Solid-state polycondensation kinetics

Many studies on the modelling of esterification, melt polycondensation, or solid-state polycondensation refer to the reaction scheme and kinetic data published by Ravindranath and co-workers. Therefore, we will examine the data sources they have used over the years. The first paper concerned with reactor modelling of PET production was published by Ravindranath el al. in 1981 [88], The reaction scheme was taken from Ank and Mellichamps [89] and from Dijkman and Duvekot [90], The kinetics for DEG formation are based on data published by Hovenkamp and Munting [60], while the kinetics for esterification were deduced... 

Chang, T. M., Kinetics of thermally induced solid state polycondensation of poly(ethylene terephthalate), Polym. Eng. Sci. 10, 364-368 (1970). 

Tang, Z., Goa, Q., Huang, N. and Sironi, C., Solid-state polycondensation of poly (ethylene terephthalate) kinetics and Mechanism, J. Appl. Polym. Sci., 57, 473-485 (1995). 

Chang, T. M., Kinetics of thermally induced solid state polycondensation of... 

Pilati, F., Sarti, G. C. and Di Giacomo, B., Chemical kinetics and diffusion in PBT solid state polycondensation. Experiments and theory, J. Appl Polym. ScL, 29, 2873 (1984) (d) Gostoli, C., Pilati, F. and Sarti G. C., presentation given at tlie International Conference on Reactive Processing of Polymers, Strasbourg, France, 1984, Preprints, p. 49 (e) Pilati, F., Gostoli, C. and Gostoli, G. L., Polym. Proc. Eng., 4, 303 (1986). 

Sun YM, Shieh JY. Kinetic and property parameters of poly(ethylene naphthalate)synthesized by solid-state polycondensation. J Appl Polym Sci2001 81(9) 2055-61. 

Gostoli G, Pilati F, Sarti G and Giacomo B (1984) Chemical kinetics and diffusion in poly(butylene terephthalate) solid-state polycondensation Experiments and theory, J Appl Polym Sci 29 2873-2887. 

Flory outlined [3] that the definition of polycondensation is necessarily based on kinetic aspects and not on the structure of polycondensates, because numerous polycondensates can also be prepared by ROP which usually proceeds as chain-growth polymerization. Flory s definition of step-growth polymerization is limited to polycondensations and polyadditions in the melt or in solution, and does not include solid-state polycondensations. Hory s definition of step-growth polymerizations is based on point 1. 

According to the principles of polycondensation, all of the above reactions will also take place during SSP. The conditions for the latter, however, are different as this process is carried out at lower temperatures in a non-homogeneous environment. In order to examine the kinetics of SSP, some assumptions have to be made to simplify the analysis. These are based on the idea that the reactive end groups and the catalyst are located in the amorphous regions. Polycondensations in the solid state are equilibrium reactions but are complicated by the two-phase character of the semicrystalline polymer. 

The thermal polycondensation of dihydroxy(metallo)phthalocyanines to cofacially stacked polymer in the solid state as example of a type III polymers [equation (7)] is topotactic and under topochemical control, which means that well-defined intermolecular distances and interactions in the lattice control the reaction [56]. Following a kinetic study the fraction of unreacted -OH end groups X over time does not obey a first order kinetics (X = exp(— 2 ), M = Si, Ge, Sn n = 50-200). 

Analytical and kinetic studies of photo-oxidation in the solid state of phenolic resins (phenol-formaldehyde polycondensates) (4.36) show that photoreaction involves two processes [1845] ... 

The deep insight in the structure of the chains is often accompanied by little attention to their association in the solid state on the other hand, some authors are only concerned by the material without paying great attention to the macromolecule itself. However, some articles associate these two aspects, as did Purukawa et al. [117], who prepared polysiloxane-6-polyamide by solution polycondensation (xylene/NMP) of 3,3, 4,4 -diphenylsulfonetetracarboxylic dianhydride, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and Qf,w-diammo-poly-siloxane (the synthesis belongs to the techniques listed in Section 2.3). The chains were analyzed by H, and Si NMR, as well as by infrared spectroscopy, whereas the spin-lattice relaxation time was measured by solid-state NMR. A kinetic study of the imidization was carried out in NMP solution it showed that the value of the activation energy is partly determined by the solvation of the amide groups and polyamic acids. 

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