S-Caprolactam polymerization

Figure 4.1. Flowsheet of production of a reactive mixture by activated anionic s-caprolactam polymerization (explanations of numbers are in the text).

Investigations on solidity and stability of XL-XLVl compounds at the stage of s-caprolactam polymerization were carried out to determine compatibility and stability of bis -(1 , 8 - benzoilene - 1,2 - benzimidazoles) and bis - (1 , 8 - naphthoilene - 1,2 -benzimidazoles) in reactive PCA mass. Obtained coloured polymer was investigated visually to homogeneity of solid solution, its solubility in H 2 SO 4, in the mixture of 80% formic and trifluoro - acetic acids in ratio 1 1 and in in - cresol. Ability of PCA melt to form into a fibre, and also molecular masses of dyed and undyed polymer with average viscosity were defined too. 

Hydrolytic polymerizations are the smoothest of all three types of polymerization reactions because the growing species are less activated than in either cationic or anionic polymerizations. Many commercial processes utilize it in s-caprolactam polymerizations. Formation of irregular structures, however, and even crosslinked material was detected. In addition, at elevated temperatures deamination and decarboxylation of polycaprolactam can take place [150] Such reactions can result in formations of ketones and secondary amine groups. The ketones, in turn, can react with amines and form Schiff bases. This leads to branching and crosslinking. 

Begishev, V. P. Volpert, V. A. Davtyan, S. P. Malkin, A. Y. 1985. On some Features of the Anionic Activated s-Caprolactam Polymerization Process under Wave Propagation Conditions, Dokl. Phys. Chem. 279, 1075-1077. 

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See also in sourсe #XX -- [ ]

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