Rubber Vulcanization And Plastics

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Chapter 1. Introduction Wide spread application of rubber vulcanization and plastics began 200 years after the invention of these incredible materials. Each year the properties of rubber and plastics continue to improve and the amount of research also increases. In recent years the main challenge has been trying to refine the properties of these materials so that they lie somewhere between plastics and elastomers. This outcome, ideally, would be highly desirable for a wide range of applications. In the begin of 1930s Carothers was successful in synthesizing poly amides, afterwards, based on his developments, a German company started creating and working on a new type of materials with properties like polyamides. As a result were obtained…show more content…
It’s softens when heated similar to an elastomer and solidifies when cooled just as plastic does. This makes it suitable for melt-processing manufacturing methods such as extrusion molding and others. The principal difference between thermoset elastomers and thermoplastic elastomers is the type of crosslinking bond in their structures. In fact, crosslinking is a critical structural factor which contributes to impart high elastic properties. TPE materials have the potential to be recyclable since they can be molded, extruded and reused like plastics, but they have typical elastic properties of rubbers which are not recyclable owing to their thermosetting characteristics. TPE also requires little or no compounding, with no need to additional reinforcing agents, stabilizers or cure systems. With more than 30 years of commercial product development, one thermoplastic elastomer clearly stands out for its ability to provide a multitude of physical property combinations for a wide variety of process in applications: thermoplastic polyurethane (TPU). TPU is a polyurethane elastomer that is fully thermoplastic. There are a lot of different types of polyurethanes materials in different states and shapes. But one thing is common to them all containment of urethane group –NCO-O . Scheme 1. Basic reaction scheme for urethane…show more content…
Due to this; thermal stability is very low when compared to other polymer materials which consist of chemical bonding between molecules or to rubber vulcanizates. Furthermore, it is very critical to understand thermal degradation processes of polyurethanes in order to determine the optimum conditions for manufacturing and designing new materials as well as for the processing polyurethane materials. It’s important to mention that thermal degradation goes through various steps within subsequent phases of the polyurethanes. At a room temperature the hard and soft segmented areas of two phased polyurethane structures are incompatible. When phase separation occurs alongside increasing temperature, especially upon reaching the melting point of HS polymer, a homogeneous viscous melt could form. For most polyurethane materials thermal degradation starts at the melting point of HS, while all mechanical properties reduce with dissolving of the HS area in the SS area. For applications where the applied temperature is discrete through the material thickness, it indeed becomes very difficult to predict the properties

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