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Spherical silica particles were treated with a mixture of silane coupling agents with mercapto functional groups and dialkoxy or trialkoxy groups. The surface coverage, which indicates the number of layers covering the silica surface, was in the range from 1.6 to 6.0. The molecular mobility of the treated layer was analyzed with 1H‐NMR spectroscopy. The silane chain became more flexible with increasing dialkoxy structures in the mixture and with increasing surface coverage. The stress–strain behavior was measured for a composite consisting of the treated silica and vulcanized polyisoprene rubber (PIR). There was no influence of the dialkoxy and trialkoxy mixing ratio for near monolayer coverage. In the case of the pure dialkoxy and low trialkoxy contents, a higher stress was observed at the same strain for surface coverages of 2.4–3.8. However, a longer length flexible silane chain, that is, with a surface coverage of 6.0, was disadvantageous for the reinforcement effect. The results of pulse NMR analysis of the unextracted PIR on the particle surface and swelling test indicate that the reinforcement effect was strongly affected both by entanglement and the crosslinking reaction between the silane chain and PIR at the interfacial region. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

ABSTRACT:To improve the dispersibility of carbon microcoil (CMC) in solvents and polymer matrices, the grafting of copolymer containing vinyl ferrocene (VFE) onto surface by ligand-exchange reaction with ferrocene moieties of the copolymer and polycondensed aromatic rings of CMC was investigated. The copolymer containing VFE was prepared by the radical copolymerization of VFE with vinyl monomers, such as methyl methacrylate (MMA) and styrene (St), using 2,2 0 -azobisisobutyronitrole as an initiator. It was found that by heating of CMC with poly(VFE-co-MMA) and poly(VTE-co-St) in the presence of AlCl 3 and Al powder as catalyst, these copolymers were grafted onto the surface: the percentage of grafting reached to 64.2%. On the contrary, in the absence of AlCl 3 , no grafting of the copolymer was observed. The grafting of polymers onto the CMC surface was confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR), thermal decomposition gas chromatography-mass spectroscopy (GC-MS) and fieldemission scanning electron microscope (FE-SEM). Therefore, it is considered that the copolymer was grafted onto CMC surface by ligand-exchange reaction with ferrocene moieties of the copolymer and polycondensed aromatic rings of CMC. The polymer-grafted CMC gave a stable dispersion in solvents for grafted polymer.

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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