Protecting-Group-Free Synthesis of Thiol-Functionalized Degradable Polyesters

Chemical Characterization Problems of Water-Soluble Polymers

Society of Petroleum Engineers Journal ◽

10.2118/8977-pa ◽

1981 ◽

Vol 21 (06) ◽

pp. 721-730 ◽

Cited By ~ 1

Author(s):

D.A. Tyssee ◽

O.J. Vetter

Keyword(s):

High Temperature ◽

Physical Properties ◽

Water Soluble ◽

Polymer Chemistry ◽

Petroleum Reservoir ◽

Polymer Backbone ◽

Water Soluble Polymers ◽

Soluble Polymers ◽

The Past ◽

Analytical Procedures

Abstract Water-soluble polymers are being used increasingly in oil, gas, and geothermal production. Applications include drilling, stimulation, workover and completion, and reservoir flooding fluids. The development of polymers and their application has been mostly empirical. Such a course of development was suitable in the past. However, empirical techniques do not satisfy present and future needs which include (1) the cost/performance relationship and (2) environmental effects associated with expanding polymer application. Therefore, a more thorough understanding of the polymer chemistry is required.The first step in doing this is to develop laboratory methods to characterize these complex materials and their degradation products. The problems are (1) understanding polymer chemistry under field conditions and (2) developing analytical procedures. These problems emerged dramatically during analysis of recent fracture stimulation of some geothermal wells. An involved study of the potential analytical methods was conducted. Polysaccharides were used for the actual field fracture jobs as well as for the analytical procedures. Correlations were made between the total organic content and carbohydrate content of the return waters as a function of residence time under simulated reservoir conditions. Preliminary indications are that more sophisticated information can be obtained by the use of emerging analytical techniques such as high pressure liquid chromatography (HPLC).Advantages gained from use of these methods and others are discussed. Introduction A variety of polymers are used in the petroleum industry for drilling, workover, and completion fluids. Many of these polymers can be used in the geothermal industry for similar applications. However, because the environment of a geothermal reservoir may be drastically different from that of a petroleum reservoir, it is critical that these polymers be investigated under conditions that simulate geothermal environments. In the past, physical property measurements of aqueous solutions of these polymers have been emphasized - particularly fluid rheology both for petroleum and, to a lesser extent, geothermal applications. These physical properties, which are valuable in selecting polymers or polymer blends for use, can be related to the chemical properties of the polymers. Properties such as molecular weight distribution and macrostructure, molecular conformation, side-chain structure, composition of the monomer units comprising the polymer backbone, chemical interactions in the make-up water, chemical and thermal stability, etc., play an important role in determining the ultimate physical properties of the polymer in solutions.Many of these chemical features have been overlooked, and the development of polymers for field applications has followed a strictly empirical course. This empiricism has led to a great deal of confusion when polymers must be selected for field use. A more serious drawback has been the lack of new polymer types - largely because little is known about how the physical properties desired can be related to polymer chemistry. This can be traced for the most part to the lack of chemical methods available in the past to characterize the polymers chemically in sufficient detail. The high-temperature requirements of geothermal applications impose severe limitation on the fracture polymers, particularly their performance and chemical stability under high-temperature conditions. SPEJ P. 721^

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The Photometric Properties of the Ap Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100080684 ◽

1976 ◽

Vol 32 ◽

pp. 365-377 ◽

Cited By ~ 2

Author(s):

B. Hauck

Keyword(s):

Physical Properties ◽

Ap Stars

The Ap stars are numerous - the photometric systems tool It would be very tedious to review in detail all that which is in the literature concerning the photometry of the Ap stars. In my opinion it is necessary to examine the problem of the photometric properties of the Ap stars by considering first of all the possibility of deriving some physical properties for the Ap stars, or of detecting new ones. My talk today is prepared in this spirit. The classification by means of photoelectric photometric systems is at the present time very well established for many systems, such as UBV, uvbyβ, Vilnius, Geneva and DDO systems. Details and methods of classification can be found in Golay (1974) or in the proceedings of the Albany Colloquium edited by Philip and Hayes (1975).

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The Infection of Cells by Bullet-Shaped Viruses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100063779 ◽

1969 ◽

Vol 27 ◽

pp. 372-373

Author(s):

Frederick A. Murphy ◽

Alyne K. Harrison ◽

Sylvia G. Whitfield

Keyword(s):

Electron Microscopy ◽

Physical Properties ◽

Host Cell ◽

Thin Section ◽

Cultured Cells ◽

Cell Infection ◽

Thin Section Electron Microscopy ◽

Section Electron ◽

Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

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Transmission electron microscopy of composite materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107125 ◽

1988 ◽

Vol 46 ◽

pp. 1012-1015

Author(s):

K.P.D. Lagerlof

Keyword(s):

Composite Materials ◽

Physical Properties ◽

Structural Defects ◽

Structural Composites ◽

Multiphase Materials ◽

Structural Reinforcement ◽

Transmission Electron ◽

Reinforced Fiber ◽

Particulate Reinforced Composites ◽

Definition Of

Although most materials contain more than one phase, and thus are multiphase materials, the definition of composite materials is commonly used to describe those materials containing more than one phase deliberately added to obtain certain desired physical properties. Composite materials are often classified according to their application, i.e. structural composites and electronic composites, but may also be classified according to the type of compounds making up the composite, i.e. metal/ceramic, ceramic/ceramie and metal/semiconductor composites. For structural composites it is also common to refer to the type of structural reinforcement; whisker-reinforced, fiber-reinforced, or particulate reinforced composites [1-4].For all types of composite materials, it is of fundamental importance to understand the relationship between the microstructure and the observed physical properties, and it is therefore vital to properly characterize the microstructure. The interfaces separating the different phases comprising the composite are of particular interest to understand. In structural composites the interface is often the weakest part, where fracture will nucleate, and in electronic composites structural defects at or near the interface will affect the critical electronic properties.

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Anisotropic Membranes as Substrates for Sem

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092189 ◽

1976 ◽

Vol 34 ◽

pp. 444-445

Author(s):

Thomas P. Turnbull ◽

W. F. Bowers

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Flow ◽

Polymer Chemistry ◽

Surface Porosity ◽

Transmission Electron ◽

Pore Texture ◽

Spongy Layer ◽

Scanning Electron

Until recently the prime purposes of filters have been to produce clear filtrates or to collect particles from solution and then remove the filter medium and examine the particles by transmission electron microscopy. These filters have not had the best characteristics for scanning electron microscopy due to the size of the pores or the surface topography. Advances in polymer chemistry and membrane technology resulted in membranes whose characteristics make them versatile substrates for many scanning electron microscope applications. These polysulphone type membranes are anisotropic, consisting of a very thin (0.1 to 1.5 μm) dense skin of extremely fine, controlled pore texture upon a much thicker (50 to 250μm), spongy layer of the same polymer. Apparent pore diameters can be controlled in the range of 10 to 40 A. The high flow ultrafilters which we are describing have a surface porosity in the range of 15 to 25 angstrom units (0.0015-0.0025μm).

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