Kaolin viscosity

Properties. The properties of kaolin that make it useful in the paper industry are brightness, viscosity, and particle si2e and shape. 

Testing. The Technical Association of the Pulp and Paper Industry (TAPPl) gives test methods that are widely used by kaolin suppHers to the paper iadustry. These iaclude tests for viscosity, viscosity stabiUty, brightness, pH, particle size distribution, moisture content, and screen residue (12). 

It has been found that, for a fixed mineral filler content, the viscosity of PMF-based composites increases when the coat is made of polyethylene [164, 209, 293], poly(vinyl chloride) [316] and polypropylene [326, 327], The picture was different, however, for composites based on the ethylene/vinyl acetate copolymer to which kaolin with grafted poly (vinyl acetate) was added [336]. Addition of PMF with a minimum quantity of grafted polymer results in a sharp drop of flowability (rise of viscosity), in comparison to addition of unmodified filler but with a further increase of the quantity of grafted polymer the flow gradually increases and, depending on the kaolin content and quantity of grafted polymer, may even become higher than in specimens with unmodified filler, for equal concentrations. 

An aqueous base is the least expensive vehicle and poses no toxicity problems. A solution of the drug in water or water and cosolvent is made. Glycerin, glycols, natural and synthetic gums, and/or polymers are used to increase viscosity, cohesiveness, and plasticity. To overcome syneresis, or water separation in the gel, a common problem with aqueous bases, one can use absorbing materials such as microcrystalline cellulose, kaolin, colloidal silicon dioxide, starch, etc. 

Adsorption isotherms for AMP-QS onto kaolin, titania and calcium carbonate are shown in Figure 4. Viscosity profiles obtained when AMP is used to disperse titania and kaolin are shown in Figures 5-7. 

Figure 6 Viscosity profile for kaolin dispersed with AMP and polyacrylate...

Figure 7 Hercules viscosities for AMP and polyacrylate dispersed kaolin...

Figure 3 Typical viscosity vs. dispersant dose for Na polyacrylate on coating grade kaolin 0.6 pm - 68% solids)...

Measures taken to minimise the amount of unadsorbed polymer in solution have been shown to improve the viscosity performance of both kaolin and calcium carbonate slurries. These include adjustment of the pH or initial neutralisation of the polymer to increase its affinity to the surface and fractionation of the polymer to reduce the width of its molecular weight distribution. 

Other mineral additives have been used for many years as functional extenders and fillers in adhesives and sealants. These include kaolin (hydrated aluminum silicate), bentonite (hectorite clay), talc (magnesium silicate), and attapulgite (hydrated magnesium aluminum silicate) additives.1213 Kaolin and talc are considered to be viscosity thickeners whereas attapulgite is more of a conventional thixotrope. They are considered to be very cost-effective rheological additives. 

Kaolin has a use in plastisol formulations giving good rheological control. Calcium carbonate is also used in this area. An alternative to calcium carbonate, phyllite, has been evaluated. This material, which contains quartz, muscovite and kaolinite, was characterised on the basis of paste viscosity, gelation and fusion behaviour, and mechanical properties (70). 

Chemical reaction depends on the presence of reactive substrates and on the probability of their encounters. Thus, the possibilities of reactions can be numerous. The literature describes reactions of OH groups on the surface of kaolin with isocyanates, vulcanization of nitrile rubber by ZnO, reactions of carboxyl groups on the filler surface with amines and epoxy groups, reactions of carboxyl groups with diols," and many others.The presence of a reactant on the surface of a material particle increases the probability of chemical reaction. Other factors include statistical probabilities, surface barriers which affect contact, dilution factors, molecular mobility, and viscosity changes in the system. These are discussed in other sections of this book. 

This property can be beneficial for hydrophobic plastics, such as polyolefins, as hydrophobic fillers can show a good interaction with the matrix. Also, hydrophobic fillers can very significantly influence the viscosity of the matrix, hence, its rheology and flowability. Fillers typically absorb oil in much higher quantities compared to water. Calcium carbonate absorbs 13-21% of oil, aluminum trihydrate absorbs 12-41% of oil, titanium dioxide 10-45%, wollastonite 19-47%, kaolin 27-48%, talc 22-57%, mica 65-72%, and wood flour 55-60%. Biodac absorbs 150% of oil by weight. 

Ability to absorb oil, 101, 124, 129 Aluminum trihydrate, 129 Biodac , 101, 129 Calcium carbonate, 129 Hot melt viscosity, effect on, 129 Kaolin, 129 Mica, 129... 

Surfactant adsorption on the reservoir surface is another important factor to be considered when using foams in EOR processes is discussed in [258]. Adsorption experiments with surfactants of different structures were performed on cores of a number of materials (quartz, sandstones, kaolin, calcite and others), both clean and modified (impregnated) with hydrocarbons of various structure ( light oil, high-viscosity oil, asphaltenes). Minimum adsorption, as well as maximum oil recovery based was observed when using amphoteric surfactants as well as surfactant mixtures, e.g. diphenyl ether disulfonate - a-olefin sulfonate (DPES-AOS). 

Fig. 5. Viscosity curve of PP-kaolin composites using a Melt Flow Indexer (MFI) at 210°C...

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