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It is important to recognize that these correlations only apply to a specific polymer and, as discussed above, will be sensitive to changes in the polymer crystallinity, the inclusion of filler, and the exact chemical composition. The sensitivity of solubility in polydimethylsiloxane to the filler content has been noted (14 15) and the correlation in Table III for PDMS applies ony to the unfilled fluid. The crystallinity of many polymers depends on their molecular weight, and may change if the polymer is subject to biodegradation. The solubility parameter, i.e. the polarity, of polyurethanes, is sensitive to the nature and ratio of the ether (or ester) and urethane segments. [Pg.68]

The physical properties (e.g., color, density, solids or filler content, electrical properties, etc.) and working properties (storage life, pot life, viscosity, etc.) often need to be considered and subjected to screening testing too. [Pg.95]

The optimum solids level of cements to be applied by various methods is, of course, subject to broad variation depending on the solvent selected (i.e., the viscosity which results), filler content, etc. In general, butyl rubber and polyisobutylene cements for application by spraying contain 5-10% solids, for dipping 10-30%, for spreading 25-55 %, and for application by finger or spatula, 50-70%. [Pg.192]

Figure 11.16 Left MD simulations of filled silicone systems subject to tensile strain (here lamba=2.0) as a function of filler content, showing that cavitation occurs to a larger extent in unfilled networks and that in filled systems, cavitation seems to occur preferentially near the filler surface. The MD simulations also allowed the identification of chains that are preferentially ordered along the strain axis (monomers colored green). Right increased presence of cavitation detected by Carr-PurceU-Meibloom-GiU (CPMG) spin echo NMR experiments on filled networks subject to ionizing radiation while under tensile strain. Figure 11.16 Left MD simulations of filled silicone systems subject to tensile strain (here lamba=2.0) as a function of filler content, showing that cavitation occurs to a larger extent in unfilled networks and that in filled systems, cavitation seems to occur preferentially near the filler surface. The MD simulations also allowed the identification of chains that are preferentially ordered along the strain axis (monomers colored green). Right increased presence of cavitation detected by Carr-PurceU-Meibloom-GiU (CPMG) spin echo NMR experiments on filled networks subject to ionizing radiation while under tensile strain.
The aluminum industry consumes about 0.45 lb. of anode carbon for each pound of aluminum produced. The ideal carbon should have a moderately-isotropic structure with minimum oxidant-accessible surface of low, uniform reactivity, and a maximum ash content, excluding bath salts, of a few tenths of one percent. Industrial anode carbon is a baked composite usually made of calcined petroleum coke filler with a binder of coal-tar pitch coke. While there is no shortage of calcined petroleum coke, the quality is not very good and likely to become worse. Also, coke binders are subject to variability in both quality and supply. [Pg.242]

Minerals often contain admixtures (such as free metals) which catalyze thermo-and/or photooxidation of the filled plastic. This subject will be considered in more detail in Chapter 15. Here we give just two examples of fading of CaCOs-fllled HDPE and polypropylene, with 76 and 80% w/w of the filler, respectively. The matrix had the melt flow index equal to 1 g/10 min (HDPE) and 8 g/10 min (polypropylene). Ashing of the both filled plastics at 525°C gave ash content of... [Pg.132]

Fillers are used in adhesives to improve physical properties, to control rheology, and to lower cost. The most common polyurethane fillers are calcium carbonate, talc, silica, clay, and carbon black. A more rigorous treatment of this subject can be found in Katz and Milewski [47]. Fumed silicas and carbon blacks are used primarily as thixotropes in application areas that require a nonsagging bead. Calcium carbonates, clays, and talcs are used to improve the economics of an adhesive formulation. A major concern using fillers with urethane prepolymers is the moisture content associated with the fillers. Fillers typically must be dried prior to use with urethane prepolymers or isocyanates. Hygroscopic fillers should be avoided, as moisture introduced by the filler can lead to poor shelf stability of the finished product. [Pg.704]

The polycarbonate exhibits a typical Newtonian flow behaviour at the low shear rates investigated, while it shows the tendency to continuosly shear thin, if subjected to high shear rates. The same flow behaviour is exhibited by the blends with the lower content of the liquid-crystalline filler. At higher content of liquid-crystalline filler, the rheology of the blend is strongly affected by the presence of the second phase, whose viscosity continuously shear thins over the shear rates investigated. [Pg.398]

Incoming raw materials, specifically the matrix constituents and the fibre rovings and mats, should be inspected. Basic inspection includes checking the delivery notes and the labels of containers when the materials arrive. Visual inspection of raw materials is also recommended resins can be inspected for colour and the presence of contamination and gel particles (Evans, 2000) reinforcements can be checked for the presence of knots in the rovings, while simple mass measurements can be made for mats or fabrics. Some pultrusion companies have quality control and/or research and development laboratories where material characterisation tests can be performed (most often such control is executed by raw material suppliers). Fibre reinforcements can be subjected to tensile tests. The moisture content of the constituents (particularly the reinforcements and the fillers) can also be determined. The quality of incoming resins can be tested by means of thermal analysers (resin reactivity) and viscometers (resin viscosity and thixotropic index) (Owens Coming, 2003). [Pg.221]

The presence of natural fillers causes a slightly increased water resistance and could improve the apphcation property of these composite films. This behavior could be due to the presence of hydrogen bonding interactions between starch polymer matrix and crystaUine part of wood and fir tree needles fillers (which comprise cellulose in their chemical composition). The hydrogen bonds network occurred within the composite films tends to stabilize the starch polymer matrix when it is subjected to high moisture content environment. [Pg.484]


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