Polymer resin tungsten

Dicyclopentadiene is also polymerized with tungsten-based catalysts. Because the polymerization reaction produces heavily cross-Unked resins, the polymers are manufactured in a reaction injection mol ding (RIM) process, in which all catalyst components and resin modifiers are slurried in two batches of the monomer. The first batch contains the catalyst (a mixture of WCl and WOCl, nonylphenol, acetylacetone, additives, and fillers the second batch contains the co-catalyst (a combination of an alkyl aluminum compound and a Lewis base such as ether), antioxidants, and elastomeric fillers (qv) for better moldabihty (50). Mixing two Uquids in a mold results in a rapid polymerization reaction. Its rate is controlled by the ratio between the co-catalyst and the Lewis base. Depending on the catalyst composition, solidification time of the reaction mixture can vary from two seconds to an hour. Similar catalyst systems are used for polymerization of norbomene and for norbomene copolymerization with ethyhdenenorbomene. 

The metathesis polymerisation of dicyclopentadiene, an inexpensive monomer (commercially available cyclopentadiene dimer produced by a Diels-Alder addition reaction containing ca 95 % endo and ca 5 % exo form), leads to a polymer that may be transformed into a technically useful elastomer [144-146, 179] and thermosetting resin [180,181]. The polymerisation has characteristics that make it readily adaptable to the reaction injection moulding ( rim ) process [182], The main feature of this process comes from the fact that the polymerisation is carried out directly in the mould of the desired final product. The active metathesis catalyst is formed when two separate reactants, a precatalyst (tungsten-based) component and an activator (aluminium-based) component, are combined. Monomer streams containing one respective component are mixed directly just before entering the mould, and the polymerisation into a partly crosslinked material takes place directly in this mould (Figure 6.5) [147,168,183-186],... 

Use Determination of tungsten and sulfates, polymer and dye intermediate, corrosion inhibitor, epoxyresin hardening agent, isocyanate resins, polyamides. 

NFPA Health 3, Flammability 1, Reactivity 0 Uses Curing agent for cast PU elastomers, food-contact PU resins epoxy resin curing/hardening agent corrosion inhibitor intermediate for paints, dyes, polymers isocyanate resins polyamides determination of tungsten and sulfates curing system additive for bisphenol A-ep-ichlorohydrin epoxies for food contact antioxidant in food-contact rubber articles for repeated use... 

One non-oxide fibre that receives attention is the group based on silicon carbide (e.g. Nicalon , Nippon Carbon), which is available as cf tow for use in high temperature rigid composites with either polymer-based resin or metal matrices such as tungsten. 

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