Use as rheological additives

Special considerations fumed silica used as rheological additive addition of salts decreases solubility of resin in water... 

Rheological Additives. SAS serve as excellent rheological additives in a large number of liquid, pastelike, or thermoplastic systems and in solids. Between 0.1 and 2% of the additive is used for applications of this kind, whereas between 3 and 33% is used for the carrier applications discussed in the following section. Table VII lists the applications in which SAS are used as rheological additives. 

Acrylamide polymers are used as multipurpose additives in the oil-producing industry. Introduction of polymers into drilling fluids-drilling muds improves the rheological properties of the fluids in question, positively affects the size of suspended particles, and adds to filterability of well preparation to operation. Another important function is soil structure formation, which imparts additional strength to the well walls. A positive effect is also observed in secondary oil production, where acrylamide polymers additives improve the mobility of aqueous brines injections, which contribute to... 

Because minerals are an integral part of many enzymes, they play an important role in food processing, e.g., in alcoholic and lactic fermentation, meat aging, and dairy food production. Many compounds used as food additives or for rheological modification of some foods contain metallic cations in their structure. A number of these compounds function as antimicrobials, sequestrants, antioxidants, flavor enhancers, and buffering agents, and sometimes even as dietary supplements (Table 4.4). 

Xanthan Xanthomonas campestris It is used as rheology modifer and food additive... 

The use of rheology additives such as clays, plant exudates and natural polymers to formulate paints dates back to ancient times. These materials are used to thicken the fluid, suspend dispersions of additives in the fluid and improve the stability of the ensuing dispersion as a function of temperature and shear history. This paper classifies cellulosic rheology modifiers with respect to their influence on paint properties related to rheological profiles. 

Isocyanates by themselves cannot be used to bond plywood because of the characteristic balance of rheology and rate of hardening, which are characteristic of PMDl. However, recently, they have been used as minority additives (10-30%), copolymerized during panel hot-pressing with formaldehyde-based resins such as PF and even UF to yield very strong bondlines. These combinations have been used industrially to yield excellent bonding both in plywood and in particleboard. ... 

Mostly precipitated grades are used as rheological control additives in combination with medium (2-5 pm) or fine (1 pm) grades as extenders, the latter at levels of 40-200 phr. 

Star polymers are commonly used as rheology modifiers in applications such as coatings and oil additives, but can also be used in a variety of other ways. 

In addition to their use as absorbents, hormite clays are used as rheological agents. When dispersed in water, their needle-like particles deagglomerate in proportion to the amoimt of energy applied and form a random colloidal lattice. 

Other. A large variety of additives are used in paper-coatiag colors primarily to modify the physical properties of the colors (102). At high soHds concentrations in water, mineral pigment particles tend to associate and form viscous pastes. Dispersants (qv) are used to prevent this and to provide low viscosity slurries. Common dispersants include polyphosphates and sodium polyacrylate [9003-04-7]. Various water-soluble polymers are added to coatiag colors and act as water-retention agents and as rheology modifiers. 

Other Applications. PEO has also been used as an antistat additive (178,179), water-soluble packaging material of seeds and fertilizers (180), and rheology modifier in aqueous flexographic printing inks (qv) (181). 

The Cassia angustifolia GaM possesses the potential to become a new source of commercial gum due to its high content in the endosperm (about 50%) and its valuable rheological properties. It was suggested, in a similar way as for other GaMs, for usage as an additive in pharmaceutical formulations [188, 246]. Also the Ipomoea seed gum in its natural form, and after modification by grafting, has the potential to be used as a commercial gum [178]. 

Figures 20.13 and 20.14 describe the effect of dibutyltin dilaurate (DBTDL) on the tensile strength and tensile modulus for the 25/75 LCP/PEN blend fibers at draw ratios of 10 and 20 [13]. As expected, the addition of DBTDL slightly enhances the mechanical properties of the blends up to ca. 500 ppm of DBTDL. The optimum quantity of DBTDL seems to be about 500 ppm at a draw ratio of 20. However, the mechanical properties deteriorate when the concentration of catalyst exceeds this optimum level. From the previous relationships between the rheological properties and the mechanical properties, it can be discerned that the interfacial adhesion and the compatibility between the two phases, PEN and LCP, were enhanced. Hence, DBTDL can be used as a catalyst to achieve reactive compatibility in this blend system. This suggests the possibility of improving the interfacial adhesion between the immiscible polymer blends containing the LCP by reactive extrusion processing with a very short residence time.

The use of AMP as a rheology additive in paper coating is illustrated below. Table 1 gives formulation details. Figure 8 shows the colour viscosity at low shear rates and Figure 9 shows the colour viscoisty at high shear rates. The application was board basecoating at 62.5% solids. 

The synthesis of various multi-arm star polymers has long been of growing practical and theoretical interest to a variety of industries. Star polymers have shown to be useful as surfactants, lubricants, rheology modifiers, and viscosity modifiers. Actually, star polymers are considered as viscosity modifiers and oil additives (15). 

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