Vulcanization description

These various operations, together with the vulcanization of gutta-percha, will now be described successively and in detail—premising that in this country tho manufacture is confined to two or three companies, which work the various patents secured from time to time by Mr, Hancock and others. A simple description of the manufacture,1 as conducted by the London Gutta-Percha Gompany, will, therefore, embrace all that is really important in the different operations. 1 ... 

Description Solvent solutions, latexes, and vulcanizing type Solvent solutions, some water dispersions most are black, some gray and red Solvent system, latex Solvent solution... 

Description Two-part liquid or paste Solvent solution heat or RT-curing and pressure sensitive RT-vulcanizing solvent-free pastes Latexes and solvent solutions, often compounded with resins, metallic oxides, fillers, etc. 

Indeed, when subjected to an external traction, the molecular chains dispose parallel to the macro-displacement and because of the crosslinks introduced by the vulcanisation, they cannot slide back to the initial disordered state. By removing the external loading, the system tends towards the initial state of maximum entropy and the specimen recovers the initial length. In this case, the external supplied energy is totally recovered. The behavior of a real elastomer slightly differs from this simplified description. Indeed, even if the elastomer is vulcanized, the macromolecules can partially slide one onto each other with a dissipation of the mechanical energy. 

We started this chapter with a description of the fundamental differences between thermoplastic and thermoset materials we will end it with an example of a subtle blend of their respective properties. A disadvantage of the three-dimensional network of EPDM, but actually of all thermoset materials, is the lack of recyclability. Crosslinked EPDM, both the waste from production and after use, cannot be processed in the melt again like thermoplastics. Reclaiming technologies have been developed for vulcanized mbber, degrading part of the network via high-temperature and shear treatment, but these technologies are less effective for EPDM vulcanizates, probably because the EPDM chains are so stable. A break-... 

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