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Left: individual linear polymer chains Right: Polymer chains which have been cross linked to give a rigid 3D thermoset polymer. In materials science, a thermosetting polymer, often called a thermoset, is a polymer that is obtained by irreversibly hardening ("curing") a soft solid or viscous liquid prepolymer (). [1]
In this state, thermoplastics may be reshaped, and are typically used to produce parts by various polymer processing techniques such as injection molding, compression molding, calendering, and extrusion. [3] [4] Thermoplastics differ from thermosetting polymers (or "thermosets"), which form irreversible chemical bonds during the curing process ...
Thermoplastics do not undergo chemical change in their composition when heated and thus can be molded repeatedly. Examples include polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). [16] Thermosets, or thermosetting polymers, can melt and take shape only once: after they have solidified, they stay solid. [17]
The benefit of using thermoplastic elastomers is the ability to stretch to moderate elongations and return to its near original shape creating a longer life and better physical range than other materials. [1] The principal difference between thermoset elastomers and thermoplastic elastomers is the type of cross-linking bond in their structures ...
The research group led by Ludwik Leibler demonstrated the operating principle of vitrimers at the example of epoxy thermosets. Epoxy thermosets can be represented as vitrimers, when transesterification reactions can be introduced and controlled. In the studied system, carboxylic acids or carboxylic acid anhydrides must be used as hardeners. [13]
Thermoplastics regain their solid properties upon cooling and can thus be reshaped by polymer processing methods such as extrusion and injection moulding and they can also be recycled. [4] Examples of thermoplastic polymers are polystyrene, polycarbonate, polyethylene, nylon, Acrylonitrile butadiene styrene (ABS), etc.
A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents , acids , and bases . The best known fluoropolymer is polytetrafluoroethylene under the brand name "Teflon," trademarked by the DuPont Company.
Common polymers like epoxy and phenolic are examples of thermosetting plastics while nylon, polyethylene, and polystyrene are thermoplastic. [1]: 242 Until comparatively recently, plastic springs were not possible, but advances in polymer properties make them now quite practical. Applications include buckles for anchoring and disconnecting ...