ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Thermal properties of amino acid type polyamides

F. J Carrière and H. Sekiguchi

Laboratoire associéau C.N.R.S. n° 24 — E.P.C.I., 752 31 Paris, Cedex 05

Abstract:  We studied the thermal properties of nylons 4 to 12 using the DSC method. For the determination of melting points, a new technique of thermal treatment was used. It consists of giving a finite number of repeated cooling—heating cycles to polymers just below their melting points before the determination. This treatment allowed to eliminate the diversity of thermal history of various samples and led to "perfect" crystalline structure polymers. The obtained melting points were called "intrinsic" melting points. When this technique was not used, nylons 4 and 5 showed a melting behaviour different from the others because of their thermally degradable nature. While some authors state that odd nylons have no glass transition, we found that every nylon gives two transitions between -10 and +80°C. The glass transition T_g lies between +35 and +85°C. In the case of even nylons, T_g is always followed by a crystallization which is known as cold crystallization for nylon 6. This phenomenon seems to be due to characteristic crystalline structure of even nylons. The study of transitions and of melting points of nylons allowed us to consider a theoretic explanation of the crystalline structure of these polymers.

Full paper in Portable Document Format: 303a281.pdf

Chemical Papers 30 (3) 281–291 (1976)