Nucleating agent for poly(L‐lactic acid)—An optimization of chemical structure of hydrazide compound for advanced nucleation ability

Abstract A series of compounds having hydrazide groups was prepared and evaluated as nucleating agent for poly( L ‐lactic acid) by differential scanning calorimetry. Hydrazide compounds derived from benzoic acid, 2‐hydroxybenzoic acid, 3‐ tert ‐butylbenzoic acid, and 2‐aminobenzoic acid, where two of hydrazide compounds connected by four methylene chain were evaluated in series. Benzoylhydrazide type was found to be more effective on the enhancement of crystallization of poly( L ‐lactic acid). Effects of connecting length of methylene chain numbers between two of benzoylhydrazide on the nucleation ability were also evaluated. Benzoylhydrazide‐type compound having 10 methylenes, that is, decamethylenedicarboxylic dibenzoylhydrazide demonstrated excellent nucleation ability, and the resulted crystallization temperature and enthalpy of PLA with the compound of 1 wt % loading were 131°C and 46 J g −1 . The achieved crystallization temperature and enthalpy were over 10°C and over 10 J g −1 higher than PLA with conventional nucleating agents, such as talc and ethylenebis (12‐hydroxystearylamide). Thus, the improvement in processability, productivity, and heat resistance of PLA is suggested to be achieved by using decamethylenedicarboxylic dibenzoylhydrazide as a nucleating agent. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 198–203, 2007