Thermoplastics and Thermosetting plastics

A lot of molding engineers and technical university students are left wanting for the knowledge about Thermoplastics and Thermosetting plastics differences. If you have  been looking for some similar information, then worry no more, this post is going to explain everything in detail. By the way, I would really appreciate some sort of feedback from you after you finish reading this post on Polymer Types and Processes used for the manufacturing for each of these. Do not feel shy to leave a little comment at the bottom of this post by using the comment form. If you really like this post, then please remember to share it on your Facebook and other social accounts. Buttons are provided below the article for this purpose, just press the button as a way to thank me for this post. If you are just starting out and have no idea about plastics and polymers, then read the post What Is A Polymer before reading this post.

All thermoset plastics are self-extinguishing. Among thermoplastics, nylon, polyphenylene oxide, polysulfone, polycarbonate, poly(vinyl chloride), chlorinated polyether, poly(chlorotrifluoroethylene) and fluorocarbon polymers have self-extinguishing properties. Compression and transfer molding are the most common methods of processing thermosetting plastics. For thermoplastics, the more important processing techniques are extrusion, injection, blow molding, and calendaring; other processes are thermoforming, slush molding, and spinning. More recently, modified machinery and molding compositions have become available to provide the economics of thermoplastic processing to thermosetting materials. Injection molding of phenolics and other thermosetting materials are such examples. Nevertheless, it is still a widespread practice in industry to distinguish between thermoplastic and thermosetting resins.
Compression and transfer molding are the most common methods of processing thermosetting plastics. For thermoplastics, the more important processing techniques are extrusion, injection, blow molding, and calendaring; other processes are thermoforming, slush molding, and spinning.
The image below should give you a fairly good idea of what is the difference between Thermoplastics and Thermosetting plastics on base of their linking structures.

Thermoplastic resins consist of long polymer molecules, each of which may or may not have side chains or groups. The side chains or groups, if  present, are not linked to other polymer molecules (i.e., are not cross-linked). Thermoplastic resins, usually obtained as a granular polymer, can therefore be repeatedly melted or solidified by heating or cooling. Heat softens or melts the material so that it can be formed; subsequent cooling then hardens or solidifies the material in the given shape. No chemical change usually takes place during this shaping process.
In thermosetting resins the reactive groups of the molecules from cross-links between the molecules during the fabrication process. The cross-linked or “cured” material cannot be softened by heating.
Thermoset materials are usually supplied as a partially polymerized molding compound or as a liquid monomer–polymer mixture. In this uncured condition they can be shaped with or without pressure and polymerized to the cured state with chemicals or heat.
With the progress of technology the demarcation between thermoplastic and thermoset processing has become less distinct. For thermosets processes have been developed which make use of the economic processing characteristics or thermoplastics. For example, cross-linked polyethylene wire coating is made
by extruding the thermoplastic polyethylene, which is then cross-linkedd (either chemically or by irradiation) to form what is actually a thermoset material that cannot be melted again by heating.
New plastics, such as the Grilamid TR90, are being developed everyday. As a result the manufacturing industry is accepting both Thermoplastics and Thermosetting plastics into the Plastic Injection Mold Design for Molding Plastic Components. Make sure that you bookmark the site to get updated information for various polymers.