Lattice Model of Equilibrium Polymerization. IV. Influence of Activation, Chemical Initiation, Chain Scission and Fusion, and Chain Stiffness on Polymerization and Phase Separation

Published

December 1, 2003

Author(s)

J Dudowicz, Karl Freed, Jack F. Douglas

Abstract

The influences of thermal activation, chemical initiation, chain fragmentation and chain stiffness on basic thermodynamic properties of equilibrium polymerization solutions is systematically investigated using a Flory-Huggins type lattice model. The properties treated include the average chain length L, extent of polymerization [Phi], Helmholtz free energy F, configurational entropy S, specific heat C_v, polymerization transition temperature T_p, osmotic pressure [Pi} and second and third virial coefficients A₂ and A₃. The dependence of the critical temperature T_c and critical composition [phi] (volume fraction of associating species) on the enthalpy [Δ]h_p and entropy [Δ]s_p of polymerization and on the strength [xi]_FH of the FH effective monomer-solvent van der Waals interaction ([Chi] = [epsilon]_FH / T is also analyzed as an illustration of the stong coupling between phase separataion and polymerization. For a given ploymerization model, both T_c and [phi]_c, normailized by their values in the absence of polymerization, are functions of the dimensionless sticking energy h_[epsilon] [identical to] (![Δ]h_p / R) / (2[epsilon]_FH) (where R is the gas constant) and [Δ]s_p. Our critical comparison of free association, activated association, and chemical initiation models of equilibrium polymerization is specialized to systems that polymerize upon cooling, but the general theory also applies for polymerization on heating, essential thermodynamic properties, critical phenomena, and polymerization transitions.

Citation

Journal of Chemical Physics

Volume

119

Issue

No. 23

Pub Type

Journals

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Keywords

chain fission, chain fission, critical composition, critical temperature, equibrium polymerization, living polymers, nanoparticle clustering, thermodynamic properties, virial coefficients

Citation

Dudowicz, J. , Freed, K. and Douglas, J. (2003), Lattice Model of Equilibrium Polymerization. IV. Influence of Activation, Chemical Initiation, Chain Scission and Fusion, and Chain Stiffness on Polymerization and Phase Separation, Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=852246 (Accessed April 19, 2024)