Surface-treated extenders

Inks. Refined kaolin is a common ingredient in a large variety of printing inks (qv). In addition to extending the more expensive polymers present, ka olin also contributes to improved color strength, limits the penetration of the ink into the paper, controls rheology, and improves adhesion. Kaolin for this appHcation must usually be as white as possible and free from oversize particles. Surface treated clays are used to improve compatibiHty with oil-based ink. Clays can also be an ingredient in the newer water-based or uv-cured inks. 

It is clear that the acoustic emission technique is capable of providing valuable information on the in situ strength of surface treated fibers, especially at very small gauge lengths approaching the critical aspect ratio of the fiber in the composite. The AE method should also be useful in extending the SFC test to opaque matrix resins, through which fiber fracture cannot be observed by the optical microscope. 

The hybrid micrometric/nanometric filled polymer has significantly improved properties, both modulus and toughness, if we compare it for instance to surface treated natural CaC03 (95T) as a filler. The process zone size, developed ahead of the main propagating crack, is extended up to 2-4 mm. 

This problem is circumvented by a construct devised by J. W. Gibbs. Imagine that the gas-phase properties extend unchanged up to the solid surface. Differences between the actual and the unchangedproperties can then be attributed to a mathematical surface, treated as a two-dimensional phase with its own thenuodynamic properties. This provides not only a precisely defined surface phase to accountfor the singularitiesof the interfacial region, but it also extracts them from the three-dimensional gas phase so that it too may be treated precisely. The solid, despite the influence of its force field, is presumed inert and not otherwise to participate in the gas/adsorbate equilibrium. Thus for purposes of thenuodynamic analysis the adsorbate is treated as a two-dimensionalphase, inherently an open system because it is in equilibrium with the gas phase. 

The serious drop in strength of epoxy bonded carbon steel structural joints exposed to humid environments for extended periods of time is greatly reduced by surface treating the bond surfaces with polyfunctional mercaptoester coupling agents. 

Economic Aspects. The calcium carbonates (calcites, chalks, limestone powders, dolomites, precipitated calcium carbonates, and surface-treated carbonates) account for 80-90 % of the extenders used in Western Europe. In the Federal Republic of Germany calcium carbonates are more predominant than in the remainder of Western Europe (ca. 90%) calcites with a high degree of whiteness and a mean particle size of 2-5 pm are most widely used. Next follow talc, kaolins (with calcined kaolins), silica, barytes, and mica. 

Polypropylene (PP500P, SABIC) has melt flow rate of 3.1 (2.16 kg at 230 °C) and density of 905 kg/m3 was used as matrix resin. Nano-sized synthetic ultrafine surface treated precipitated calcium carbonate (Socal 312, Solvay, France) with mean particle diameter of 70 nm used as filler phase. PP-g-MAH compatibiliser (Priex 20097, Solvay, France) with a maleic anhydride content of 0.05 wt % and MFI of 15 (2.16 kg at 230 °C) was employed to promote the interfacial interaction between nano-CaC03 and PP, and to extend the dispersion of nanoparticles in polymer matrix. Compounds used as processing materials are listed in the table 1. 

An alternative way of deriving the BET equation is to express the problem in statistical-mechanical rather than kinetic terms. Adsorption is explicitly assumed to be localized the surface is regarded as an array of identical adsorption sites, and each of these sites is assumed to form the base of a stack of sites extending out from the surface each stack is treated as a separate system, i.e. the occupancy of any site is independent of the occupancy of sites in neighbouring stacks—a condition which corresponds to the neglect of lateral interactions in the BET model. The further postulate that in any stack the site in the ith layer can be occupied only if all the underlying sites are already occupied, corresponds to the BET picture in which condensation of molecules to form the ith layer can only take place on to molecules which are present in the (i — l)th layer. 

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