ExxonMobil

About: ExxonMobil is a company organization based out in Irving, Texas, United States. It is known for research contribution in the topics: Catalysis & Polymer. The organization has 16969 authors who have published 23758 publications receiving 535713 citations. The organization is also known as: Exxon Mobil Corporation & Exxon Mobil Corp..

Structure and dynamics of carbon black-filled elastomers

Abstract: The linear and nonlinear melt viscoelastic properties for a series of carbon black-filled polymer composites were studied. Complementary tapping-mode atomic force microscopy (AFM) studies were used to examine the dispersion and structural correlations of the filler particles in these composites. The low-frequency dependence of the linear viscoelastic moduli gradually changes from liquidlike behavior for the unfilled polymer to pseudosolid character for composites with more than 9 vol % carbon black filler. The plateau modulus, inferred from the linear viscoelastic response, exhibits a somewhat discontinuous change at about 9 vol % filler. On the basis of the linear viscoelastic response, we postulate that the carbon black filler forms a continuous percolated network structure beyond 9 vol % filler, considerably lower than that expected from theoretical calculations for overlapping spheres and ellipsoids. We suggest that the lower threshold for percolation is due to the polymer mediation of the filler structure, resulting from the low functionality of the polymer and, consequently, few strong polymer–filler interactions, allowing for long loops and tails that can either bridge filler particles or entangle with one another. Furthermore, the strain amplitude for the transition from linear behavior to nonlinear behavior of the modulus for the composites with greater than 9 vol % filler is independent of frequency, and this critical strain amplitude decreases with increasing filler concentration. Complementary AFM measurements suggest a well-dispersed carbon black structure with the nearest neighbor distance showing a discontinuous decrease at about 9 vol % filler, again consistent with the formation of a filler network structure beyond 9 vol % carbon black. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 256–275, 2001

Hydrocarbon Conversion Process

Abstract: The invention relates to methods and equipment for converting C 3+ olefin to, e.g., one or more of di-C 3+ olefin, oligomers and polymers of C 3+ olefin, branched C 4+ -aldehydes, C 4+ -carboxylic acids, and C 4+ oxygenates. The invention encompasses producing methyl tert-butyl ether and diisobutylene, and converting methyl tert-butyl ether to isobutylene.

Hydrophobically associating terpolymers containing sulfonate functionality

Abstract: This invention describes novel hydrophobically associating terpolymers containing sulfonate functionality which are useful as aqueous fluid rheology or flow modifiers. These high molecular weight water soluble polymers contain both water soluble and water insoluble monomers. The water soluble monomers are acrylamide (AM) and a salt of an ethylenically unsaturated sulfonic acid (S) and the water insoluble monomer is a higher alkyl acrylamide (R). These polymers are referred to as SRAM. The process for their preparation relies on solubilizing the water insoluble monomer into an aqueous micellar solution containing one or more surfactants and the water soluble monomers. The surfactants are specifically selected to enable homogenous dispersion of the hydrophobic monomer(s) in the presence of anionic sulfonate containing monomers. Redox or free radical initiators are used to copolymerize both the water soluble and water insoluble monomers, forming terpolymers of ethylenically unsaturated sulfonic acids, alkylacrylamides and acrylamide. Aqueous solutions of these hydrophically associating polymers exhibit enhanced viscosification, reduced salt sensitivity and other desirable rheological properties found useful in a variety of applications.

Cylindrical microemulsions: a polymer-like phase ?

Abstract: The regions of stability of spherical, cylindrical, and lamellar phases of microemulsions are calculated within mean-field theory. In the cylindrical phase, thermal fluctuations determine a temperature dependent persistence length below which the cylinders are rigid (rod-like) and above which the cylinders are flexible (polymer-like). The length of the polymer-like chains depends on concentration and temperature. The radii of gyration of these flexible microemulsions are also calculated.