Polyamides from trans‐4‐octen‐1,8‐dioic and trans‐2‐trans‐6‐octadien‐1,8‐dioic acids

Abstract

SynopsisNovel polyamides from trans-Pocten-l,8-dioic acid (POD) and truns-%trans-&octadien-1,S-dioic acid (2,GODD) ad linear aliphatic diamines or piperasine were prepared in good yields by low-temperature polycondensation. The polymers obtained were investigated by infrared spectroscopy, x-ray diffraction, and differential scanning calorimetry. Polyamides from 4-OD show high molecular weights and crystallinities and T, above 500"K, whereas those from 2,6-ODD are very weakly crystalline and decompose without melting in nitrogen a t 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. HOOCCH2 CH CH,

Unsaturated Polyamides from Bio‐Based Z‐octadec‐9‐enedioic Acid

“…It is worth mentioning that the use of octadec-9-enedioic acid with E configuration would probably have induced an opposite effect by reducing chain flexibility, as can be extrapolated from the higher melting temperature of the polyamide obtained from 1,6-hexanediamine and E-oct-4-enedioic acid (259 8C) comparatively to that of the corresponding saturated polyamide, polyamide-6,8 (240 8C). [24] Due to the presence of rigid cyclohexyl rings in the chains, polyamide 3c presents higher T g and T m than aliphatic polyamide 3a. A similar effect can be found when comparing the thermal properties of the polyamide obtained from 2c (51% of TT isomer) and dodecanedioic acid (polyamide-PACM,12) and of polyamide-6,12: these polymers exhibit melting temperatures of 264 [25] and 212 8C [25] and glass transition temperatures of 125 [25] and 46 8C, [26] respectively.…”