Non-equilibrium polycondensation

Non-equilibrium polycondensation can be characterized by a mun-ber of advantages among the polycondensation processes. These are the absence of exchange destructive processes, high values of constants of speed of growth of pol5mieric chain, et cetera. However, some questions of nonequilibrium polycondensation still remain unanswered the mechanism and basic laws of formation of copolymers when the possibility of combination of positive properties of two, three or more initial monomers can be realized in high-molecular product. 

V. V. Korshak and S. V. Vinogradova, Non-Equilibrium Polycondensations (in Russian), Nauka, Moscow, 1972. 

Each class offers possible sub-classification according to the chain-growth mechanism (such as radical polymerization, ionic polymerization, addition polymerization, migratory polymerization, equilibrium and non-equilibrium polycondensation, and etc.) and according to initiation or activation mechanisms (peroxide, radiative, photonic and catalytic initiation or activation by specific curing agents). 

M. Gordon and G. R. Scantlebury, Trans. Faraday Soc., 60, 605, (1964). Theory of Ring-chain Equilibrium in Branched Non-Random Polycondensation Systems. 

Interfacial polycondensation can yield polymers with high molecular weights at high reaction rates. Since the interfacial technique is a non-equilibrium method, the critical dependence of high molecular weight on exact stoichiometric equivalence between diol and dichloridate inherent in bulk and solution methods is removed. The limitation of this method is the hydrolysis of the acid chloride in the alkaline aqueous phase. 

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. 

ATR-FTIR (attenuated total reflection infrared) Olefin polymerization (ethene/1-hexene) [70] Polycondensation of diols and carbamic acid, equilibrium of isocianates with alcohols [71] Non-invasive, well suited for polycondensation/Poor fiber-optic transmission, not well suited for waterborne polymerization All polymerization techniques... 

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