aminoalkyl group of APMDES on the permeability and fouling resistance of the modified membrane was examined. The surfaces of the modified membranes were characterized by FE-SEM, contact angle analyzer, and zeta potentiometer in order to confirm successful sol-gel methods. The modified NF membranes showed significantly enhanced water flux and fouling resistance without a decrease in salt rejection in divalent ionic feed solution.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1037-1044
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• 1997

Mechanical properties and water stability of HAC/PVA based MDF cement composite were investigated using polyurethane(PU) resin, silane coupling agent and various PVA. The results were as follows ; The flexural strength of MDF cement composite increased as increasing with PVA content. Low-viscosity PVA developed higher flexural strength than high-viscosity PVA under a drying curing condition. But the strength of water immersed specimen decreased. Water stability of MDF cement improved as increasing with content of PU. Consequently, water stability of polyurethane 7% added MDF cement was about 2 times higher than that of the controlled specimen. Furthermore, the strength and water stability of diamine group based silane couling agent in using MDF cement increased and improved dramatically.

• Membrane Journal
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• v.16 no.2
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• pp.106-114
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• 2006

This study is concerned with preparation of chlorine resistant (CR) thin layer composite (TFC) membranes. The novel method for making CR membranes from commercially available RO membranes is based on sol-gel condensation of trialkoxyalkylsilane derivatives. The silane coupling agents used in this study have different number of alkyl carbon chain group (methyltriethoxysilane; METES and octyltriethoxysilane; OCTES). The OCTES composite membranes have a significant tolerance to chlorine compared to commercial polyamide RO membrane or METES composite membranes. The surface properties of membranes were examined to explain a significant difference of chlorine tolerance between OCTES composite membrane and the other two membranes. In this study, we tried several surface analyses to explain difference of chlorine tolerance. The element composition results of surface analysis by EDX confirmed that both silane fixed on polyamide firmly, The surface roughness and contact angle results showed long chain alkyl group of OCTES enhancing hydrophobicity considerably than METES. The hydrophobicity plays an important role in chlorine resistance of membrane.

• Elastomers and Composites
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• v.42 no.2
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• pp.102-106
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• 2007

Water swelling behaviors of SBR vulcanizates with different reinforcing systems of carbon black, silica without a coupling agent, and silica containing a coupling agent were studied. Distilled water and 3.5% NaCl solution were used as swelling media. The water swelling ratios in the distilled water were higher than those in the salt solution. The water swelling ratios of the carbon black-filled samples were lower than those of the silica-filled ones. For the silica-filled SBR vulcanizates, the specimens without the silane coupling agent had higher water swelling ratios than those containing it. Water swelling behaviors of SBR composites with different 1,2-unit contents were also compared. The water swelling ratios tended to decrease by increasing the 1,2-unit content.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.581-583
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• 1993

One of the principal problems encountered in the use of fiber reinforced composites is to establish an active fiber surface to achieve maximum adhesion between resin and fiber surface. In order to improve the interface bonding, the surface of glass fiber should be treated with silane coupling agent in ordinary composite manufacturing processes. However, the price of the coupling agent is very high and in the treating process voids are formed, which decreasees electrical and mechanical strength. We want to develope new process that will overcome the disadvantage of the coupling agent and achieve maximum adhesion at the interface between resin and fiber by active plasma treatment on the glass fiber surface. In this study, we investigate the improvement of contact angle on the glass plate surface as the first step in developing new GFRP.

• Polymer(Korea)
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• v.27 no.4
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• pp.299-306
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• 2003

It is well known that the interaction and adhesion between the glass fiber (GF) and polymer matrix has a significant effect in determining the properties of fiber-reinforced materials. Therefore, it is one of important considerations to modify the surface of glass fiber with an appropriate sizing. We investigated the treatment method of glass fiber with coupling agent to improve the interaction of the interfacial region. The correlation between interfacial property and interphase microstructure was also examined in an attempt to realize a proper morphology at the glass fiber surfaces.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.216-219
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• 1987

Dielectric and Mechanical Properties of Mica flake/ Epoxy Composite are investigated. The Mica content is about 50 wt % and its thickness is about $240{\mu}m$. The finished Mica flake/Epoxy Composite contains about 0.1-1.0 wt % of aminosilane coupling agent. Ruby Mica filler and high temperature curing Epoxy resin are used. From the viewpoint of dielectric and mechanical properities. the optimum properties is obtained for the sample post cured at $130^{\circ}C$ for 5 h ours after curing at $80^{\circ}C$ for 2 hours and with 0.5 weight % silane coupling agent.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.791-796
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• 2013

In this study, the mechanical properties of a carbon fiber/polypropylene composite were evaluated according to the carbon fiber surface treatment. Carbon fiber surface treatments such as silane coupling agents and plasma treatment were performed to enhance the interfacial strength between carbon fibers and polypropylene. The treated carbon fiber surface was characterized by XPS, SEM, and single-filament tensile test. The interlaminar shear strength (ILSS) of the composite with respect to the surface treatment was determined by a short beam shear test. The test results showed that the ILSS of the plasma-treated specimen increased with the treatment time. The ILSS of the specimen treated with a silane coupling agent after plasma treatment increased by 48.7% compared to that of the untreated specimen.