Poly description

Emulsion Polymerization. Poly(vinyl acetate)-based emulsion polymers are produced by the polymerization of an emulsified monomer through free-radicals generated by an initiator system. Descriptions of the technology may be found in several references (35—39). 

Poly(ethyl methacrylate) (PEMA) yields truly compatible blends with poly(vinyl acetate) up to 20% PEMA concentration (133). Synergistic improvement in material properties was observed. Poly(ethylene oxide) forms compatible homogeneous blends with poly(vinyl acetate) (134). The T of the blends and the crystaUizabiUty of the PEO depend on the composition. The miscibility window of poly(vinyl acetate) and its copolymers with alkyl acrylates can be broadened through the incorporation of acryUc acid as a third component (135). A description of compatible and incompatible blends of poly(vinyl acetate) and other copolymers has been compiled (136). Blends of poly(vinyl acetate) copolymers with urethanes can provide improved heat resistance to the product providing reduced creep rates in adhesives used for vinyl laminating (137). 

In this contribution, we discussed effects of disorder on the electronic properties of quasi-one-dimensional Peierls systems, like the conjugated polymer fraus-poly-acetylene. Since polymer materials generally are rather disordered and the effect of disorder on any quasi-one-dimensional system is strong, a proper description of these materials requires consideration of such effects. 

U. Rauscher, H. Basxler, D.D.C. Bradley, M. Hcnnecke. Excilon versus band description of the absorption and luminescence spectra in poly(/ -phenylcnevinylcne), Phys. Rev. 11, 1990, 42, 9830. 

Poly (p-nitrophenyl acrylate)-coated wide-pore glass (WPG) was also used as an activated carrier for the immobilization of biospecific ligands and enzymes, A detailed description of properties of these sorbents and catalysts as well as some specific features of their functioning is given in Sect. 6. 

Water occurs in glass-ionomer and related cements in at least two different states (Wilson McLean, 1988 Prosser Wilson, 1979). These states have been classified as evaporable and non-evaporable, depending on whether the water can be removed by vacuum desiccation over silica gel or whether it remains firmly bound in the cement when subjected to such treatment (Wilson Crisp, 1975). The alternative descriptions loosely bound and tightly bound have also been applied to these different states of water combination. In the glass-poly(acrylic acid) system the evaporable water is up to 5 % by weight of the total cement, while the bound water is 18-28 % (Prosser Wilson, 1979). This amount of tightly bound water is equivalent to five or six molecules of water for each acid group and associated metal cation. Hence at least ten molecules of water are involved in the hydration of each coordinated metal ion at a carboxylate site. 

A.P. de Weyer, L.M.C. Buydens, G. Kateman and H.M. Heuvel, Neural networks used as a soft modelling technique for quantitative description of the inner relation between physical properties and mechanical properties of poly ethylene terephthalate yams. Chemom. Intell. Lab. Syst., 16(1992) 77-82. 

Such weaknesses of the present implementation include the lack of an explicit inclusion of intermolecular forces other than excluded volume, resulting in a qualitatively inaccurate description of the equation of state. Another weakness is that the model shows lattice artefacts when dealing with problems of polymer crystallization or liquid-cristalline order only rather flexible poly-... 

In a typical reaction 100 - 200 mg of metal [Cr or Ni] was evaporated from a preformed alumina crucible over a period of 60 - 90 min and deposited into a mixture of 2 in poly(dimethylsiloxane) [Petrarch Systems 0.1 P.] within a rotary solution metal vapor reactor operating at 10 4 torr. The reaction flask was cooled to approximately 270 K by an iced-water bath. For a description of the apparatus see Chapter 3 of reference 4. The product in each case was a dark orange viscous liquid and was characterized as obtained from the reaction vessel. 

Figure 3.77 (a) The cycloaliphatic monomer subunits employed by Wegner and Riihe (1989). n varied between 3 and 10. (b) Schematic description of the poly pyrrole backbone wrapped in a layer of poorly conducting methylene moieties of the alkylcne chains fused to the pyrrole units in the 3,4 positions. The minimum separation distance, R, between adjacent chains can be estimated from molecular models. From Wegner and Riihe (1989). 

The Lines approximation is expected to be quite accurate for the description of the exchange interaction between a strongly axial doublet and an arbitrary isotropic spin. For all other cases, the Lines model [84] is a reasonable approximation. Efficient implementation of the Lines model was done in the program POLY ANISO. 

Hoftyzer and van Krevelen [100] investigated the combination of mass transfer together with chemical reactions in polycondensation, and deduced the ratedetermining factors from the description of gas absorption processes. They proposed three possible cases for poly condensation reactions, i.e. (1) the polycondensation takes place in the bulk of the polymer melt and the volatile compound produced has to be removed by a physical desorption process, (2) the polycondensation takes place exclusively in the vicinity of the interface at a rate determined by both reaction and diffusion, and (3) the reaction zone is located close to the interface and mass transport of the reactants to this zone is the rate-determining step. 

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