Processing of Thermoplasts, Thermosets, and Elastomers

The choice of a processing technique is influenced technically by the rheological properties of the material and the form or shape of the desired product. Important economic features such as the cost of the processing machines and the number of pieces which can be produced per unit time also play a considerable role. 

The methods can also be classified, as in Table 12-3, according to the type of form or shape which is produced. 

Classification according to the pressure used, the continuity of the process (discontinuous, semicontinuous, continuous, or automated), or the 

Viscous Molding, compression molding, direct injection molding, coating 

Elastoviscous Injection molding, extruding, calendering, milling, internal mixing (kneading) 

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Although thermoplastics, thermosets and elastomers can be used as matrix of polymer composites, thermosets are more widely used mainly due to the processing techniques employed in their manufactme, that allow for the easy use of long fibers, mats and fabrics as reinforcement. Thermosets are also generally more thermally stable than thermoplastics, and these two reasons lead to products with significantly higher mechanical properties which are less affected by thermal variations than thermoplastic composites [1,2,12],... 

Dimer acid-based polyesters being used as thermoplasts, thermoset, and elastomers are used in large quantities as adhesives and coatings. The polyesters, as we have reported herein, may have various commercial applications. Owing to the flexural properties, these low molecular weight linear polyesters of dimer acid may be used as plasticizers providing internal lubrication for various polymers, such as polyimides and inorganic coordination polymers, which may have very poor processibility. 

Injection molding is the most widely used production technique for molding thermoplastics, and is also capable of molding thermosets and elastomers. Injection molding is perhaps the most expensive and corr5>lex process used to produce microstructures in polymers due to the specialized equipment, tooling, and process variables. In an injec-... 

These improvement possibilities are not restricted to injection molds. Thus, in addition to the mold cavities for thermoplastic, thermoset, and elastomer processing, also extrusion molds, slides and jaws, ejector systems, melt control systems and return valves are treated with success. Also for the treatable types of mold materials, the frontiers have been pushed back in recent years. In addition to typical mold steels, nonferrous metals like aluminum or copper alloys can be optimized through different surface and coating technologies. 

Chemical Resistance of Thermoplastics also includes introductory chapters which will enhance the usefiilness of the information to a broader audience. The first of these chapters introduces polymer chemistry, physics and engineering at a fairly elementary level that is easy to read and accessible to technically informed readers without a background in plastics. The chapter begins by providing definitions and a history of polymers. It continues with the classification of different types of polymers, including thermoplastics, thermosets and elastomers. Also covered are properties, stmctures, and examples of commercial polymers as well as processing and polymerization techniques. The chapter ends with a discussion of applications and common trademarks of plastics. 

Plastics can be subdivided into three main categories, thermoplastics, thermosets and elastomers. This distinction is based on both the molecular structure and the processing routes that can be applied. These three classes of materials will now be introduced. 

Styrene-butadiene block copolymers belong to a new class of polymers called thermoplastic elastomers (TPE). Products made from these polymers have properties similar to those of vulcanized mbbers, but they are made from equipment used for fabricating thermoplastic polymers. Vulcanization is a slow and energy-intensive thermosetting process. In contrast, the processing of thermoplastic elastomers is rapid and involves cooling the melt into a rubberlike solid. In addition, like true thermoplastics, scrap from TPE can be recycled. 

Thermoplastic rnbbers (TPR, or elastomers) are another gronp of materials that exhibit the same desirable characteristics as rubber, with the ease of processing of thermoplastics at room temperatnres they behave like a rubbery thermoset material. However, at higher temperatures, they behave like a thermoplastic (i.e., segmented block copolymers of PU, styrenics and polyesters, and olefinics. 

Keywords Additives, Compounding, Deformation of melts, Extrusion foaming. Flow properties, Influences of processing on properties. Injection molding. Plastic melts, Processing of elastomers and thermosets. Processing of fiber composites. Processing of thermoplastics... 

In many applications, moderate to high electrical conduction is required to serve the purpose. In such systems, it is preferred to prepare ICPs-based BLNs or CMPs/NCs/HYBs by incorporation of highly doped forms (or ICPs) inside a variety of polymeric hosts (thermoplasts, thermosets, rubber, elastomer). Many a times, ICPs-based copolymers have also been made to optimize the conductivity, processability, electroactivity, and optoelectronic properties. These copolymers are widely employed in the areas like corrosion inhibition, EMI shielding, ECs, gas sensing, biosensing, energy storage, thermoelectric, antistatics, etc. 

Thermoplastics as well as thermosets and elastomers can be processed with the injection molding process, although for cross-linking polymers modified equipment in machines and adequate molds, which are generally heated to 120 to 180 °C, are needed. Due to the large majority of applications, the following covers primarily molds for thermoplastics, with temperature control between 10 to 120 °C, which can go up to 200 °C for "exotic , highly heat-resistant thermoplastics. 

In the early days of rheological simulation, only the standard injection molding process of thermoplastics had been considered. Today, there are solutions for elastomers, thermosets, liquid silicone resin polymers, and also polymers for the reaction injection molding (RIM) process. Simulation programs have been developed for various materials as well as for various processing techniques on the shell model and are available in all these varieties. 

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