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Polymer stabilizers ... This is of particular concern where polymers are in direct contact with metal, such as in wiring and cable. ... Thermal (or heat) stabilizers ...
Hindered amine light stabilizers (HALS) are chemical compounds containing an amine functional group that are used as stabilizers in plastics and polymers. [1] These compounds are typically derivatives of tetramethylpiperidine and are primarily used to protect the polymers from the effects of photo-oxidation; as opposed to other forms of polymer degradation such as ozonolysis.
Antiozonants prevents or retards the degradation of polymers caused by ozone (ozone cracking) sequestrants, forming chelate complexes and inactivating traces of metal ions that would otherwise act as catalysts; ultraviolet stabilizers are used to protect polymers from effects of ultraviolet radiation and come to 2 main types.
Styrene, for example, is distilled at temperatures above 100 °C whereupon it undergoes thermal polymerisation at a rate of ~2% per hour. [1] This polymerisation is undesirable, as it can foul the fractionating tower ; it is also typically exothermic , which can lead to a runaway reaction and potential explosion if left unchecked.
Polyelectrolytes are charged polymers capable of stabilizing (or destabilizing) colloidal emulsions through electrostatic interactions. Their effectiveness can be dependent on molecular weight, pH, solvent polarity, ionic strength, and the hydrophilic-lipophilic balance (HLB).
The polymer beads that result can range in size from 100 nm to 5 mm. The size is controlled by the stirring speed, the volume fraction of monomer, the concentration and identity of the stabilizers used, and the viscosities of the different components. The following equation derived empirically summarizes some of these interactions:
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 ...
Polysiloxane, siloxane-based polymers available in a wide range of physical states—from liquids to greases, waxes, resins, and rubbers. Due to perfect thermal stability (thanks to silicon, Si) uses of this material include antifoam and release agents, gaskets, seals, cable and wire insulation, hot liquids and gas conduits, etc.