An alternating copolyurea was prepared by the interfacial polycondensation of 1,4‐piperazinedicarbonyl chloride with hexamethylenediamine. Comparison of this alternating copolyurea with the corresponding copolyurea having a random distribution showed that the alternating copolymer had a higher melting point, greater crystallinity, and was somewhat less soluble than the random copolymer. A series of copolyamideurethanes was prepared by the interfacial polycondensation of 2,5‐dimethylpiperazine with terephthaloyl chloride and ethylene bis(chloroformate), various modes of addition of the two diacid chlorides being used. The degree of order developed in these copolyamide–urethanes was postulated from the probable mechanism of the reaction. The directional “crystallinity” or lattice order of the copolymers, as determined from x‐ray diffraction patterns, was cited to support these postulated structures.
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Lyman et al. (1959) studied this question.
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