Macromolecular dispersants

At a sliding velocity of o.l m/s patch-like transfer was observed that roughened the metallic surfaces. The size of the polymer patches transferred onto metal increased with load which intensified macromolecular dispersion ( Eigs. 1 to 3,... 

Macromolecular dispersion in HDPE with patch—like transfer is defined by polymer—metal and polymer—polymer adhesive interactions. The major contribution to macromolecular dispersion is from the alternating areas of polymer—polymer and metal-polymer contacts. Macroradicals generated within polymer—polymer contact may recombine on the metallic surface to form chemisorption and coordination complexes with an oxide film. Under the dynamic contact this process may increase the effect of mechanical actions on the macromolecular dispersion of polyolefine. 

At a sliding velocity of 0.5 m/s under the environmental conditions film—like transfer took place which caused a decrease in macromolecular dispersion as compared to the patch-like mode of transfer ( Table I ). At a load of 0.5 MPa M and Mj dropped by 48 % and 37 % for patch-like transfer at a sliding velocity of 0.1 m/s, and by 35 % and 23 % for film-like transfer at a sliding velocity of 0.5 m/s. 

The data given in the paper on HDPE macromolecular dispersion based on rubbing conditions allow a conclusion that the degree of dispersion depends mainly on load. Effect of velocity on this process is indirect and related to the transfer mode or to the ratio of the metal-polymer and polymer-polymer contact areas. If the metal—polymer contact area is predominant this leads to intensification of macromolecular dispersion. 

Mechano—chemical processes that are essential for HDPE macromolecular dispersion were defined by analyzing MWD of the transfer fragments of polyolefine—based composites doped with active additives (5 wt.%), such as antioxidant (Neozone D), aromatic compound (anthracene) and metal seilt (zinc stearate). Effect of the active additives on molecular features and certain friction characteristics of HDPE (load 0.5 MPa sliding velocity = 0.25 m/s) is shown in Table II. 

The substance should provide intensive macromolecular dispersion in the transfer and wear products. 

The origin of the metal influences undoubtedly the HDPE macromolecular dispersion. At a sliding velocity of 0.25 m/s and load of 0.5 MPa M- of the transferred products decreased as compared to the original HDPE in the following way in contact with steel - by 10% with copper - by 12% ... 

By combining these glycol ethers given in Table 3.2 with a pol5tmer and a macromolecular dispersant, the bleeding can be reduced to enhance the printing quality (3). 

Water-soluble EMA resins and derivatives of these materials function very well as dispersants (Table A.3). For example, the amide-salt derivative exhibits excellent dispersant properties for pigments in waterborne synthetic latice systems. Dispersants for the coatings, rubber, leather, cosmetic, ceramics, photographic film, and agricultural field have been claimed for EMA resins. The linear derivatives are especially useful as dispersants and stabilizers for emulsion bead polymerizations. For example, EMA-type dispersants (emulsifiers) are very useful for PVC production. The resins also function well as macromolecular dispersants for the suspension copolymerization of a-olefins and aromatic vinyl compounds with MA. ... 

Macromolecular stmcture and supermolecular organization also affect dye affinity. Drawn (oriented) nylon-6 has more of a random open stmcture than nylon-6,6 (172). Nylon-6, therefore, dyes more rapidly than nylon-6,6, but is also more susceptible to color crocking, especially with disperse dyes. 

Natural macromolecular materials, which form multimolecular films around the disperse droplets of O/W emulsions. They are frequently called auxiliary emulsifying agents and have the desirable effect of increasing the viscosity of the dispersion medium. However, they often suffer from the disadvantages of being subject to hydrolysis and sensitive to variations in pH. 

Rate equation analyses for classical size exclusion chromatography have been based on treating the porous matrix as a homogeneous, spherical medium within which radial diffusion of the macromolecular solute takes place (e.g. (28,30,31)) or If mobile phase lateral dispersion Is considered Important, a two dimensional channel has been used as a model for the bed (32). In either case, however, no treatment of the effects to be expected with charged Brownian solute particles has been presented. As a... 

The fifth chapter is dedicated to macromolecular iodinated contrast agents with low dispersity. They can be utilized as blood-pool agents. The synthesis, analysis and pharmacokinetics of this class of compounds is summarized and their diagnostic impact is evaluated. 

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