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In order to reinforce the composite consisting of isoprene rubber (IR) and calcium carbonate (CaCO3) particles, the surface treatment of CaCO3 particles with a mixture of amino- and mercapto-functi...

The interfacial layer structure of a model incompatible polymer blend system was analyzed using 1H pulse nuclear magnetic resonance (pulse NMR) spectroscopy. Non-crosslinked and crosslinked poly(n-butyl methacrylate) particles with a mean size of ca. 0.9 μm were prepared by seeded emulsion polymerization, and the degree of crosslinking was varied. The particles were powdered using a freeze-dry method and dispersed in poly(vinyl chloride) by melt blending. Dynamic mechanical analysis indicated that the non-crosslinked particles were completely compatible. In contrast, mutual diffusion of the polymer chains in the crosslinked particles was restricted within the particle/matrix interfacial layer. As a result, an incompatible phase structure in which the crosslinked particles were dispersed in the continuous phase was formed. Pulse NMR analysis indicated that the interfacial layer thickness was in the range of 17–98 nm. The thickness decreased with an increase in the degree of crosslinking in the part...

The influences of debonding rate and temperature on the peel behavior of polyacrylic block copolymer/tackifier system were investigated. Poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) triblock copolymer (MAM) with hard block contents of 23 (MAM-23) and 16 wt.% (MAM-16) and a 1/1 blend with a diblock copolymer (MA) consisting of the same components (MAM-23/MA, total hard block content of 15 wt.%) were used as the base polymer. A special rosin ester was used as a tackifier at various contents in the block copolymer/tackifier system. The peeling process at the probe/adhesive interface during probe tack testing was observed using a high-speed microscope at 23 °C with debonding rate of 10 mm/s. Three different peeling mechanisms were observed. Type A, where peeling progressed linearly from the edge to the center of the probe without cavitation (MAM-23). Type B, where peeling progressed linearly from the edge to the center of the probe with cavitation (MAM-16). Type C, wh...

The H2 concentration was measured in the ventilated air of actual high-level liquid waste tanks of the Tokai reprocessing plant. It was compared with the value calculated from the parameters that w...

The formation of sawtooth-shaped stringiness during 90° peeling was investigated using crosslinked poly(n-butyl acrylate–acrylic acid) and poly(2-ethylhexyl acrylate–acrylic acid) random copolymers with an acrylic acid content of 5 wt.% and different crosslinking degrees as pressure-sensitive adhesives (PSAs). The gel fraction was measured by toluene extraction of PSA, and it increased with crosslinker content for both systems. The observed stringiness was sawtooth-shaped, but there were three different types; both the typical sawtooth shape and the frame formed at the front tip with interfacial failure, and the sawtooth shape formed with cohesive failure. The change in the stringiness shape was affected strongly by the gel fraction of PSA. The peel rate under constant peel load was measured and revealed that the peel rate was lowest upon formation of the front frame type. A good relation was found between peel rate and peel strength, with a greater peel strength upon formation of the front frame type. Th...

The surface treatment of spherical silica particles with silane coupling agents having various organic functional groups was conducted and the effect of the alkoxy group number on the molecular fle...

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 1H 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 tria...

Tack properties and peeling behavior of crosslinked polyacrylic pressure-sensitive adhesives were investigated. The model adhesive was a crosslinked poly(n-butyl acrylate-acrylic acid) random copolymer with an acrylic acid content of 5 mol% with various crosslinking degrees. Tack was measured using a probe tack test with probe rates of 1 and 10 mm/s and various contact time. The tack increased with contact time. The degree of tack rising with contact time decreased with an increase in crosslinking degree for 10 mm/s, while the tendency was opposite for 1 mm/s. The temperature dependency of tack was measured with a contact time of 30 s. The tack peak shifted to higher temperatures with an increase in crosslinking degree and probe rate. Peeling behavior was observed using high-speed microscopy. The peeling behavior changed from A to C with the decrease of peeling rate and crosslinking degree. A: Cavitation and peeling progressed simultaneously at maximum stress at 10 mm/s independent on the crosslinking deg...

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 1H 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, f...

The influence of tackifier structure on the temperature dependence of tack for a polystyrene block copolymer/tackifier system was investigated. A blend of polystyrene-block-polyisoprene-block- poly...

In this study, the adhesion properties of polyurethane (PUR) pressure-sensitive adhesive (PSA) were investigated. The PUR-PSA was prepared by the cross-linking reaction of a urethane polymer consisting of toluene-2,4-diisocyanate and poly(propylene glycol) components using polyisocyanate as a cross-linking agent. The peel strength increased with the cross-linking agent content and exhibited cohesive failure until the maximum value, after which it decreased with interfacial failure. The PUR-PSA exhibited frequency dependence of the storage modulus obtained from dynamic viscoelastic measurements, but did not show dependence of the tack on the rolling rate measured using a rolling cylinder tack test under the experimental conditions used, which is quite different from the acrylic block copolymer/tackifier system. The PUR-PSA showed strong contact time dependence of tack measured by a probe tack test. The tendency was significantly larger than for the acrylic block copolymer/tackifier system. Therefore, the s...

Hydroxyapatite (HAp) nanoparticle-coated poly(ϵ-caprolactone) (PCL) microspheres were fabricated via surfactant-free ‘Pickering-type’ emulsion solvent evaporation method in the absence of any molec...

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 1H 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 o...

The adhesion strength of an adhesive is affected by two factors: the development of interfacial adhesion and the cohesive strength of the adhesive. In order to evaluate the relative contributions of these two factors, the tack of polyacrylic block copolymer-based adhesives was measured using a probe tack test. For this purpose, three model adhesives were prepared: poly(methyl methacrylate)-block-poly(n-butyl acrylate)-block-poly(methyl methacrylate) triblock copolymer (A), a mixture of the triblock and poly(methyl ethacrylate)-block-poly(n-butyl acrylate) diblock copolymer (7/3, w/w) (B), and a mixtureof the triblock and poly(n-butyl acrylate) oligomer (8/2, w/w) (C). The tack measured at room temperature was in the order B ≈ C > A and increased gradually with an increase in the contact time. The temperature dependence of tack showed peak tack values above room temperature, and the peak tack temperature was in the order A > B > C. The storage and loss moduli measured by dynamic mechanical analysis were al...

The surface treatment of spherical silica particles with silane coupling agent having mercapto group was carried out and structure and amount of silane nanolayer formed on silica surface were analyzed using 1H pulse nuclear magnetic resonance (NMR) and thermogravimetric analysis, respectively. Effects of loading amount and number of alkoxy groups of silane on the structure were investigated. Silanes with dialkoxy and trialkoxy structures were used as silane coupling agents and the loading amount of the silane on the silica surface was varied from one to nine times the amount required for monolayer coverage. The relaxation time was longer in the dialkoxy type than in the trialkoxy type of silane. The relaxation time increased with increase of the loading amount of silane for the dialkoxy type; on the other hand, there was no influence of the loading amount of silane for the trialkoxy type. It was found that the silane structure was flexible for the dialkoxy type, whereas it was rigid for the trialkoxy type...

Effects of polystyrene block content on adhesion property and phase structure of polystyrene block copolymers were investigated. Polystyrene-block-polyisoprene-block-polystyrene triblock and polystyrene-block-polyisoprene diblock copolymers with different polystyrene block contents in the range from 13 to 35 wt% were used. In the case of the low polystyrene block content (below 16 wt%), a sea-island structure was observed: near-spherical polystyrene domains having a mean diameter of about 20 nm were dispersed in polyisoprene matrix. The phase structure changed from a sea-island structure to a cylindrical structure with an increase of polystyrene block content (over 18 wt%). Peel strength decreased with an increase of polystyrene block content and the pure triblock copolymers had lower peel strength than their blends with the diblock copolymers. Pulse nuclear magnetic resonance studies indicated that molecular mobility of polyisoprene phase decreased with an increase of polystyrene block content, and the m...

Influence of filler size on impact properties for polypropylene (PP)/elastomer/filler ternary composites was investigated. Calcium carbonate (CaCO3) particles with a diameter in the range from 120 to 1200 nm were used as a filler and polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) was used as an elastomer. In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. In the case that SEBS elastomer volume fraction was below 0.12, the impact strength improved gradually with a decrease of CaCO3 mean diameter from 1200 to 160 nm. In the case that SEBS volume fraction was above 0.17, the impact strength improved significantly by the incorporation of CaCO3 particles with a mean diameter in the range from 120 to 900 nm. However, the impact strength hardly improved by the incorporation of CaCO3 particles with a mean diameter of 1200 nm.

The topography of mica surface after treatment with silane coupling agent having a mercapto group was studied using an atomic force microscope. The cleaved mica plate was used as a model inorganic surface. The effect of treatment condition on the topography of the mica surface was investigated. Agglomerates consisting of self-condensed silane molecules were observed on the surface. However, their amount and size were smaller than those for silanes having other organo-functional groups such as amino, methacryloxy and vinyl groups. Aqueous and water/2-propanol mixture solutions gave a smoother surface as compared with a 2-propanol solution. There was no significant influence discernable from di- and trialkoxy structures. The aqueous solution of silane coupling agent having a mercapto group showed an acidic pH. This was the reason why the smoother silane-treated layer was formed by the silane with the mercapto group than by those with other organic functional groups, because the silanol group generated by hy...

Polypropylene (PP)/elastomer/fine filler particle ternary composite was prepared using polystyrene-block-poly(ethylene-butene)-block-polystyrene triblock copolymer (SEBS) or carboxylated SEBS (C-SEBS) as elastomer and calcium carbonate (CaCO3) having mean size about 160 nm as filler. First, SEBS (or C-SEBS) and CaCO3 particles were mixed to form master batch. Second, the prepared master batch and PP matrix were kneaded. In the PP/SEBS/CaCO3 ternary composite, CaCO3 particles and SEBS particles were dispersed in the PP matrix separately. In the PP/C-SEBS/CaCO3 ternary composite, CaCO3 particles were encapsulated in C-SEBS and formed a core–shell structure at lower CaCO3 concentration; however, some CaCO3 particles were dispersed in PP matrix at higher CaCO3 concentration. In the PP/SEBS/CaCO3 composite, the impact strength increased with the amount of incorporated CaCO3 particles. Whereas, in the PP/C-SEBS/CaCO3 composite, the impact strength increased with the amount of CaCO3 particles dispersed in PP mat...

The effect of compatibility of polymer and tackifier on the adhesion properties of pressure-sensitive adhesive tape was investigated. For this purpose, a model pressure-sensitive adhesive tape was ...

The surface treatment of glass beads, chosen as model filler, with silane coupling agent with multilayer coverage was carried out. The treated beads were incorporated with poly(vinyl chloride), chosen as a typical ductile polymer. The effects of the organic functional group of silane and silane chain length on the mechanical properties of the filled composite were investigated. For this purpose, silanes having aminopropyl or methacryloxypropyl group as organic functional group with dialkoxy structure were used. The silane chain length on the bead surface varied from one to nine times the amount required for monolayer coverage. The yield stress was higher in the order of aminopropyl silane-treated > methacryloxypropyl silane-treated > untreated beads-filled systems. However, the elongation at break had a quite opposite order. The effect of silane chain length appeared only in the methacryloxypropyl silane-treated system. The yield stress increased slightly, whereas the elongation at break decreased with th...

The topography of silane layers deposited on an inorganic surface was observed using atomic force microscopy. For this purpose, cleaved mica plates were treated with some silane coupling agents at various conditions. Silanes having a vinyl group as the organic functional group with mono-, di- and trialkoxy structures were used. Four different solvents for silane solutions, 2-propanol, 2-propanol/water mixture, water and toluene, were used. The pH of the aqueous solution was controlled. As a result, the suitable solvent and pH were identified in order to obtain a smooth silane layer. The solubility of silane in the solution, the wettability of silane onto the inorganic surface and the depression of the self-condensation of silane molecules in the solution were found to be important parameters for this purpose.

The effect of tackifier on the adhesive properties of a model pressure-sensitive adhesive tape was investigated. For this purpose, a model system consisting of poly(styrene-isoprene-styrene) triblock copolymer as the base polymer and a typical aliphatic petroleum resin as the tackifier was prepared. The tackifier content ranged from 10 to 60 wt%. The tackifier used has a good compatibility with polyisoprene, whereas it has a poor compatibility with polystyrene. The 180° peel adhesion was measured. The peel adhesion increased with the tackifier content, while the degree of increase became more significant above 40 wt%. The pressure sensitivity appeared obviously and the maximum peel adhesion was obtained without heating above 40 wt%. The phase structure was determined using pulse 1H-NMR, transmission electron microscopy and dynamic mechanical analysis. A phase structure in which spherical polystyrene domains with a mean size of about 20 nm were dispersed in the polyisoprene continuous phase was observed. I...

The topography of the silane-treated layer on an inorganic surface was observed using an atomic force microscope. For this purpose, the cleaved mica plate was treated with some silane coupling agent at varying conditions. The silanes having aminopropyl or methacryloxypropyl group as organofunctional groups with di- or trialkoxyl structures were used. Three different solvents for silane solution — 2-propanol, 2-propanol/water mixture and water — were used. The pH of the aqueous solution was controlled. As a result, the most suitable solvent and pH in order to obtain smooth silane layer was clarified. The solubility of silane molecules in the solution, the wettability of silane molecule onto inorganic surface, and prevention of the mutual condensation of silane molecules in the solution were found to be important parameters for this purpose.

The reactivity of the alkoxy group in a silane coupling agent toward inorganic surfaces was investigated, and the structure of a silane-treated layer on the particle surface was analyzed. For this purpose, the various inorganic filler particles, SiO2, Al(OH)3, Mg(OH)2, Al2O3, and CaCO3 were treated with γ-mercaptopropyltrimethoxysilane. A strong interaction between the particle surface and the silane due to the hydrogen bonding and ionic interaction was confirmed except for CaCO3 by electron spectroscopy for chemical analysis (ESCA). The structure of the silane layer on the particle surface was affected significantly by both the amount of added silane and the treatment conditions. Different silane structures, such as monolayer- or network-like, were formed on the particle surface. Their influences on the mechanical properties of filled vulcanized rubber were also investigated. The silane-treated filler particles, except CaCO3, showed ability as a semi-reinforcing filler for vulcanized rubber. However, the...

The surface treatment of glass beads, chosen as a model filler, was carried out using four different silane coupling agents with multilayer coverage. For this purpose, silanes having an aminopropyl or a methacryloxypropyl group as an organofunctional group with di- or tri-alkoxy structures were used. The amount of silane detected on the bead surface was four to six times that required for a monolayer coverage. The topography of the silane layer on the bead surface was observed using an atomic force microscope. The topography was strongly affected by the composition of the silane solution and the number of alkoxy groups in the silane. The effects of the organofunctional group and the number of alkoxy groups of the silanes on the mechanical properties of bead-filled poly(vinyl chloride), chosen as a typical ductile polymer, were investigated. A higher yield stress was observed for the silane with an aminopropyl group than for that with a methacryloxypropyl group. Furthermore, for each organofunctional group...

The effects of interfacial structure and particle size on the mechanical properties of an particulate-filled composite have been investigated using a model system. For this purpose, uncrosslinked and crosslinked poly(methyl methacrylate) particles having the mean size of about 0.8 μm are prepared by a seeded emulsion polymerization, and then the amount and the distribution of crosslink points in the particles are varied. The obtained emulsion particles are powdered by a freeze dry method and dispersed into poly(vinyl chloride) matrix by a melt blending. The uncrosslinked particles are completely dissolved in the matrix due to a good compatibility of poly(methyl methacrylate) with poly(vinyl chloride). In the case of the crosslinked particles, the mutual diffusion of the polymer molecules is restricted within the particle/matrix interfacial regions by the crosslink points. The interfacial structures with different concentration slope dependent upon the amount and the distribution of inner crosslink points ...

The novel urethane-type crown ethers were obtained by the thermolysis of aminimides containing ω-hydroxy-oligo(oxy-ethylene) group in acyl moiety.