Polyacetal POM

Commercial polymers of formaldehyde are also produced using cationic polymerization. The polymer is produced by ring opening of trioxane. Since the polyacetal, POM, is not thermally stable, the hydroxyl groups are esterified (capped) by acetic anhydride (structure 5.22). These polymers are also called poly(methylene oxides). The commercial polymer is a... 

Another stable polyacetal (POM Celcon) is produced by the cationic copolymerization of a mixture of trioxane and dioxolane (structure 5.23). 

In this group, there are acrylics, polymethylmethacrylate (PMMA) acrylonitrile butadiene styrene (ABS), aromatic polyamides (PI), cellulosics (CA, CAB, CAP, CN), ethylene vinyl acetate (EVA), fluoroplastics (Teflon, PTFE and FEP), Nylons - polyamides - (PA), polyacetals (POM), polyethylethylketone (PEEK), polybutene-1 (PB-1), polycarbonate (PC), polyesters - thermoplastic - (PETP, PBT, PET),... 

For polyacetal (POM), viscosity versus shear rate data were obtained from two sources [57,58]. One source was the renowned book on polyacetals by Barker and Price [57], whereas the other source was a research paper by Pritchard and Wissbrun [58]. Only 24 data points were analyzed and the master rheograms as shown in Fig. 4.19 were generated [56]. Even with limited data, two distinct master rheograms were revealed—one for linear polyacetal and the other for branched polyacetal. This is not an unexpected situation and is. similar to that observed earlier for polethylenes wherein HOPE (linear PE) and LDPE (branched PE) have two distinct master rheograms. 

PTM Engineering Plastics, is a planned joint venture of Ticona and affiliate Polyplastics, with Japan s Mitsubishi Gas Chemical Company. They are to build a world-scale, 60,000 tpa plant for polyacetal (POM) resins in China, due to start-up in 2004. Mitsubishi already operates a 50,000 tpa POM plant in Japan. 

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