Radiation metal coordination polymers

Let us examine some examples of improved service characteristics of metal-polymer friction joints with the help of electrical fields. A metal-polymer joint (MPJ) is a combination of metal and polymer parts operating in coordination [66]. The durability of an MPJ depends on its design, the properties of constituent materials and the operation conditions, including temperature, pressure, mutual displacement velocity, ambient media, physical fields, radiation etc. During operation, an MPJ undergoes certain changes in its material structure, wearing, etc. that impair its performances and life of the joint as a whole (Fig. 4.18, solid arrows). 

In principle, metal-containing polymers represent "oready-for-use" conoposite materials. They possess a full spectrum of polymeric properties enriched by the presence of transition or non-transition metals in the macromolecules. The latter are potentially capable of giving ionic and coordinative cross-links. Their metals provide for electron transfers induced both by an electric field and hi -energy radiations. In addition, they display cohesion and adhesion interactions, etc. 

The chelation leads to a pseudocyclization whereby a coordination network is formed. The structure shown in Equation (28-49) is therefore only one of many possibilities. According to the nature of the metal ion and the molar ratio of metal/PTO, the color varies between yellow (Zr /PTO = 0.35) through orange (Zn /PTO=2) and olive green (Cu /PTO = 0.66) to brown (Ca /PTO = 1) and black (Fe /PTO = 1). White and blue shades are not obtained. The chelated polymers are very flame resistant, especially when chelated with zinc, tin, or iron ions. Mercury ions produce radiation-proof but not fire-proof polymers. 

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