Fillers moisture content

Moisture. The presence of water in a filler is not usually beneficial. Most fillers added to adhesives have a moisture content lower than 1 wt%. Only precipitated silicas and sepiolite contain about 5-10 wt% moisture. For some applications, fillers must be completely dried to exhibit adequate performance. Moisture absorbed on the surface of fillers impacts the rate and extent of curing of rubber base adhesives. 

Separation Efficiency. Similarly to other unit operations in chemical engineering, filtration is never complete. Some solids may leave in the liquid stream, and Some liquid will be entrained with the separated solids. As emphasis on the separation efficiency of solids or liquid varies with application, the two are usually measured separately. Separation of solids is measured by total or fractional recovery, i.e., how much of the incoming solids is collected by the filter. Separation of liquid usually is measured in how much of it has been left in the filtration cake for a surface filter, i.e., moisture content, or in the concentrated slurry for a filler-thickenef. i.e., solids concentration. 

Despite the disadvantages, the advantages of high throughputs and low moisture contents m the filtration cakes have justified the vigorous development of continuous pressure fillers. 

The pulp recovered during screening may be transferred to a pulp-wash operation to yield further soluble solids by counter-current extraction with water. The washed pulp may be held for further processing or included with the bulk of ejected peel material from the extractors. This is milled, treated with lime (calcium hydroxide or calcium oxide) to break down pectin and reduce water retention, pressed, dried to c.10-12% moisture content and finally converted to pellets. Being high in carbohydrates these are used as filler in livestock feed blends. 

Good acceptance of damp fillers such as high-moisture-content sands, cements, and oxides... 

The cotton and rayon used as fillers in solid oral dosage form containers may not meet pharmacopeial standards, but through appropriate tests and acceptance criteria for identification and moisture content, their adequacy should be shown. For example, rayon has been found to be a potential source of dissolution problems for gelatin capsules and gelatin-coated tablets. 

Anhydrous lactose is widely used in direct compression tableting applications and as a tablet and capsule filler and binder. Anhydrous lactose can be used with moisture-sensitive drugs due to its low moisture content. 

Except for the CMUs which were produced in an industrial block plant, the batches were completed following the same procedure. Before starting a typical concrete batch, the water, sand and pea gravel were adjusted for moisture content. The two aggregates and the plastic filler were introduced into the mixer and mixed for approximately 30 seconds. The cement and two-thirds of the total water were added and the drum was rotated for 2 minutes more. The rest of the water was added within the next 30 seconds. After two minutes the drum was stopped, and the slump test was performed. The drum was then scraped to loosen any material not previously mixed. It was restarted and rotated... 

Intermediate moisture content foods (IMFs) such as pet food and continental sausages rely on fats and water-binding humectants such as glycerol to lower water activity. Fat, which is essentially hydrophobic, does not bind water, but acts as a filler for IMFs to increase the volume of the product. 

Intermediate bulk containers vary in size and construction but usually contain about 1000 kg of product. These containers are made from coated or uncoated cloth and are equipped with a lifting collar at the top and a discharge valve at the bottom. Although in a chemical plant environment fillers packed in paper sacks is a common sight only 10% of fillers are transported in packages, the remainder is shipped in bulk. Only industries which are particularly strict about moisture content will prefer material packed in sacks. From the point of view of material handling and exposure to dust, fillers packed in sacks are least safe because they cause the highest emission of dust in the work environment. 

It is usually important to know how much moisture is present in a filler and whether or not the filler is hygroscopic. Table 5.12 gives an overview of typical moisture concentration in some fillers (the fillers are qualified to a particular group based on their lower limiting value of the moisture concentration range). The information in the table is based on data for a large number of grades which vary in moisture content. 

Methods of filler pretreatment moisture content of composite should be below 0.02% to avoid hydrolytic changes as well as blistering... 

Typically, recycled paper sludge is made up of approximately 50% cellulose, 10 % hemicellulose and 40 % other materials, and has a moisture content of about 60%. For example, with a dry ton of recovered paper for repulping, there is about 0.15 to 0.2 ton of dry short fibers generated. The wet weight of RPS will be up to 0.5 ton including water, short fiber and other solids known as fillers. Because of its high fiber content, RPS is the type of material that can be effectively utilized and converted into ethanol. The ideal method of producing ethanol from RPS is to use the simultaneous saccharification and fermentation (SSF) process. 

An Instron tensile machine can be used to measure stress and strain in the automotive lab. However, incoming inspection at a supplier is generally where this type of analysis takes place. More often, an automotive chemist at an OEM will be required to analyze a sample for failure analysis of that particular part. A thermogravimetric analyzer (TGA) will measure the change in mass of an elastomer in an inert (nitrogen) atmosphere as the temperature is waived. These instruments are very precise and will give information such as degradation temperature, filler content solvent residue, and absorbed moisture content. 

Surface modifiers are used for a number of reasons, and these include reduction of dustiness and moisture content, improved processing, and enhanced composite properties. Table 11.1 shows that filling polypropylene with uncoated magnesium hydroxide results in a significant decrease in impact and flexural strength. However, surface treatment of the filler can counteract these effects to some degree. 

Low moisture content of fillers are typically observed in calcium carbonate and wollastonite (0.01-0.5%), talc and aluminum trihydrate, mica (0.1-0.6%). Medium moisture content can be observed in titanium hydroxide (to 1.5%), clay (to 3%), kaolin (1-2%), and Biodac (2-3%). High moisture content is often seen in cellulose fiber (5-10%), wood flour (to 12%), and fly ash (to 20%). Biodac absorbs 120% of water under direct contact with an excess of water. 

Besides the principal silicon oxide, common silica fillers include other oxides as minor inclusions or traces, such as AI2O3, Fc203, Ti02, CaO, MgO, Na2S04, and trace elements. Specific gravity (density) of silica is 1.9-2.2 g/cm, moisture content is typically from 0.1 to 7%, and can go up as high as 20%. Particle sizes of commercial silica grades, which are typically white powder, are from less than 1 to 40 pm, oil absorption between 20 and 330 g/100 g, specific surface area from 1 to 800 mVg. 

When WPC materials are manufactured with the same formulation but at a different speed, using vented or nonvented extruders, different moisture content of cellulosic filler, and so on, the resulting profiles often have different density (specific gravity). As a rule, the higher the specific gravity, the higher the flexural strength (Table 7.23). 

The dimensions of a polymeric component are temperature, time and moisture content dependent. The extent of these dimensional instability effects, especially those related to temperature and moisture content is important if the physical properties of different engineering polymers are compared. The expansion due to moisture absorption of polyketone and that of a alternative system Minion 13T1 (Nylon 6.6 with 33 %wt. mineral filler) were measured in order to obtain such a comparison. 

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