Abstract: | The sequence distribution of repeating units of copolyamides from different diamines with isophthaloyl or terephthaloyl chlorides and dithiophenyl adipate have been investigated either by interfacial or solution methods to aim at the sequence control of the copolyamides by solvents. Copolycondensation of dithiophenyl adipate and isophthaloyl chloride with m-xylylenediamine in various solvents yielded copolyamides having different compositions of repeating units. Aprotic polar solvents produced random copolyamides having the same compositions as feed ratios of the comonomers, while nonpolar solvents yielded copolyamides rich in isophthaloyl units. Also the sequence distribution of the copolyamides from m- and p-phenylenediamines with isophthaloyl chloride was affected by solvents; nonpolar solvents produced copolyamides having a less-random and block character of the repeating units either by interfacial or solution methods. |