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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]
A thermoset polymer matrix is a synthetic polymer reinforcement where polymers act as binder or matrix to secure in place incorporated particulates, fibres or other reinforcements. They were first developed for structural applications, [ 1 ] such as glass-reinforced plastic radar domes on aircraft and graphite - epoxy payload bay doors on the ...
Crosslinking generally involves covalent bonds that join two polymer chains. The term curing refers to the crosslinking of thermosetting resins, such as unsaturated polyester and epoxy resin, and the term vulcanization is characteristically used for rubbers. [1] When polymer chains are crosslinked, the material becomes more rigid.
Thermoplastic polymer materials melt upon heating and become viscous liquids, whereas thermosetting polymer materials remain solid as a result of cross-linking. [2] Thermoplastics consist of long polymer chains that are stiff at service temperatures but become softer with increasing temperature.
The polymer chains associate by intermolecular forces, which weaken rapidly with increased temperature, yielding a viscous liquid. 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 .
It works by forming cross-links between sections of the polymer chain which results in increased rigidity and durability, as well as other changes in the mechanical and electrical properties of the material. [2] Vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible.
This so-called phase separation between both blocks can be more or less important, depending on the polarity and the molecular weight of the flexible chain, the production conditions, etc. The crystalline or pseudo crystalline areas act as physical cross-links , which account for the high elasticity level of TPU, whereas the flexible chains ...
Polymer morphology is a microscale property that is largely dictated by the amorphous or crystalline portions of the polymer chains and their influence on each other. Microscopy techniques are especially useful in determining these microscale properties, as the domains created by the polymer morphology are large enough to be viewed using modern ...