Initiation in plasma

The energy of the plasma is sufficient to produce poorly defined branched or even cross-linked products. In the presence of polymerizing monomers, even N2, H20, CO, C02, etc. can be incorporated in polymer chains [322], 

Initiation can be most effectively studied in systems with the smallest number of elementary steps in the polymerization reaction. This requirement is fulfilled in living systems (without termination and transfer) with monomers which do not generate polymer chains. By eliminating propagation (or suppressing it to dimerization) kinetically relatively simple systems can be obtained which are suitable for the application of convenient analytical methods. 

Schulz and Hocker [323] have studied the behaviour of compounds of the general formula 

R permits conjugation (for example 1,4-phenylene), electron addition to the double bond leads to an increase in electron density even at the other double bond. The negative charge is distributed over the whole molecule which may be regarded as a more complicated allylic ion. Under these conditions electron transfer to the other double bond is strongly hindered with Li it does not occur at all while with Na and K it takes place mainly only after dimerization of the monoradical anion. 

When conjugation between the two double bonds is interrupted by a substituent R, electron transfer to the other double bond is only insignificantly hindered. Important data on donor-acceptor interactions between monomer and metal, and on the effects of R, solvents and temperature on electron transfer [scheme (86)] can be derived from the rate of generation and composition of the products. 

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