Fillers in plastics

The remaining tailings left over from the clay fractionation step is either flocculated with alum, high molecular weight polymers, or a weak (pH 3.0) solution of sulfuric acid, and stored in settling ponds as waste, or may be filtered and sold to the brick industry as a coating material. It also may be dried and sold as a filler in plastics and textured paint (qv). 

Inorganic fillers in plastics compositions are usually in a very finely divided form and, as such, are ideal for powder XRD study. A sample size of a few mg gives a good pattern in 1 or 2 h. Crystalline mineral fillers can usually be observed directly in the complete polymeric formulation, in concentrations exceeding about 1 %. Combined XRD/XRF studies are favoured [326]. A mineral filler is easy to identify in a compound in the absence of other fillers. 

Analysis of inorganic fillers in plastics and rubber materials is normally accomplished by ashing material in a muffle furnace at a temperature of 550°C. An IR spectrum of the resulting ash, sometimes as a paraffin oil mull is then obtained to identify the filler type. Examination of the ash by XRF and/or X-ray diffraction can also provide useful information to help identify complex systems. 

Layered clay silicates, generally from the intermediate-grained montmorillonite kaolin clay, are often used as filler in plastics and in the production of pottery and other ceramic items. These silicates consist of the silicate sheets held together mostly by the sodium cation with lesser amounts of other metal ions, such as iron, copper, nickel, etc. There are several approaches to open these silicate layers. 

Ihcin iiuvi been uj d iu ireut Ibe suituee ul glu.s. miil uliiei Mln-eons in.iie rials used as rein rcement or filler in plastics in order to promote adhesion of the polymers to the surface of the inorganic material (56). 

Terra alba or dead-burned, fine white gypsum is used as a paper filler, in plastics, and as an exlender far titanium dioxide. Pharmaceutically pure gypsum can be added to bread and other bakery products, finds use in beer production, and as a pharmaceutical-tablet diluent. In Japan, calcium sulfate is used in making tofu, a soyabean curd. 

Aluminum hydroxide is used in stomach antacids (including Maalox , Mylanta , and Delcid ), as a desiccant powder in antiperspirants and dentifrices in packaging materials as a chemical intermediate as a filler in plastics, rubber, cosmetics, and paper as a soft abrasive for brass and plastics as a glass additive to increase mechanical strength and resistance to thermal shock, weathering, and chemicals and in ceramics (HSDB 1995). Aluminum hydroxide is also used pharmaceutically to lower the plasma phosphorus levels of patients with renal failure (Budavari et al. 1989 Sax and Lewis 1987). 

Use Cement additive for oil-well casings, absorbent for oil spills (silicone-coated), to replace lime in scrubbing sulfur dioxide from flue gas, as a filler in plastics, source of germanium (England), proposed as catalyst for coal liquefaction, removal of heavy metals from industrial wastewaters, separation of oil-sand tailings. 

Use Fillers in plastics and rubber, paper coatings, antacids, anticaking agents, cements. 

Use Ceramics paint extender welding rod coatings rubber filler silica gels paper coating filler in plastics, cements, and wallboard mineral wool soil conditioner. 

MAJOR PRODUCT APPLICATIONS purification agent, asbestos replacement, filler in plastics and mbber, adhesives, blend compatibilizer... 

Numerous fibrous products are used as fillers in plastics materials. Fibers are generally divided into natural and man-made fibers. The natural fibers belong to three groups vegetable, animal, and mineral fibers. Natural mineral fibers were... 

Minerals, such as calcium carbonate, talc, silica, are quite common fillers in plastic industry. They, often at abont 6-15 cent/lb, replace a much more expensive plastic, increase stiffness of the filled product, and render the plastic more flame resistant. The world filler market for plastics is dominated by carbon black and calcium carbonate. Of abont 15 billion pounds of filler in America and Europe, about half the filler volume goes into elastomers, a third into thermoplastics, and the reminder into thermosets. About 15% of all manufactured plastics contain fillers. 

This chapter is not a comprehensive description of fillers in plastics and of the respective properties of the resulting materials. Books are written on this subject (see, for example. Ref. [1]). This chapter aims at a brief description of minerals which are either used as fillers in WPG or can be used readily, taking into account their cost and value-added properties. Besides, this chapter gives some examples of properties of WPGs after mineral fillers were added to the composition. 

There are three principal forms of CaC03 used as fillers in plastics— milled, precipitated, and coated. More than 90% of calcium carbonate is used as milled mineral. 

Starch utilization in plastic and rubber compositions began in the 60s and 70s, with oxidised starch in rubber and other polymers, such as urethane foams, poly(vinyl alcohol) and copolymers of poly(ethylene-co-acrylic acid) formulations, and as a filler in plasticized polyvinyl chloride (PVC) [37,39]. In another technique, gelatinized starch was mixed with PVC latex and the water was removed to give a PVC-starch composition, which was mixed with a PVC plasticizer such as dioctyl phthalate (DOP). 

Barium sulfate (BaS04) has an industrial relevance due to its whiteness, inertness, high specific gravity, and optical properties, such as opacity to UV rays and X-rays [164-167]. It is mainly used as a radio-contrast agent, filler in plastics, extender in paints, coatings and additive in pharmaceutical products, and in printing ink. Nowadays, interest on this material has been renewed with the development of methods to produce nanosized particles, supraparticles of a well-controlled number of nanoparticles and mesocrystals that mimic biomineralization processes. 

Talcum (talc, 14807-96-6) is a natural hydrous magnesium silicate that can be associated with deposits of crude asbestos. Industrial talc, used extensively as a filler in plastics, cosmetics, coatings, lubricating compositions, and polishes may contain or be strengthened with up to 2 particles per 100 of asbestos fibre. 

Table 5.9 Characteristic FTIR absorption bands for inorganic fillers in plastics ...

Use of regritid may have little effect on product performances (such as appearance, color, or strength). However, reduction in performance could occur with TPs such as the once-through shown in Figure 24. Granulated TSs can be used as additives or fillers in plastics they are not re-meltable. 

Fiber, straw A fibrous, cellulosic component of certain plants (wheat, rice, etc.). Its fibers are 1 to 1.5 mm long, similar to those of hardwoods. Straw can be used as filler in plastics. Its main use is preparing a pulp by the alkaline process to yield specialty papers of high quality. Use of straw for conventional papermaking in USA is of limited importance due to the abundance of pulpwood. 

These characteristics make cellulose fibers the most common choice for natural fillers in plastic materials. It was concluded that the presence of 25% w/w of cellulose fibers in a polypropylene matrix causes a significant increase in tensile modulus. Cellulose has a very long molecular chain, which is infusible and insoluble in all but the most aggressive solvents. Therefore, it is most often converted into derivatives to increase solubility, which further increases adhesion within the matrix (Kolybaba et al., 2001). 

Sanadi, A.R., Caulfield, D.F., Jacobson, R.E., Rowell, R.M. Renewable agricultural fibers as reinforcing fillers in plastics mechanical properties of Kenaf fiber polypropylene composites. Ind. Eng. Chem. Res. 34, 1889-1896 (1995)... 

Mineral fillers such as mica, kaolin, calcium carbonate, and talc are frequently incorporated in thermoplastics to reduce the costs and improve the properties of the polymers such as rigidity, durability, and hardness [30]. Talc is common filler in plastics as it serves as the most cost effective filler. Previous researchers have... 

Chem. Descrip. Surf.-modified calcium carbonate Uses Extender, filler in plastics and coatings Features Offers better physical, mech., and elec, insulation props., and improved props, under prolonged moisture saturation CARBOMgAX [Amspec]... 

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