Topographical observation of silane-treated inorganic surface using atomic force microscopy

Fujii

Nakamura

et al. 2013

Composite Interfaces

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The influences of alkoxy group number and loading method of silane coupling agents on the mechanical properties of a styrene-butadiene rubber/silica composite were investigated. Mercapto functional silane coupling agents with dialkoxy and trialkoxy structures were used. The pre-treatment method and the integral blend method were compared. Both the fracture stress and modulus at 200% strain were higher in the pre-treatment than in the integral blend for dialkoxy type composites. However, they were higher in the integral blend than in the pre-treatment for trialkoxy-type composites. The interaction between the silane chains on the silica surface and the rubber molecular chains at the interfacial region was estimated by 1 H pulse nuclear magnetic resonance spectroscopy using an unvulcanized silica/ rubber mixture. It was found that the binding of rubber molecular chains by the silane chains was higher in the pre-treatment system for dialkoxy-type composites, whereas it was higher in the integral blend for trialkoxy-type composites. The reason is proposed as follows: in the pre-treatment for dialkoxy type, a linear silane chain formed in the case of multi-layer coverage. The silane chain entangled with the rubber chain in the interfacial region and improved the reinforcement effect. For the trialkoxy type, a network structure formed using the pre-treatment method, lowering the amount of entanglement. However, in the integral blend for trialkoxy type, the formation of the silane network and the entanglement progressed simultaneously during the preparation process. A well-entangled interfacial region was formed.

Section: Introductionmentioning

confidence: 99%

Tensile properties of styrene-butadiene rubber/silica composites with mercapto functional silane coupling agents: influences of loading method and alkoxy group number

Fujii

Nakamura

et al. 2013

Composite Interfaces

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“…We have investigated the effect of interfacial adhesion between inorganic fillers surface-treated with various silane coupling agents and a matrix polymer on the mechanical properties of these composites [1][2][3][4][5][6][7][8]. Surface treatment of spherical silica particles using a silane coupling agent with a mercapto group was previously [7] conducted and the structure of the silanelayer formed on the silica surface was analyzed by 1 H pulse nuclear magnetic resonance (NMR).…”

Section: Introductionmentioning

confidence: 99%

Influences of the alkoxy group number and treatment condition on the structure of glycidoxy functional silane-treated layer on silica particles analyzed by¹H pulse NMR

Journal of Adhesion Science and Technology

Yamazaki

Fujii

et al. 2013

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The surface treatment of spherical silica particles using a silane coupling agent with a glycidoxy group was conducted and the effect of the alkoxy group number on the molecular mobility of the silane chain was investigated by 1 H pulse nuclear magnetic resonance (NMR). Silanes with di-alkoxy and tri-alkoxy structures were used, and the silica particles were treated with 2-propanol solution and heated at 120°C for 24 h after solvent evaporation. The surface coverage of the silica surface was in the range from two to three layers. For multilayer coverage, linear chain and network structures were expected to form on the surface by polycondensation reaction using the di-and tri-alkoxy structures, respectively. However, the relaxation times for silane chains with both di-and tri-alkoxy structures measured by pulse NMR were short, which indicates that both silane chains formed rigid network structures. Fourier transform infrared spectroscopic analysis revealed that ring opening of the epoxy group occurred, followed by reaction to form the network structure, even with the di-alkoxy structure. Ring opening of the epoxy group could be reduced by setting the heating temperature at 80°C. There was a significant difference in flexibility between the silane-layers with di-and tri-alkoxy structures after heating at 80°C, as reflected by the relaxation time.

“…The effect of interfacial adhesion between inorganic fillers surface-treated with silane coupling agent and matrix polymer on the mechanical properties of the composites has been investigated [1][2][3][4][5][6][7][8][9][10][11]. A previous study described the surface treatment of spherical silica particles with mercapto-functional silane using di-and trialkoxy structures [8].…”

Section: Introductionmentioning

confidence: 99%

¹H pulse NMR analysis of silane-treated layers on glass fiber surfaces

Nakamura

Nishida

et al. 2012

Composite Interfaces

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The surface treatment of a glass fiber using mercapto-functional silane coupling agent having a di-or trialkoxy group has been studied. The surface of silane-treated fiber is observed by scanning electron microscopy. The treated layer looks hard like glass for the trialkoxy silane-treated, whereas it looks soft for the dialkoxy silane-treated. Molecular mobility of the treated layer is analyzed by 1 H pulse nuclear magnetic resonance spectroscopy. The amount of silane loading increases with increased silane concentration in the treatment solution. The relaxation time for the surface layer is longer for the dialkoxy structure than for the trialkoxy structure. The silane chain is flexible in the dialkoxy structure, but is rigid for the trialkoxy structure, independent of the loading amount of silane. The relaxation behavior for the mixture of the di-and trialkoxy structures is between those of the pure dialkoxy and trialkoxy structures and depends on the mixing ratio. The network density of silane chains on the glass fiber can be controlled by varying the mixing ratio of the di-and trialkoxy compounds. IntroductionThe effect of interfacial adhesion between inorganic fillers surface-treated with silane coupling agent and matrix polymer on the mechanical properties of the composites has been investigated [1-11]. A previous study described the surface treatment of spherical silica particles with mercapto-functional silane using di-and trialkoxy structures [8]. With multilayer coverage, hairy (linear chain) and network structures are expected to form on the surface by polycondensation reaction using di-and trialkoxy silanes, respectively. The molecular mobility of silane chain with such structures was investigated by pulse 1 H nuclear magnetic resonance spectroscopy (pulse NMR) [12][13][14]. The spin-spin (T 2 ) relaxation time obtained by measuring the free induction decay (FID) was longer for the dialkoxy structure than for the trialkoxy structure. The silane chain was flexible for the dialkoxy structure, whereas it was rigid for the trialkoxy structure.The treated silica particles were mixed with polyisoprene rubber (PIR) matrix and vulcanized, and the effects of loading amount and number of alkoxy groups in silane on the stress-strain curve of the filled PIR were investigated [6]. The stress at the same strain