Thermodynamics of Ring-Opening Polymerization

The entropy changes do not show much dependence of on angle strain. They are susceptible, however, to configurational influences. Sawaada [233] writes the entropy change of polymerization as a function of the probability of ring closure  

---

The thermodynamics of ring opening polymerization was first proposed by Dainton and Ivin [21] in the form of the following expression ... 

Thermodynamics of ring-opening polymerization has been treated in several monographs [53-55],... 

Ivin, K. J., and Saegusa, T., (1984). General Thermodynamic and Mechanistic Aspects of Ring-opening Polymerization . In Ring-Opening Polymerization (Ivin, K. J., and Saegusa, T., eds.), Elsevier Applied Science Publishers, London/New York, pp. 1. 

I 7 Thermodynamics and Kinetics of Ring-Opening Polymerization 1.2.2.2 Monomer-Polymer-Solvent Interactions... 

The ring-opening polymerization of is controUed by entropy, because thermodynamically all bonds in the monomer and polymer are approximately the same (21). The molar cycHzation equihbrium constants of dimethyl siloxane rings have been predicted by the Jacobson-Stockmayer theory (85). The ring—chain equihbrium for siloxane polymers has been studied in detail and is the subject of several reviews (82,83,86—89). The equihbrium constant of the formation of each cycHc is approximately equal to the equihbrium concentration of this cycHc, [(SiR O) Thus the total... 

Rhenium compounds as catalysts, 136, 137, 141, 144, 146, 148, 150 Ring-opening polymerization, 143 catalysts for, 140 thermodynamics of, 156 Rotary engine, 123... 

Quite often in the ring-opening polymerization, the polymer is only the kinetic product and later is transformed to thermodynamically stable cycles. The cationic polymerization of ethylene oxide leads to a mixture of poly(ethylene oxide) and 1,4-dioxane. In the presence of a cationic initiator poly(ethylene oxide) can be almost quantitatively transformed to this cyclic dimer. On the other hand, anionic polymerization is not accompanied by cyclization due to the lower affinity of the alkoxide anion towards linear ethers only strained (and more electrophilic) monomers can react with the anion. 

Raquez J-M, Degee P, Narayan R, Dubois P (2001) Some thermodynamic, kinetic, and mechanistic aspects of the ring-opening polymerization of l,4-dioxan-2-one initiated by A1 (OiPr)3 in bulk. Macromolecules 34 8419-8425... 

Because of its favorable kinetic and thermodynamic properties, norbomene can be polymerized with simple transition-metal halogenides.99 116 Even RuC13, which is not active in other metathesis reactions, is effective in the ring-opening polymerization of norbomene.117118 Developments in the early 1990s include the use of... 

This reaction is thermodynamically controlled, because the polymer containing 1,3-dioxolane rings converts itself to a polyether when allowed to stand at room temperature for several days or heated at 80 °C for a few hours in the presence of an acid catalyst. Similar double ring-opening polymerizations were observed for 2,6,7-trioxabicyclo[2.2.2]octane and its derivatives [86, 87] and for spiro orthoesters and spiro orthocarbonates as well (see Sects. 6 and 7). 

In many instances in cationic ring-opening polymerization, all the reaction steps, however, are reversible. The final composition of copolymer (in equilibrium) is governed then by thermodynamics. Thermodynamic approaches have been developed [305] and recently reviewed [306]. Such thermodynamic approach has been used to analyze the copolymerization of pairs of cyclic acetals (1,3-dioxolane with 1,3-dioxepane and... 

---