High-temperature polymer coordination

Ferrocene fer-6- Sen [ferro- -F cycV -F -ene] (1952) (dicyclopentadienyl iron) n. (C5H5)2pe. A coordination compound of ferrous iron and cyclopentadiene, soluble in PVC and stable to 400°C. Its uses include smoke suppression, a curing agent for silicone resins, an intermediate for high-temperature polymers, and an ultraviolet absorber. Wickson EJ (ed) (1993) Handbook of polyvinyl chloride formulating. John Wiley and Sons Inc., New York. 

Reviews containing substantial amounts of data on metallorganic ring-forming polymerizations were found under chelate polymers (7, 18, 23, 31, 33) coordination polymers (5, 6, 9-12, 19, 20, 22, 24, 32, 35) metallorganic polymers (J, 17, 25) and high-temperature polymers (/, 2, 4, 26,28). Reviews and books on inorganic polymers were also useful. 

By the time the concentration of monomer is low, the back-skip of the polymer chain to the less-hindered site is faster than the formation of the high-energy alkene coordinated intermediate (IV). For this reason, at low propene concentrations and elevated temperatures isotactic sequences are formed. The probability of monomer coordination at the aspecific site (IV) is enhanced when the propene concentration increases. The consequence is that single stereoerrors [mrrm] are introduced in the isotactic polymer chain. 13C-NMR was able to prove the mechanism because a... 

The high thermal stability of zeolites and related micro-porous solids is one of their most attractive features. Whilst it Is clear that materials with organic components cannot withstand ultra-high temperatures, quite respectable compositional stability can be achieved. Thus the [Er(TMA)] polymer mentioned above shows no weight loss in its TGA curve before 550°C. However for porous solids another key issue is that of structural stability. Many open framework coordination polymers lose their crystalline structure upon mild heating, or even evacuation, through loss of guest molecules. 

In view of the high thermal stability of monomeric chelation compounds, coordination polymers were expected to be promising for use at high temperatures. This has not proved to be the case. Thermal stabilities arc usually lower than for low molecular weight materials. In addition, if tlie polymerization goes beyond a few monomer units, the materials tend to become insoluble and infusible so they cannot be fabricated into useful items See Chelation Compounds. 

---