Coordination polymers INDEX

In this small survey, we have mainly used the Chemical Abstracts database to get some clarity concerning the origin of some words and how they have evolved. Some terms, such as coordination polymer, have been around for a while. Others have just started to appear, one example being metal-organic frameworks. Note that our statements of first usage or similar phrases means that they have appeared in the title, abstract, index terms or equivalent searchable information. These words most likely appeared earlier in the bulk text of articles but this is much more difficult to trace. 

Ethylene Polymers. Depending on the polymerization conditions, three major types of polyethylene are manufactured low-density polyethylene (LDPE) by free-radical polymerization, linear low-density polyethylene (LLDPE) by copolymerization of ethylene with terminal olefins, and high-density polyethylene (HDPE) by coordination polymerization. The processes yield polymers with different characteristics (molecular weight, molecular weight distribution, melt index, strength, crystallinity, density, processability). 

CAS CHEMICAL REGISTRY 8,000,000 compounds CHEMICAL ABSTRACTS SERVICE The world s largest file of substance information, including coordination compounds, polymers, incompletely defined substances, alloys, mixtures, and minerals. In each record, the registry number is linked to molecular structure diagram, molecular formula, CA index name, synonyms, and the ten most recent references in Chemical Abstracts. Easy crossover to the bibliographic file... 

Example 12.2 Coat Hanger Die Design We specify the coat hanger die manifold radius along the entire width of the die, if the manifold axis is straight and makes an angle a = 5° with the x coordinate (see Fig. 12.29). The slit opening is set at H — 0.05 cm, the half-width W = 100 cm, and the Power Law index of the polymer melt n — 0.5. 

Polyolefins have a central position in the marketplace of synthetic polymers, in terms of annual production volume . In the 1960s, Natta and coworkers reported that syndio-enriched polypropylene could be prepared by polymerization of propylene at —78°C in the presence of a mixture of vanadium tetrachloride and Et2AlCl . The molecular weight increased steadily for 25 h, and the polydispersity index (1.4 < My /M < 1.9) was moderately low °. This was the first hint of a possible control on this type of coordinative polymerization. 

Structure and data storage is shown on the right. A structure table contains the structures, their internal identifiers, and their external identifiers, if any. The structures are stored in a compact binary representation that includes the connection table, the coordinates, the ring information, and any stereochemical, valence, isomer, isotope, or bond information. Certain types of structure-specific information such as polymer or component designations are stored here, whereas other types of structure-specific information (atom- or bond-specific data, and more verbose text data) are stored in their own tables, referenced by the internal identifier, and the atom or bond numbers to which the data correspond. A formula table contains the molecular formula and various atom and atom-type indexes to enhance formula searching and sorting. 

For some applications, a refractive index is important. A match between the particle size of some barium grades and the refractive index of matrix material allows the formulation of products with desirable optical properties. A series of synthetic barium sulfates is produced by Sachtleben Chemie which have particle sizes between 4 and 10 pm. If the particle size of these barium sulfates is well coordinated with the refractive index of the matrix polymer, semi-opacity combined with translucency results. This permits the foimulation of a light disperser in lampshades or in illuminated advertising displays. The coirect particle size can be calculated from the equation d = (lOOn - 141)/2, where n is the refractive index of the resin and d the particle size of barium sulfate. 

Below it will be shown that in polymer fluids the slope in (log viscosity vs. log shear rate) coordinates, such as in Figure 17.1, is always negative (see Fig. 17.2). The more negative the slope, the lower the coefficient, showing how much the polymer fluid is deviating from behavior of the Newtonian fluid. For a Newtonian fluid this coefficient, which is called the power-law index, is equal to 1. For some moderately non-Newtonian fluids, the power-law index is equal to 0.9-0.8. For strongly non-Newtonian fluids, it is equal to 0.2-0.3. 

For most of the semicrystalline polymers that have been synthesized and studied to any extent to date the unit cell parameters are known at least approximately, and a good tabulation of such data is found in reference books such as Polymer Handbook.11 When the unit cell geometry is entirely unknown, indexing the Bragg reflections is a more involved process. Having a fiber diagram rather than a powder diagram alone is then useful, since the two-dimensional information about the x and y coordinates of... 

All the physical quantities of a polymer system can be expressed through the statistical integrals with an imposed constraint. The fixing of several p points relating to the given macromolecules may serve as such a constraint. Each of the point, called a correlation point, is denoted by the index q (1 < q < p). The point with the index q is assumed to relate to the chain jg wjth the area Sg, and the coordinate of the point along the chain is s, (0 < s, < 5,), its spatial position is characterized by the vector r,. The imposed constraint implies that the condition... 

Bulk moduli for ambient conditions (with index o ) are listed in Tables 10.7 for elements, SlO.l for compounds MX, S10.2 for MX2, S10.3 for MX3, S10.4 for binary oxides, S10.5 for binary nitrides, S10.6 for binary borides, S10.7 for binary carbides and silicides, S10.8 for binary phosphides and arsenides, S10.9 for ternary oxides and coordination compounds, SIO.IO for molecular substances and polymers, SlO.l 1 for characteristics of polymorphous modifications of elements and the MX compounds, S10.12 for various phases ofMX2 crystals. 

The method of choice for the determination of these quantities on HDPE resin is gel permeation chromatography. In this chromatographic method a solvent with the dissolved polyethylene flows through a column filled with a porous material. It is usually a gel of cross-linked polymers. Depending upon the size of the polyethylene coils in the solution, they can fit to the pores of the gel, stick there and block them whereby the transport is retarded. Larger polyethylene chains are transported unhindered with the solvent flow. Thus a size-dependent retardation occurs which justifies the other term size exclusion chromatography (SEC). In the chromatogram, which shows polymer concentration (determined for example via optical measurements (refractive index)) as a function of time, the time coordinate corresponds to a polymer molecular mass coordinate and the concentration... 

When SRUs are bridged only by metals, systematic polymer nomenclature is not used instead, the substance is indexed either at the monomeric salt name or by coordination nomenclature, with a modification phrase, in either case, such as homopolymer or pol5mier with... (2). 

Each element is labeled by the vector m = (i,j, k), and the element nodes are numbered by the index = 1 — 8 and characterized by the coordinates r (m) [3]. Within each element m, the concentrations of the dissolved reagent u(m), the oxidized metal-ion catalyst u(m), and the volume fraction of polymer < (m) are taken to be spatially uniform. The latter value is related to the volume of the element V(m) as 0(m) = A < o/T(m). Within each element, we introducealocal coordinate system (, , f) as shown in Figure 8.1a. We then calculate the coordinates within the element m in this local coordinate system through the values of the nodal coordinates r (m) and a set of shape functions, as detailed in Refs. [37, 38). We perform aU the necessarily volume and surface integrations within each linear hexahedral element in this local coordinate system [3]. 

At diffusion MS from films, also as well as in case of sorption by films ChT-AM of water vapor, have anomalously low values of the parameter n, estimated in this case from the slope in the coordinates lg(G/G )-lgt. Increase the concentration of MS and time of isothermal annealing, as well as in the process of sorption of water vapor films, accompanied by an additional decrease in the parameter n. sym-biotically index n also changes magnitude a. Moreover, the relationship between the parameters of water sorption films ChT-AM (values of diffusion coefficient, an indicator n and values of equilibrium sorption Q) and the corresponding parameters of the diffusion of MS from the polymer film on condition G/G < 0.5 is shown. 

In terpolymerizations with MA, where two azeotropic copolymer pairs can be formed, Slocombe described an azeotropic copolymer index. In the method, the monomer-terpolymer composition plots take the form of a triangular coordinate graph. A line connecting the points that represented the composition along the azeotropic line have unique properties, i.e., give clear terpolymers, whereas compositions removed from the line gave increasingly turbid polymers as their distance from the azeotropic line increased. 

Conjugated polymers (143) have also been prepared via coordination of iron(II) to dUithio >i5(3-hexyl-4-methylcyclopentadienide)arylenes (142) (Scheme 38)." " The weight average MW of these polymers were between 42,000 and 52,600 with polydispersity index (PDI) values ranging fiom 10.5 to 14.6. Oxidation of these polymers resulted in electrical conductivities ranging from 10 to 10 S/cm. 

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