Oxide melts surface tension

Carboxylic acid melting peak Oxidation shoulder Surface tension Specific interaction term... 

Physicochemical properties Melting point Boiling point Relative density Vapour pressure Surface tension Water solubility Fat solubility Partition coefficient Flash point Flammability Explosivity Autoflammability Oxidizing properties... 

Although more expensive than melt fiberization, the sol processes offer advantages in fiber chemistry selection. In melt fiberization, viscosity and surface tension are gready influenced by additions of small quantities metallic oxides. In the sol process, where viscosity can be controlled independently, any number of metal salts may be added without adverse effects. These salts can serve as grain growth inhibitors, sintering aids, phase stabilizers, or catalysts. 

Surface Tension of Liquid Metals and Oxide Melts. S. 243 in (267). 

Surface tension of binary alkali-silica melts at 1300 °C is shown in Fig. 44, The effect of other oxides on the surface tension of a sodium oxide-silica melt is demonstrated in Fig. 45. 

FIG. 45. Changes in surface tension of a melt containing 80 wt. % S1O2—20 wt.% Na20 due to replacing SiOj with other oxides (from Scholze, 1965). 

From the viscosity, as well as the phase equilibrium, surface tension, and density measurements it is evident that the system KF-K2M0O4-B2O3 is very complex. Beside the chemical reactions, the polymerization tendency of the melts, especially in the region of higher contents of boron oxide, makes this system difficult to study. 

The most widely used thermoplastic polymer is the ethylene—vinyl acetate copolymer, which is obtainable in a wide range of molecular weights as well as in a variety of compositions. Often flexibilizers or plasticizers are added in order to improve both the mechanical shock resistance and the thermal properties of the adhesive. Polybutenes, phthalates, and tricresyl phosphate have been used as plasticizers. Tackifying agents can also be added. Because hot-melt adhesives are frequendy ethylene-based, they are subject to oxidation if, as in a typical situation, the adhesive sits in an applicator for long periods before use. Thus, antioxidants such as hindered phenols are often used, as are fillers. Fillers are added to opacify or to modify the adhesive s flow characteristics, as well as to reduce cost. Wax is also a very important component. Wax alters surface characteristics by decreasing both the liquid adhesive s surface tension and its viscosity in the melt. Upon solidification, however, the wax acts to increase the strength of the adhesive. Both paraffin and microcrystalline wax are used (see Waxes). 

A study of the contact and adhesion of surfaces under compressive stress in ambient air was carried out by 0. L. Anderson [21]. A small specimen of gold was fashioned by melting the end of a fine wire the ball thus formed was shaped into a sphere by the surface tension forces. The ball was cooled and subsequently manipulated in air therefore its surface carried the ordinary adsorbed films of atmospheric gases and water vapor. Since gold does not form an oxide by direct reaction with atmospheric oxygen, the film was not of the chemisorbed type and hence was easily removable. 

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