Statistical copolymers crystallization thermodynamics

Statistical copolymers refer to a class of copolymers in which the distribution of the monomer counits follows Markovian statistics [1,2]. In these polymeric materials, since the different chemical units are joined at random, the resulting polymer chains would be expected to encounter difficulties in packing into crystaUine structures with long-range order however, numerous experiments have shown that crystallites can form in statistical copolymers under suitable conditions [2], In this section, we will discuss the effects of counit incorporation on the solid-state structure and the crystallization kinetics in statistical copolymers. A number of thermodynamic models, which have been proposed to describe the equilibrium crystallization/melting behavior in copolymers, vill also be highlighted, and their applicability to describing experimental observations will be discussed. 

Thus far, we have discussed a number of key experimental observations regarding the effects of counit incorporation on the solid-state structure and the crystallization kinetics in statistical copolymers. In order to better quantify these experimental observations, various thermodynamic models have been proposed. Rory s model, as outlined in Section 11.2.1, correctly describes the equilibrium melting behavior of copolymers in the limit of complete comonomer exclusion however, it is often found to be inadequate at predicting experimentally accessible copolymer melting temperatures [11-14]. An alternative was proposed by Baur [91], where each polymer sequence is treated as a separate molecule with an average sequence length in the melt given by [91] ... 

The principles of polymer fractionation by solubility or crystallization in solution have been extensively reviewed on the basis of Hory-Huggins statistical thermodynamic treatment [58,59], which accounts for melting point depression by the presence of solvents. For random copolymers the classical Flory equation [60] applies ... 

Flory PJ (1954) Theory of crystallization in copolymers. Trans Faraday Soc 51 848-857 Flory PJ (1956) Statistical thermodynamics of semi-fiexible chain molecules. Proc R Soc London A234 60-73... 

Flory PJ (1941) Thermodynamics of high polymer solutions. J Chem Phys 9(8) 660 Flory PJ (1942) Thermodynamics of high polymer solutions. J Chem Phys 10(1) 51-61 Flory PJ (1953) Principles of polymer chemistry. Cornell University Press, Ithaca Flory PJ (1955) Theory of crystallization in copolymers. Trans Faraday Soc 51 848-857 Flory PJ (1956) Statistical thermodynamics of semi-flexible chain molecules. Proc R Soc Lond A Math Phys Sci 234(1196) 60-73... 

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