bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon—Silica Dual Phase Filler, A New Generation Reinforcing Agent for Rubber: Part VIII. Surface Characterization by IGC
Authors: Wang Meng-Jiao , Tu Hairuo , Murphy Lawrence J. , Mahmud Khaled 
Published: February 2011

Abstract
The surface characteristics of carbon—silica dual phase filler (CSDPF) were investigated by inverse gas chromatography (IGC) at infinite dilution. It was found that due to its unique surface microstructure, the dispersive component of the surface energy γsd of CSDPF is considerably higher than those of carbon black and silica. Among CSDPFs, the surface energies increase with increasing surface area. The adsorption energies of a series of hydrocarbon probes and polar compounds were also measured with IGC. Relative to conventional fillers, the higher adsorption energies of hydrocarbon probes on dual phase fillers as well as their higher γsd, suggest a stronger interaction with hydrocarbon polymers. This is consistent with observations on bound rubber measurement. The overall polarity of CSDPF and the specific or polar component of the surface energy of CSDPF were estimated from specific free energies of adsorption of polar compounds. The polarity of this new filler, while being similar to that of its carbon black counterpart, is substantially lower than the polarity of precipitated silica. This would result in a high compatibility of this dual phase filler with hydrocarbon rubber, leading to lower filler—filler interaction and better microdispersion.
Kinetic Analysis of the Thermal Degradation of PP—EPDM Blends
Authors: López-Manchado Miguel , Torre Luigi , Kenny JoséM. 
Published: February 2011

Abstract
The thermal degradation of polypropylene (PP)/ethylene—propylene—diene rubber (EPDM) and their blends is presented. In order to evaluate the effect of the components on the thermal stability, the degradation kinetics of blends of different composition is analyzed by thermogravimetry in isothermal and constant heating rate conditions in pure nitrogen. The Flynn and Wall method is used to obtain the activation energies from the dynamic tests, while isothermal test results are used to determine the pseudo order of reaction and the shape of the ƒ(α) function which is similar to an autocatalytic type equation. Model parameters such as activation energies and pseudo order of reaction are calculated using a non-linear regression analysis. Although PP—EPDM blends are not compatible, the degradation process was not clearly characterized by two independent reactions, suggesting that both components are interacting during degradation. Moreover, the kinetic study showed that the activation energy of the whole degradation process changes linearly with the relative amount of the components; on the other hand, small differences were observed in the reaction orders.
The Chemistry of Phenol-Formaldehyde Resin Crosslinking of EPDM as Studied with Low-Molecular-Weight Models: Part II. Formation of Inert Species, Crosslink Precursors and Crosslinks
Authors: van Duin Martin 
Published: February 2011

Abstract
Phenol-formaldehyde resins (resols) are the preferred crosslinking agents for the dynamic vulcanization of blends of polypropylene and ethylene—propylene—diene rubber (PP/EPDM) for the production of thermoplastic vulcanizates (TPVs). The goals of this study were to elucidate in detail the chemical structures formed using low-molecular-weight model compounds and to elaborate on the chemical mechanism of resol cure of EPDM as presented in our previous study. The use of model compounds for EPDM (2-ethylidenenorbornane [ENBH] and 4-methylheptane), but also for resol (2-hydroxymethylphenol [HMP] and 2,6-di(hydroxymethyl)-p-cresol) allowed the characterization of the chemical structures formed with the aid of gas chromatography/mass spectrometry (GC/MS). In combination with derivatization of unreacted hydroxyls a large variety of species could be distinguished with the general structure of R−phenol-[-CH2−phenol-]n−R′ (n=0, 1 or 2). R and R′ can be inert end groups resulting from degradation or disproportionation, viz. —H, —CH3 or —CHO, reactive end groups, viz. —CH2OH, and products of addition to ENBH (C9H14), viz. —CH2—C9H13. When either R or R′ is —CH2—C9H13 a model crosslink precursor is formed, when both are —CH2—C9H13 a model crosslink is formed. It has been demonstrated beyond doubt that both chroman and methylene bridged species are produced. It is still unclear what parameters determine the selectivity for chroman versus methylene bridged structures (presence of activators, structure of olefin etc.). The two major model crosslink products of HMP and ENBH have also been characterized with nuclear magnetic resonance, which confirmed the chroman and methylene bridged structures and showed that the addition of the phenol predominantly occurs at the least sterically hindered C-8 of ENBH. The yield of the reaction of resol with ENBH is enhanced by temperature increase and/or the addition of SnCl2·2H2O. 4-Methylheptane does not react with HMP. This indicates that in a PP/EPDM based TPV only crosslinking of EPDM via the residual diene unsaturation occurs and that tertiary C-atoms of PP or of the ethylene—propylene rubber (EPM) chain of EPDM are not involved. The high reactivity of ENBH compared with 1-decene or hydrogenated dicyclopentadiene supports a cationic mechanism.
New Emulsion SBR Technology: Part I. Raw Polymer Study
Authors: Lewandowski Laurand , Sibbald Morgan S. , Johnson Ed , Mallamaci Michael P. 
Published: February 2011

Abstract
Emulsion styrene—butadiene rubber (ESBR) has been the workhorse of the tire industry since World War II. With the development of solution polymers, ESBR has seen a steady decrease in its use in tire applications. A novel ESBR has been developed which imparts some of the rheological behavior previously only observed in solution polymers. This new ESBR was prepared by blending a high molecular weight elastomer with a low molecular weight elastomer, each having a unique styrene-butadiene composition. A two-phase co-continuous morphology was observed by scanning probe microscopy when the bound styrene difference between the two components was greater than 18%, consistent with the two glass transition temperatures measured by thermal analysis. Blending also served to reduce the amount of very high molecular weight material (&gt; 107 g/mol) readily observed in 1502- and 1712-type polymers by thermal field flow fractionation (ThFFF). ThFFF was found to be superior to size exclusion chromatography for fully characterizing the molecular weight and molecular weight distribution of the polymers. Time—temperature superposition was performed to characterize the viscoelastic behavior in the rubbery plateau and terminal zones. The ESBR blends showed a cross-over in the terminal flow region that was not observed in 1502- and 1712-type polymers.
The Effect of Composition and Processing Conditions on the Structure Development in Injection Molded Dynamically Vulcanized PP/EPDM Blends
Authors: Cakmak M. , Cronin S. W. 
Published: February 2011

Abstract
The effect of composition and processing conditions on the spatial structural variation in dynamically vulcanized injection molded poly(propylene)/ethylene—propylene—diene rubber (PP/EPDM) was investigated using matrixing microbeam X-ray system and transmission optical microscopy techniques. The structure gradient in the thickness direction in these samples is composed of very thick, highly oriented, skin regions followed by core regions of lower preferential chain orientation. In these samples, the shear-crystallized layers are observed to be much thicker than the comparably processed pure PP. The nucleation densities in the PP phase were too high to allow for observation of individual crystallites in most of the regions except near the very core, where sparsely distributed PP crystallites, that appear bright under cross polars, were observed. The wide-angle X-ray scattering (WAXS) patterns taken at different distances from the skin indicate that chain axes are mostly oriented in the flow direction, and distinct bimodal c-axis and a* axis oriented dual population of orientation is observed in the PP phase. c-axis orientation factors, fc, start at intermediate values at the skin and increase steadily and after showing a maximum roughly in the middle of the shear crystallized region, decrease towards the core, and in most cases never achieve a state of isotropy. In the blends that contain very small polypropylene fractions (ca ∼ 15%), unusually high orientation levels were observed. This was attributed to the “shear amplification” phenomena that dominates the thin PP regions between the rubber particles and causes significant orientation levels in the thin layers of PP coating, the rubber particles with the relative motion of the particles in the shear flow field.
High-Speed Fracture of Elastomers: Part I
Authors: Lake G. J. , Lawrence C. C. , Thomas A. G. 
Published: February 2011

Abstract
The fracture behavior of elastomers has been studied in the high speed region immediately above a transition region where a change in the nature of the fracture surface occurs. A video camera operating at up to 6000 frames/s was used to follow the progress of failure. The test pieces employed were of the pure shear or tensile strip (with edge crack) varieties employed in earlier tear studies; in order to attain the high energy release rates required they were usually pre-strained and then cut to initiate the crack growth. The materials studied included various strain crystallizing and non-crystallizing elastomers, with different glass-transition temperatures, including natural rubber in normal, cis—trans isomerized or partially-epoxidized forms, a butadiene—acrylonitrile copolymer, a styrene—butadiene copolymer and ethylene—propylene co- and ter-polymers. The use of a fracture mechanics approach based on the strain energy release rate enables results for different test piece geometries to be brought into agreement in the region above the transition. Fracture energies in this region correlate well with viscoelastic properties, but the potential for strain crystallization to strengthen is not exhibited. This is presumably because at the high failure rates involved, the loading time at the crack tip is insufficient to allow significant crystallization to occur. The correlation with viscoelastic behavior suggests that the material around the propagating tip is still essentially rubbery in its behavior, although the fracture surfaces in the high speed region have a smooth, “glassy” appearance. Further evidence of this is provided by effects of crosslink type and density and filler type and loading, where again the effects seen in the high speed failure region parallel those observed below the transition. An effect of thickness on fracture properties appears to be absent in the high speed region, by contrast with behavior at lower energies and at the transition itself. This supports the view that the fracture surface roughness that develops in the lower energy region is due to the initiation of a process akin to cavitation by through-the-thickness stresses near the crack tip. The transition is found to vary with pressure and temperature, as well as thickness, in a way that does not correlate with viscoelastic changes but may reflect changes in the through-the-thickness stresses. The existence of a limiting crack speed is illustrated and discussed. Fracture under large biaxial deformations, where higher crack speeds are observed, will be discussed in Part II.
A New Class of Thermoplastic Elastic Polypropenes Prepared with a High Activity “Dual-Side” Zirconocene Catalyst
Authors: Dietrich Ulf , Hackmann Martijn , Rieger Bernhard 
Published: February 2011

Abstract
It is well known that the mechanical properties of highly isotactic polypropene depend on the crystalline structure of the material. Up to now, the polymer properties were modified by varying either the processing conditions—e.g., extrusion, annealing etc.—or the composition—e.g., blending, nucleation. Highly active ethylene bridged C1-symmetric zirconocene catalysts can be used to design the material properties by varying the crystallinity of thermoplastic (elastic) polypropenes. With the new unsymmetric catalyst rac−dichloro[1−(9−fluorenyl)−2−(R,S)−(5,6−cyclopenta−2−methylinden−1−η5−yl)ethane]zirconium (IV)/MAO (1) polypropenes of variable isotacticities are accessible. The variable and thus defined use of two different sides of the catalytically active species allows the placement of single, cumulated and consecutive [rr]-triads within an isotactic polymer chain. The formation of these stereoerrors is adjusted in an arbitrary manner by the polymerization conditions temperature and monomer concentration. The mechanical properties of polypropenes produced with 1/MAO vary from tough thermoplastic to excellent elastic. Stress—strain behavior of these physically crosslinked elastomers can be designed similar to the ones of polyisoprene or partly crosslinked natural rubber.
Crystallization in Natural Rubber. II. The Influence of Impurities
Authors: Gent A. N. 
Published: February 2011

Abstract
Experiments are described in which the effect of the presence of foreign substances on the rate of crystallization of natural rubber at −26° C is examined. It is shown that small amounts of suitable impurities, some of which are present in smoked sheet and other plantation rubbers, accelerate the crystallization process markedly at this temperature, presumably by promoting crystal nucleation.
Benzofuroxans as Rubber Additives
Authors: Graves Daniel F. 
Published: February 2011

Abstract
Benzofurazan 1-oxide, commonly called benzofuroxan (BFO), was shown to decrease hysteresis of carbon black-filledrubber vulcanizates by as much as 30%. Presumably, BFO promotes increased bonding between the elastomerand carbon black resulting in reduced “Payne Effect” in the vulcanizate. BFO was added during the mixing of themasterbatch at various temperatures. It was found that high temperature mixing was necessary to achieve maximumhysteresis reduction and that more effect was noted with high surface area blacks. Nickel salts were found to modifythe reaction between BFO and the elastomer/black.
An iterative method for design of water‐using networks with regeneration recycling
Authors: Pan Chunhui , Shi Jing , Liu Zhi‐Yong 
Published: February 2011

AbstractBoth freshwater consumption and wastewater discharge can be reduced significantly when wastewater regeneration recycling is introduced in the design of the water‐using networks (WUNs). However, it is often difficult to design the WUNs involving regeneration recycling. This article presents an iterative method to design the WUNs involving regeneration recycling. The final designs can be obtained without iteration for the networks with known regenerated concentrations, and in a few iterations for the networks with known removal ratios of the contaminants. The method proposed can reduce the following parameters simultaneously, the consumptions of freshwater and the regenerated water, and the concentrations of the stream before regeneration, and all of them reflect the cost of the network involving regeneration recycling. The results of a few literature examples show that the designs obtained in this work are comparable to that obtained in the literature. The proposed method is simple and effective. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Rheology, crystallization behaviors, and thermal stabilities of poly(butylene succinate)/pristine multiwalled carbon nanotube composites obtained by melt compounding
Authors: Wang Guoli , Guo Baohua , Xu Jun , Li Rui 
Published: February 2011

AbstractPoly(butylene succinate) (PBS)/pristine raw multiwalled carbon nanotube (MWCNT) composites were prepared in this work via simple melt compounding. Morphological observations indicated that the MWCNTs were well dispersed in the PBS matrix. Moreover, the incorporation of MWCNTs did not affect the crystal form of PBS as measured by wide‐angle X‐ray diffraction. The rheology, crystallization behaviors, and thermal stabilities of PBS/MWCNT composites were studied in detail. Compared with neat PBS, the incorporation of MWCNTs into the matrix led to higher complex viscosities (|η*|), storage modulus (G′), loss modulus (G″), shear thinning behaviors, and lower damping factor (tan δ) at low frequency range, and shifted the PBS/MWCNT composites from liquid‐like to solid‐like, which affected the crystallization behaviors and thermal stabilities of PBS. The presence of a very small quantity of MWCNTs had a significant heterogeneous‐nucleation effect on the crystallization of PBS, resulting in the enhancement of crystallization temperature, i.e., with the addition of 0.5 wt % MWCNTs, the values of Tc of PBS/MWCNT composites could attain to 90°C, about 6°C higher than that of neat PBS, whereas the values of Tc increased slightly with further increasing the MWCNTs content. The thermogravimetric analysis illustrated that the thermal stability of PBS was improved with the addition of MWCNTs compared with that of neat PBS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Study on the flame retardancy of EVM/magnesium hydroxide composites optimized with a flame retardant containing phosphorus and silicon
Authors: Wang Lichun , Wu Xinfeng , Wu Chao , Yu Jinhong , Wang Genlin , Jiang Pingkai 
Published: February 2011

AbstractA novel phosphorus‐silicon‐containing flame retardant, spirocyclic pentaerythritol bisphosphorate disphosphoryl chloride/9, 10‐dihydro‐9‐oxa‐10‐phosphaphanthrene‐10‐oxide/vinyl methyl dimethoxysilane (SPDV), was synthesized successfully and used for optimizing the flame retardancy of ethylene‐vinyl acetate copolymer (EVM) rubber/magnesium hydroxide (MDH) composites. The microstructure of SPDV was characterized and determined by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. Thermogravimetric analysis (TGA) showed that SPDV had good charring effect in air even at high temperature (800°C). The flame retardancy of the optimized EVM/MDH composites by SPDV was investigated by limiting oxygen index (LOI), cone calorimeter, and UL‐94 vertical burning tests. A higher LOI value (29.4%) and better UL‐94 rating (V‐0) can be achieved for the optimized EVM/MDH composite (EVM‐7) than EVM/MDH composite without SPDV (EVM‐3) with the total loading of additives. The HRR decreased and residual mass increased gradually as the loading of SPDV increased for the optimized EVM/MDH composites. There existed distinct synergistic intumescent flame‐retardant effect between SPDV and MDH in EVM matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Surface characterization of quaternized polysulfone films and biocompatibility studies
Authors: Ioan Silvia , Albu Raluca Marinica , Avram Ecaterina , Stoica Iuliana , Ioanid Emil Ghiocel 
Published: February 2011

AbstractA novel quaternized polysulfone with N‐dimethyloctylammonium groups was investigated with respect to its surface properties, hydrophobicity, interactions with blood, and morphology. The history of the films formed from N,N‐dimethylformamide/methanol and N,N‐dimethylformamide/water solutions and the compositions of the solvent/nonsolvent mixtures influenced the surface morphology. Thus, atomic force microscopy investigations of the films showed pores and nodules of different sizes and intensities, which depended on the content of methanol or water in the solvent mixtures. Hydrophilicity modification, evidenced by the apolar components and the electron‐acceptor and electron‐donor parameters of the polar components of the surface tension parameters, was correlated with atomic force microscopy data. Surface wettability trends were analyzed on the basis of the free energy of hydration between the prepared films and water and the work of adhesion. The adhesion of red blood cells to the modified polysulfone showed the influence of the hydrophobic properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of glutaraldehyde on electrical properties of arrowroot starch + NaI electrolyte system
Authors: Tiwari Tuhina , Pandey K. , Srivastava Neelam , Srivastava P. C. 
Published: February 2011

AbstractA biopolymer based electrolyte system has been developed using NaI as dopant salt and Arrowroot starch as polymer matrix. Problem of fungal growth in such system has been removed by the addition of Glutaraldehyde (GA). The conductivity of the Arrowroot + NaI electrolyte system is of the order of 6.7 × 10−4 S cm−1. Starch without crosslinker GA seems to be highly unstable and prone to fungal growth whereas the GA crosslinked electrolyte is quite stable. Color of the material as well as its conductivity data indicate that presence of GA affects the salt dissociation and multiplets formation. Ionic transference number of system is ≥0.95 indicating that prepared system is ionic conductor/electrolyte. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Decision‐making Competence, Executive Functioning, and General Cognitive Abilities
Authors: Del Missier Fabio , Mäntylä Timo , de Bruin Wändi Bruine 
Published: February 2011

ABSTRACTAlthough previous studies investigated the relationship between general cognitive abilities and decision making, few have characterized specific cognitive abilities underlying decision‐making competence. In this paper, we focus on executive functions—control processes involved in the regulation of cognition. Specifically, we report on an individual‐differences study that investigated the relationship of executive functioning (EF) and general cognitive abilities (fluid intelligence and numeracy) with different aspects of decision‐making competence. Individual differences in EF components explained aspects of decision‐making competence even after controlling for fluid intelligence and numeracy. However, different aspects of decision‐making competence varied in the extent to which they relied on different executive functions. In particular, resistance to framing effects, the ability to apply decision rules, and successful engagement in cognitive reflection partially depend on individual differences on the monitoring/inhibition dimension of EF. The ability to provide consistent judgments in risk perception is related to the shifting aspect of EF. The ability to recognize social norms and resistance to sunk costs were not significantly related to EF, thus supporting the idea that executive control is not a major determinant of these aspects of decision‐making competence. Finally, substantial variance in some of the decision‐making tasks remained unexplained, suggesting that other cognitive or non‐cognitive abilities need to be considered in future studies. Copyright © 2011 John Wiley & Sons, Ltd.
Mutation detection in plasmid‐based biopharmaceuticals
Authors: Oliveira Pedro H. , Prather Kristala L. J. , Prazeres Duarte M. F. , Monteiro Gabriel A. 
Published: February 2011

AbstractAs the number of applications involving therapeutic plasmid DNA (pDNA) increases worldwide, there is a growing concern over maintaining rigorous quality control through a panel of high‐quality assays. For this reason, efficient, cost‐effective and sensitive technologies enabling the identification of genetic variants and unwanted side products are needed to successfully establish the identity and stability of a plasmid‐based biopharmaceutical. This review highlights several bioinformatic tools for ab initio detection of potentially unstable DNA regions, as well as techniques used for mutation detection in nucleic acids, with particular emphasis on pDNA.