POLYAMIDES FROM TRANS-4-OCTEN-1,8-DIOIC AND TRANS-2-TRANS-6-OCTADIEN-1,8-DIOIC ACIDS

Novel polyamides from trans-4-octen-1,8-dioic acid (4-OD) and trans-2-trans-6-octadien-1,8-dioic acid (2,6-ODD) ad linear aliphatic diamines or piperazine were prepared by low-temperature polycondensation. The polymers obtained were investigated by IR spectroscopy, x-ray diffraction, and differential scanning calorimetry (DSC). Polyamides from 4-OD show high molecular weights and crystallinities and T//m above 500 K, whereas those from 2,6-ODD are very weakly crystalline and decompose without melting in nitrogen at temperatures higher than 550 K. DSC studies revealed in the case of 4-OD polymers with odd diamines, a multiple peak phenomenon in the melting region, strongly dependent from the heating rate. Some hypotheses consistent with this behavior are briefly discussed, and it is concluded that the phenomenon arises from melt recrystallization occurring during the DSC scan.