THERMAL-BEHAVIOR OF POLY(ALPHA-N-ALKYL BETA-L-ASPARTATE)S

A series of poly(alpha-n-alkyl beta-L-aspartate)s (n being the number of carbon atoms in the linear alkyl side chain, with n = 1, 2, 4, 6, 8 , 12, 18 and 22), was studied by differential scanning calorimetry and thermogravimetric analysis. The effect of the length of the alkyl gro up on thermal properties such as stability, melting and crystallizatio n of side chains, was investigated. For the polymers with n greater th an or equal to 12, two endothermic peaks at T-1 and T-2 were detected separating three distinct phases A, B and C. The peak at T-1 correspon ds to the melting of the crystallized paraffinic side chains (transiti on A-B), and the peak at T-2 may be attributed to a transition (B-C), implying a liquid crystal phase.