Polymers expandable

Many polymers expand with increasing temperature. This can be predicted with simple analytic equations relating the volume at a given temperature V T) to the van der Waals volume F and the glass transition temperature, such as... 

Pulp-like olefin fibers are produced by a high pressure spurting process developed by Hercules Inc. and Solvay, Inc. Polypropylene or polyethylene is dissolved in volatile solvents at high temperature and pressure. After the solution is released, the solvent is volatilised, and the polymer expands into a highly fluffed, pulp-like product. Additives are included to modify the surface characteristics of the pulp. Uses include felted fabrics, substitution in whole or in part for wood pulp in papermaking, and replacement of asbestos in reinforcing appHcations (56). 

After 1930, when the true nature of polymers was at last generally, recognised, the study of polymers expanded from being the province of organic specialists physical chemists like Paul Flory and physicists like Charles Frank became involved. In this short chapter, I shall be especially concerned to map this broadening range of research on polymers. 

NEW CONCEPT FOR THE METAL-AIR BATTERIES USING COMPOSITES CONDUCTING POLYMERS / EXPANDED GRAPHITE AS CATALYSTS... 

We believe that new type of conducting polymer / expanded graphite composite electrodes as gas-diffusion cathodes will find in perspective a practical application for some types of batteries and fuel cells. 

V.G. Khomenko, V.Z. Barsukov, A.S. Katashinskii and T.I. Motronyuk. New concept for the metal-air batteries using composites conducting polymers/ expanded graphite. This book. 

The plant is used to produce type A and type B of the polymer expandable polystyrene (EPS) in F = 5 grain size fractions each from a number of raw materials ( ). The availability of raw materials and the product storage capacity are assumed to be unlimited. The preparation stage is not limiting the production process... 

The polymers expand during irradiation even in the absence of significant stress. This expansion can be accounted for by the generation of gas pressure within the sample. The shape of the curves of deflection vs. time, the magnitude of the deflection, and the differences between materials can be explained by the relative rates of gas generation within and gas diffusion out of the samples. 

Most LLDPE produced worldwide is made into thin film, either melt blown or cast from the melt. Blown film is produced by extrusion of LLDPE melt through a circular die with a large diameter, up to 100-120 cm. and a narrow gap, usually less than 1 mm. The tube of molten polymer expands from internal air pressure and forms a bubble of a larger diameter, Typically, the blow-up ratio, the ratio of the final film tube diameter to the circular-die diameter, is between 1.5 1 and 4 1. LLDPE cast film is manufactured by depositing potymer melt on a rotating heated... 

The intrinsic viscosities of the dendritic polymers are extremely small compared with those of linear polymer of the same MW [86,91]. Furthermore, the dendritic polymers expand very little in going from a 0 solvent to a good solvent [92]. This is to be expected. When steric congestion forces the polymer chains to expand in a 0 solvent, further expansion in a good solvent is limited. In this regard it is important to note that the 0 condition must be carefully specified. It is known that branched polymers have different 0 conditions to the linear counterpart [93]. 

Because protein and cellulosic fibers are buried in contact with copper metal objects, a chemical microsystem is established whereby the degradation of the fiber and the corrosion of the metal interact physically and chemically. As the corrosion solution impregnates and swells the fibers, polymer molecules in amorphous areas are spread apart but are prevented from complete dissolution by the resistant crystalline segments. Copper ion from the corrosion solution is bound to the polymers (Figure 5). As the fiber degrades and more end groups are formed, more copper is bound. Polymers expand further apart as interchain forces are reduced. 

The polymer expands to take the shape of the cooled mold and solidifies while air pressure remains in the part (third diagram from the top of Figure 14-58). After cooling, the mold halves open, the part is ejected (bottom diagram) and the next preform enters the mold. 

Synthetic polymers are arguably the most important materials made by chemists and used in modem society. Chapter 30 Synthetic Polymers expands on the foundations of polymers discussed in earlier Chapters 15 and 22. Of significance is emphasis on the environmental impact of polymer synthesis and use, discussed in sections on Green Polymer Synthesis (30.8), Polymer Recycling and Disposal (Section 30.9A), and Biodegradable Polymers (Section 30.9B). 

Metabolic pathway engineering has numerous applications in food, agriculture, chemical, and pharmaceutical industries. Examples include, but are not limited to, increasing the yield of antibiotics, biosynthetic precursors, or polymers, expanding the metabolic capacity to degrade harmful compounds, or producing novel compounds that cannot be found in nature. 

Increasing the temperature increases the selectivity of the reaction. This can be explained by the fact that the hot solvent (isopropanol) makes the polymer expand and then "core" sites can be reached by the substrate. There, cavities have a better defined shape making the system more selective. Therefore reaction should be performed at 60°C rather than at room temperature. The swelling-selectivity relationship is not absolute, the use of a very polar solvent such as N,N-dimethylacetamide, leads to such a swelling of the polymer that no more selectivity is observed Thus, one can assume that this increase of selectivity is due to an... 

The silica-based mineral opal may be considered a solid emulsion when enough water is trapped to have microscopic domains larger than the usual hydration layer. A solid foam coffee cup, thermos, or packing filler is made from polymer expanded with microscopic air pockets. Porous polymer and ceramic mem-... 

Now in its second edition, the book has been reviseSFand expanded to reflect recent developments in the subject. There are, for example, extensive updates to the Special topics in polymer chemistry" section, with an additional section on optically active polymers, expanded sections on ionic and co-ordination polymerisations, and copolymerisation, and additional examples of new environmental legislation are outlined wherever appropriate. 

Materials typically expand when heated. The expansion is characterized by the linear or volumetric thermal expansion coefficient. The three primary types of materials expand differently. Polymers expand more than metals, and metals expand more than ceramics. For many materials thermal expansion is related to the melting temperature of the material, also a relation between the thermal expansion coefficient of polymers and their elastic modulus is given. 

CAS 8063-94-3 9002-86-2 51248-43-2 93050-82-9 EINECS/ELINCS 208-750-2 Synonyms Atactic poly (vinyl chloride) Chloroethene homopolymer Chloroethylene polymer Ethene, chloro-, homopolymer Ethylene, chloro-, polymer Expanded polyvinyl chloride Poly (chloroethylene) Polyvinyl chloride latex Polyvinyl chloride resin PVC... 

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