Thermodynamics of Macrocyclization

In the case of back-biting and a high molar mass of the linear polymer fraction, the expression for the corresponding equilibrium constant reads  

Kp = equilibrium constant of propagation Ke = equilibrium constant of end-to-end cycylization Kbb, Kbb = equilibrium constants of back-biting Kse = equilibrium constant of segmental exchange 

Theoretical considerations based on the Jacobson-Stockmayer theory [75, 76] led to the conclusion that, for nonstrained cycles in 0 solvent  

One important factor from a practical point of view is the crihcal concentration of the macrocycles (i.e. Ey[M(y)]eq), the parameter which indicates the concentration of monomer which eventually will be converted into the macrocycHc fraction. 

Cyclic oligomers are usually considered to be a contamination of the high polymers, as their presence results in a deterioration of the mechanical properties of 

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Thus, we first discuss thermodynamics, paying attention to features that are important for polymer synthesis (e.g., dependence of equilibrium monomer concentration on polymerization variables) then we describe kinetics and thermodynamics of macrocyclization, trying to combine these two related problems, usually discussed separately. In particular we present the new theory of kinetic enhancement and kinetic reduction in macrocyclics. Thereafter, we describe the polymerization of several groups of monomers, namely cyclic ethers (oxiranes, oxetanes, oxolanes, acetals, and bicyclic compounds) lactones, cyclic sulfides, cyclic amines, lactams, cyclic iminoethers, siloxanes, and cyclic phosphorus-containing compounds, in this order. We attempted to treat the chapters uniformly we discuss practical methods of synthesis of the corresponding polymers (monomer syntheses and polymer properties are added), and conditions of reaching systems state and reasons of deviations. However, for various groups of monomers the quality of the available information differ so much, that this attempt of uniformity can not be fulfilled. 

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