Polymerization high temperature melt method

Polycarbonates are manufactured via interfacial polymerization or through a melt esterification process. The properties of polycarbonate can differ greatly based on the method of polymerization. Specifically, the molecular weight distributions created by the two methods differ because of kinetic effects. Polycarbonates manufactured via interfacial polymerization tend to be less stable at high temperatures and less stiff than those produced via melt esterification, unless proper manufacturing precautions are taken. Therefore, when choosing a polycarbonate resin grade for a specific application, it is important to know the method by which it was produced. Either polymerization method can be performed as a continuous or batch process. 

Details of this experiment may be found in Ref. 1. The interfacial polymerization method to prepare polyamides involves the reaction of a diacid dichloride with a diamine between two immiscible liquids as the reaction zone (with or without stirring). The method is useful where the reactants are sensitive to high temperature and where the polymer degrades before the melt point is reached (as in melt polymerization techniques). 

LC polymers of the ester type have been the most widely synthesized because they can be prepared by low temperature solution polymerization methods and melt transesterification reactions from available or readily attainable monomers. High temperature ester interchange polymerization, however, is somewhat limited in usefulness because it often leads to polymer structures of poorly defined sequence... 

Partly aromatic copoly(amide)s prepared by conventional processes have triamine contents greater than 0.5%. This effects a deterioration in the product quality and to problems in preparation by a continuous method. For example, dihexamethylenetriamine, formed from HMD is used in the preparation. Copoly(amide)s with a low trianune content have the same solution viscosity but lower melt viscosities compared with products of the same composition which have a higher triamine content. The processability and the product properties are significantly improved by a low triamine content. The dimerization of the diamine can be suppressed by using special methods of polymerization. Short residence times in the high-temperature stage of the polycondensation process suppress the formation of triamines. ... 

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