Sumitomo Rubber Industries (Japan)

Abstract Evaluation for JENDL-3.3 has been performed by considering the accumulated feedback information and various benchmark tests of the previous library JENDL-3.2. The major problems of the JENDL-3.2 data were solved by the new library: overestimation of criticality values for thermal fission reactors was improved by the modifications of fission cross sections and fission neutron spectra for 235U; incorrect energy distributions of secondary neutrons from important heavy nuclides were replaced with statistical model calculations; the inconsistency between elemental and isotopic evaluations was removed for medium-heavy nuclides. Moreover, covariance data were provided for 20 nuclides. The reliability of JENDL-3.3 was investigated by the benchmark analyses on reactor and shielding performances. The results of the analyses indicate that JENDL-3.3 predicts various reactor and shielding characteristics better than JENDL- 3.2. KEYWORDS: JENDL-3.3nuclear dataevaluationreliabilityresonancecross sectionspectrumcovariancebenchmarkcriticalityshielding

Natural rubber (NR) is stored in latex as rubber particles (RPs), rubber molecules surrounded by a lipid monolayer. Rubber transferase (RTase), the enzyme responsible for NR biosynthesis, is believed to be a member of the cis-prenyltransferase (cPT) family. However, none of the recombinant cPTs have shown RTase activity independently. We show that HRT1, a cPT from Heveabrasiliensis, exhibits distinct RTase activity in vitro only when it is introduced on detergent-washed HeveaRPs (WRPs) by a cell-free translation-coupled system. Using this system, a heterologous cPT from Lactucasativa also exhibited RTase activity, indicating proper introduction of cPT on RP is the key to reconstitute active RTase. RP proteomics and interaction network analyses revealed the formation of the protein complex consisting of HRT1, rubber elongation factor (REF) and HRT1-REF BRIDGING PROTEIN. The RTase activity enhancement observed for the complex assembled on WRPs indicates the HRT1-containing complex functions as the NR biosynthetic machinery.

Abstract The effects of proteins and phospholipids in natural rubber (NR) on the strain-induced crystallization behavior during uniaxial deformation were studied by in-situ synchrotron wide-angle X-ray diffraction (WAXD) technique and simultaneous measurements of stress-strain relation. The influences of proteins and phospholipids in NR were evaluated separately by decomposition methods using deproteinization and lipase treatment, respectively. It was found that both components form a naturally occurring network, which is responsible for the strain-induced crystallizability of unvulcanized NR and the corresponding high mechanical property. This network also plays a significant role in strain-induced crystallization of vulcanized natural rubber.

Bulk glassy alloys have high tensile strength, while the Young’s modulus is lower by 20 to 40% than those for the corresponding crystalline alloys. These unique mechanical properties are effective to increase the coefficient of restitution at the impact between a golf club and a golf ball. Bulk glassy alloys have in general been produced by the copper mold casting and die casting methods. We have developed a new manufacturing process for Zr-based bulk glassy alloys. By the use of the new process, we have succeeded in producing a glassy Zr–Al–Ni–Cu alloy in a shell shape with a dimension of about 90×40 mm and a thickness of 3 mm for glassy driver golf clubs. It exhibits excellent mechanical properties such as tensile strength of 1700 MPa, Young’s modulus of 81 GPa, and impact fracture toughness of 130 kJ/m2. These properties are suitable for the material for driver golf club heads. The glassy driver golf club with the shell shape in the impact region was confirmed to have a high coefficient of restitution.

We report in situ nanostructures and dynamics of polybutadiene (PB) chains bound to carbon black (CB) fillers (the so-called "bound polymer layer (BPL)") in a good solvent. The BPL on the CB fillers was extracted by solvent leaching of a CB-filled PB compound and subsequently dispersed in deuterated toluene to label the BPL for small-angle neutron scattering and neutron spin echo techniques. The results demonstrate that the BPL is composed of two regions regardless of molecular weights of PB: the inner unswollen region of ≈ 0.5 nm thick and outer swollen region where the polymer chains display a parabolic profile with a diffuse tail. In addition, the results show that the dynamics of the swollen bound chains can be explained by the so-called "breathing mode" and is generalized with the thickness of the swollen BPL.

The dynamics of silica particles in unvulcanized rubber is investigated by X-ray photon correlation spectroscopy (XPCS). The results show the aging behavior of the dynamics; the dynamics of particles slows down as the aging time increases. This slowing down is not accompanied by a change in the configuration of aggregates in size scales of micrometers and sub-micrometers. The aging behavior depends on the type of silane coupling agent and the volume fraction of silica particles, while it does not originate from vulcanization. This study shows that complex microrheological phenomena occur even in industrial products. The relationship between these microrheological phenomena and macroscopic viscoelasticity is an open question.

Abstract The dynamically rolling tire is simulated by using an explicit finite element method. In this simulation, the complicated pattern shape and internal construction of the tire are modeled exactly since both these factors are very important for the performance properties of the tire. A very long calculation time is necessary for refined tire models, but, for practical tire development, the calculation time of this simulation is acceptable because of major advances in hardware, FEM software, and modeling techniques. The authors describe the model used in the simulation and report on the results of several properties under various rolling conditions of the tire evaluated by this method. The correlation between the simulation and the experiment appears good. Therefore, this simulation technique can be assumed very useful for actual tire development.

The addition of nanofillers to rubber matrices is a powerful route to improve the mechanical properties. Here, we focus on a molecular understanding of basic mechanisms that are important for the reinforcement in rubbers. The key role in this process is ascribed to bound rubber (BR) that engages with the matrix as well as with adjacent nanofillers. To date, this understanding has been impeded by the lack of experimental tools to directly probe the BR chains buried in a polymer matrix composed of the same polymer. To tackle this challenge, we combine neutron scattering/spectroscopy techniques with isotope-labeling and molecular dynamics simulations. The system is a simplified carbon-black-filled polybutadiene. The combined experimental and computational results provide new insights into the local structural and dynamical heterogeneities of BR chains and their interactions with the matrix polymer, highlighting (i) the structural partition of the bound chains into three components (i.e., trains, loops, and tails) and their fractions; (ii) their dynamical hierarchies, i.e., the trains that remain immobile on the filler surface, the loops that are fairly large and hence allow the interdigitation of matrix chains, and the tails with their unique characteristics to reach far out into the matrix and entangle with matrix chains. These multiple roles of the constituent components of the BR chains promote the formation of a well-developed adhesive polymer–filler interface, enhancing the elastic property of a filled rubber. The comprehensive understanding derived and validated by the model rubber will be translatable to many other polymer nanocomposites.

Abstract The chemical structures of natural rubber (NR) end groups are investigated by combining chemical treatments and sensitivity‐enhanced modern nuclear magnetic resonance (NMR) spectroscopy instruments equipped with a cryoprobe. The obtained 1 H NMR spectrum of the α‐end has improved signal intensity than that obtained with conventional instruments, as well as clearer splitting patterns due to the higher resolution given by the higher magnetic field. Through the 1 H/ 13 C 2D NMR experiments and the 1D NMR spectra of the model compounds, four types of α‐end structures are suggested. Two structures among them are considered related to those of mushroom‐derived NR found in the literature, whereas the others are not recognized to date. Solid‐state 31 P cross‐polarization/magic angle spinning (CP/MAS) NMR is also carried out to detect the phosphate group around the terminal.

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization ( P H ). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = −35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å −1 ) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å −1 ) decreased with increasing P H , which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H . At P H = −35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according to q −3.6 , which is consistent with the results for the SBR/CP mixture.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEffects of Shear Flow on Viscoelastic Properties of Polystyrene/Poly(vinyl methyl ether) Blends near the Phase Separation TemperatureYoshiaki Takahashi, Hirokazu Suzuki, Yoshiki Nakagawa, and Ichiro NodaCite this: Macromolecules 1994, 27, 22, 6476–6481Publication Date (Print):October 1, 1994Publication History Published online1 May 2002Published inissue 1 October 1994https://pubs.acs.org/doi/10.1021/ma00100a034https://doi.org/10.1021/ma00100a034research-articleACS PublicationsRequest reuse permissionsArticle Views128Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

This paper describes a novel method for measuring golf swing angular motion in a global coordinate system using the 3-D acceleration and angular velocity detected by a local motion sensor set at the grip end of a golf club. Optical direct linear transformation (DLT) is the conventional method for measuring sports motion; however, accurate localization of global coordinates and precise setting of infrared high-speed cameras in the test field are essential. Furthermore, infrared reflectors must be attached to the moving object. The system itself and the fine-tuning are expensive, but an accurately set system can provide precise positions for the moving reflectors. It is effective for measuring translational motion but not angular motion that is based on the principles of measurement. The alternative method that is proposed here is easier in terms of setting and fine-tuning, more reasonable in cost, and more accurate in measuring rotational motion compared with the DLT method. Furthermore, the system's wireless transmitter enables noninvasive measurement. When addressing the golf club, its initial angles and posture matrix are calculated using the 3-D acceleration; when the swing begins, the motion sensor measures the changing angular velocity and the acceleration. The application of step-by-step Euler transformation for each sampling interval yields the angular velocity and angle in the global coordinate system. The mean RMSE of ten trials with five subjects was 3.06°, 26.64°, and 4.43° for the 3-D angle of the club shaft.

The temporal resolution of X-ray tomography, using a synchrotron radiation X-ray source, has been improved to millisecond order in recent years. However, the sample must be rotated at a speed of more than a few thousand revolutions per minute, which makes it difficult to control the environment around the sample. In this study, a high-speed rotation device has been developed, comprising two synchronized coaxial motors movable along the direction of the axis, which can stretch or compress the rotating sample. Using this device, tomograms of breaking rubber were successfully obtained at a temporal resolution of 10 ms.

Epoxidized natural rubber (ENR) was grafted with imidazolium ions, giving the materials self-healing and reprocessing properties. These imidazolium ions in the form of neutral ionic repeating units transformed the polyisoprene-based polymer chains into ionomers. Fourier transform infrared (FTIR) spectroscopy and solid-state nuclear magnetic resonance (NMR) analyses were carried out to confirm various interactions between ENR and 1H-imidazole. In particular, dynamic hydrogen bonding and the formation of ionic aggregates led to superior mechanical strength (tensile strength, ∼4.5 MPa; elongation at break, ∼700%), self-healing efficiency (90% in terms of elongation), and reprocessability of the resulting compound. Furthermore, the material exhibited excellent transparency with a normalized transparency of 90 ± 0.7% at a typical thickness of 0.5 mm. The visualization and the stability of the healing processes were confirmed by scanning electron microscopy (SEM) and confocal microscopy analyses. Finally, temperature scanning stress relaxation (TSSR) studies were carried out to identify the different types of stress relaxation behavior of the material and the effects of various noncovalent interactions on the high-temperature stability of the compounds. These studies could assist to gain significant insight into natural rubber-based advanced materials for sustainable development.

Abstract The mechanical properties of styrene‐butadiene rubber (SBR) vulcanizates prepared using various plasticizers including liquid polybutadiene and styrene‐butadiene copolymers were investigated. The effect of the liquid polymers as the plasticizers on the mechanical properties of the polymers, such as the hardness, tensile storage modulus, tanδ, and the modulus at 100% elongation values, were determined before and after the thermal aging. As a result, it was revealed that the use of these liquid polymers gave less amount of change in the measurement values for the mechanical properties during the aging. The crosslinking density and the amount of free polymers were also determined on the basis of the swelling and extraction data, respectively, using several organic solvents. These results support the fact that the added liquid polymers are fixed to the SBR networks. We revealed the superiority of the liquid styrene‐butadiene copolymers as the plasticizer, which provides sufficient mechanical properties after vulcanization and the excellent maintenance of the properties during the thermal aging process. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

In order to clarify the filler effect on rubbers, rheo-optical measurements were performed for unfilled and filled samples of a styrene–butadiene rubber/silica system. Refractive index matching was performed to increase transparency of samples and to reduce form birefringence of particles. The component stress of matrix rubber and the filler was successfully determined by using the strain-induced birefringence data. Our results were consistent with the composite model in micromechanics if the vitrified rubber layer is consider on the surface of fillers. On the basis of the experimental results, we proposed a phenomenological equation for large tensile properties for ideal filled rubbers.

Large-eddy simulations are conducted for a rotating golf ball and a rotating smooth sphere at a constant rotational speed at the subcritical, critical and supercritical Reynolds numbers. A negative lift force is generated in the critical regime for both models, whereas positive lift forces are generated in the subcritical and supercritical regimes. Detailed analysis on the flow separations on different sides of the models reveals the mechanism of the negative Magnus effect. Further investigation of the unsteady aerodynamics reveals the effect of rotating motion on the development of lateral forces and wake flow structures. It is found that the rotating motion helps to stabilize the resultant lateral forces for both models especially in the supercritical regime.

Natural rubber (NR) is synthesized by the rubber transferase (RTase) on rubber particles (RPs) in latex. Due to the heterogeneity of the RPs in latex, it is difficult to precisely characterize the RTase activity. In this study, we separated the RPs of Hevea brasiliensis with different particle size distributions, via stepwise centrifugations. Analyses of protein compositions and size distributions of NR in the RPs suggest that RPs in Hevea latex can be categorized into two distinct subclasses, the larger RPs (termed 1kRP, 2kRP, and 8kRP) and the smaller RPs (termed 20kRP and 50kRP). Precise enzymatic assays using the RPs revealed that 50kRP showed the highest RTase activity, whereas the larger RPs, which had been regarded to have quite low activity, also exhibited a comparable activity to the smaller RPs. Immunological detections of cis-prenyltransferases in the RPs showed that the abundance of these enzymes correlates with the extent of RTase activity.

We report the in situ structures and dynamics of hydrogenated polybutadiene (PB) chains bound to carbon black nanoparticle surfaces in polymer solutions composed of deuterated PB and deuterated toluene using small-angle neutron scattering and neutron spin-echo techniques together with molecular dynamics (MD) simulations. The experimental results showed that the swollen bound polymer chains exhibit the collective dynamics (the so-called breathing mode) at polymer concentrations (c) below and above the overlap polymer concentration (c*) (i.e., 0.61 < c/c* < 1.83), where the concentration profiles of the bound polymer remained unchanged with the different c values. Interestingly, the collective dynamics slowed down by a factor of 2 compared to that in pure d-toluene when the chain lengths of the bound polymer and matrix polymer were equal. However, when the free polymer chains were longer than the bound polymer chains, the decrease in collective dynamics was not as significant. MD simulations were performed to explore the interfacial event as a whole. As a result, we found that the matrix polymer chains, whose length is equal to that of the bound polymer, can be accommodated in the bound polymer layer effectively and are “strangulated” by the bound polymer chains, while the longer matrix polymer chains only partly penetrate into the bound chains and the diffusion behavior was hardly affected compared to that in bulk.

Circulating tumor cells (CTCs) have been a focus of study for metastatic cancer diagnostics, in <italic>in vitro</italic> anti-cancer drug screening to decide the chemotherapeutic course, and cancer biology research.