Plastics additives fillers

In addition to the broad categories of TPs and TSs, TPs can be further classified in terms of their structure, as either crystalline, amorphous, or liquid crystalline. Other classes (terms) include elastomers, copolymers, compounds, commodity resins, engineering plastics, or neat plastics. Additives, fillers, and reinforcements are other classifications that relate directly to plastics properties and performance. 

Plastics Additives, fillers Short-term Long-term... 

Commercially produced elastic materials have a number of additives. Fillers, such as carbon black, increase tensile strength and elasticity by forming weak cross links between chains. This also makes a material stilfer and increases toughness. Plasticizers may be added to soften the material. Determining the effect of additives is generally done experimentally, although mesoscale methods have the potential to simulate this. 

Plasticizers. Addition of plasticizers (qv) to polyether elastomers alters physical properties, improves processing, and can improve low temperature flexibiUty. Plasticizers also reduce vulcanizate costs by allowing the use of higher levels of less expensive fillers. 

Many different additives, fillers, and/or reinforcements are used in plastic materials. The weight of the compounds change according to the amount included. Figure 5-3 provides a guide to determining their specific gravities. 

The term s plastic, polymer, resin, elastomer, and reinforced plastic (RP) are some-what synonymous. However, polymer and resin usually denote the basic material. Whereas plastic pertains to polymers or resins containing additives, fillers, and/or reinforcements. Recognize that practically all materials worldwide contain some type of additive or ingredient. An elastomer is a rubberlike material (natural or synthetic). Reinforced plastics (also called composites although to be more accurate called plastic composites) are plastics with reinforcing additives, such as fibers and whiskers, added principally to increase the product s mechanical properties. 

Identifies a plastics with Nothing Else Added To. It is a true virgin polymer since it does not contain additives, fillers, etc. These are very rarely used. 

Even though equipment operations have understandable but controllable variables that influence processing, the usual most uncontrollable variable in the process can be the plastic material. The degree of properly compounding or blending by the plastic manufacturer, converter, or in-house by the fabricator is important. Most additives, fillers, and/or reinforcements when not properly compounded will significantly influence processability and fabricated product performances. 

For applications having only moderate thermal requirements, thermal decomposition may not be an important consideration. However, if the product requires dimensional stability at high temperatures, it is possible that its service temperature or processing temperature may approach its temperature of decomposition (Tj) (Table 7-12). A plastic s decomposition temperature is largely determined by the elements and their bonding within the molecular structures as well as the characteristics of additives, fillers, and reinforcements that may be in them. 

Powder coating is a solventless coating system that is not dependent upon a sacrificial medium such as a solvent, but is based on the performance constituents of solid TP or TS plastics. It can be a homogeneous blend of the plastic with fillers and additives in the form of a dry, fine-particle-size compound similar to flour. The three basic methods are the fluidized bed, electrostatic spray, and electrostatic fluidized bed processes (9). 

The property sets of raw PVCs as-polymerized are generally unsuitable for the range of intended applications. It is essential to upgrade and customize the raw polymers by compounding to satisfy the requirements of customers and applications. Numerous additives, fillers, plasticizers, stabilizers etc. are used, allowing the manufacture of a variety of parts and goods from a very rigid to a very soft character. 

PVC is regarded as perhaps the most versatile thermoplastic resin, due to its ability to accept an extremely wide variety of additives Plasticizers, stabilizers, fillers, processing aids, impact modifiers, lubricants, foaming agents, biocides, pigments, reinforcements. .. 

The Tg value is reduced by the addition of moderate amounts of plasticizers (additive which reduces intermolecular forces) and is sometimes even increased by the addition of small amounts of plasticizers (antiplasticization) and optimum amounts of fillers (usually a relatively inert material used as the discontinuous phase of a composite) and reinforcements (materials such as fibrous additives which give increased strength to a polymer). 

Schlumpf H P (1990) Fillers and reinforcements, In Plastics additives handbook, Gachter R and Muller H (Eds), Hanser Publishers Munich, pp 525-591. 

There are different types of plastics that are usually identified by their composition and/or performance. As an example there are virgin plastics. They are plastic materials that have not been subjected to any fabricating process. NEAT polymers identify plastics with Nothing Else Added To. They are true virgin polymers since they do not contain additives, fillers, etc. They are very rarely used. Plastic materials to be processed are in the form of pellets, granules, flakes, powders, flocks, liquids, etc. Of the 35,000 types available worldwide there are about 200 basic types or families that are commercially recognized with less than 20 that are popularly used. Examples of these plastics are shown in Table 1.1. 

The materials being reviewed in this book, as in the industry, are identified by different terms such as polymer, plastic, resin, elastomer, reinforced plastic (RP), and composite unreinforced or reinforced plastic. They are somewhat synonymous. Polymers, the basic ingredients in plastics, can be defined as high molecular weight organic chemical compounds, synthetic or natural substances consisting of molecules. Practically all of these polymers are compounded with other products (additives, fillers, reinforcements, etc.) to provide many different properties and/or processing capabilities. Thus plastics is the correct technical term to use except in very few applications where only the polymer is used to fabricate products. 

Converting polymers to almost 35,000 plastics includes mechanical mixing/blending one or more polymers with additives, fillers, and/or reinforcement. They do not normally depend on chemical bonds, but do often require special compatibilizers. Mechanical compounding is extensively used (Chapter 5). 

In the past engineering TPs have replaced metal in numerous products in many industries by providing improvements in thermal properties.146 The ability to prepare and compound material properties through the choice of plastics with additives, fillers and reinforcements, has allowed the development of the flexibility inherent in TPs to meet the performance requirements required in these different applications. 

The twin-screw extruder may have parallel or conical screws, and these screws may rotate in the same direction (co-rotating) or in opposite directions (contra-rotating). Extruders with more than two screws are known as the multiple-screw extruder. These extruders are normally used when mixing and homogenization of the melt is very important, in particular where additives, fillers, and/or reinforcements are to be included in the plastic. 

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