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Chemical composition polymer embedding

Soluble supports for solution-phase combinatorial synthesis were extensively covered in Section 8.5. A recent survey of available soluble supports, with respect to their use in the soluble supported synthesis of various classes of chemicals (90), highlights the wide range of physicochemical properties (especially regarding solubility, tendency to crystallize, and solubilization power) that are embedded in different polymers and copolymers. The assessment of a sort of S AR for the composition of copol5miers versus their physicochemical properties would require the preparation of a large number of examples. Combinatorial approaches to soluble support libraries could be highly beneficial in this perspective. [Pg.600]

Novel hydroxyurethane modifiers (HUM) for cold-cured epoxy composite materials were synthesized. It is established that the compositions with HUM demonstrate a significant increase in the speed of the curing process, a nontrivial increase in abrasion resistance, and a marked improvement in strength properties. The HUM, which possesses a wide range of hydrogen bonds, is embedded in an epoxy polymer network without a direct chemical interaction. [Pg.263]

The presence of mineral reinforcements such as talc or mica, as foreign solid particles embedded into a polypropylene matrix, usually induces a nucleation effect. A signihcant increase in the crystalline content of the polymer is evidenced if compared with the neat polymer when processed at the same setup conditions that are necessary to ensure a good accommodation of the solid particles into the amorphous phase of the polymer in order to obtain a material with a good mechanical performance (27). The comparison between PP/mica and PP/talc composites in terms of their mechanical behavior under dynamic conditions in the solid state agrees with the morphological features derived from their chemical structures of both minerals (28). [Pg.389]

Kunz and Kirschning developed a chemically functionalized monolithic material which is based on a glass/polymer composite [28,29] (refer to Sect. 3.1). This material is available in different shapes including rods, disks, and Raschig rings. The polymeric phase of this composite was chemically functionalized (e.g., substitution of the benzylic chlorine by trimethylamine or sulfonation). Rod-shaped objects were first embedded in a solvent-resistant and shrinkable PTFE tube. This was followed by encapsulation with a pressure-resistant fiber-reinforced epoxy resin housing with two standard HPLC fittings, which created... [Pg.222]

Metal particles may be embedded in a polymer matrix in a variety of ways. These are chemical synthesis in an organic solvent [2], vacuum deposition on viscous-flow polymers [3], plasma polymerization combined with metal evaporation [4], and so on. However, they all suffer from disadvantages, such as a low filling factor or a great spread in size and shape of particles synthesized, which offsets the good optical properties of composites. [Pg.242]

Recently, ultrafine metai particles have attracted much interest because of their unique properties which differ from those of buiK metals, e.g., quantum size effect, such as low melting point, plasmon resonance absorption and so an It is well known that ultrafine metal particles are quite active because of their large surface area and that they are liable to aggregate and grow in size. Thus, it is necessary to maintain them in stable form in a matrix for size control and tor narrow size distribution. Ultrafine metal partides-polymer composites, which are prepared by embedding ntetal particles in a polymer, can be used as electrical, magnetic, optical or chemically useful materials. The techniques to prepare ultrafine metal partides-polymer composites have been explored end reported by many researchers. Many of these involve co-evaporation or co-sputtering of a metal and polymer . In the case of thesb methods, however, metal-polymer composites have to be prepared at a rate below ca. 10 nm/min so that ultrafine metal particles will not... [Pg.95]


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See also in sourсe #XX -- [ Pg.2 ]




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