Synthesis of N, N′-bis(benzoyl) azelaic acid dihydrazide and its Effect on Performance of Poly (L-lactic acid)

In order to synthesize more function amides, N, N'-bis(benzoyl) azelaic acid dihydrazide(NA(A)) was synthesized from benzoyl hydrazine and azelaoyl chloride which was deprived from azelaic acid via acylation. The influence of the reaction ratio, reaction time and reaction temperature to the yield of NA(A) was investigated by orthogonal experiment, the optimization result was: molar ratio of benzoyl hydrazine: azelaoyl chloride 2:3, reaction time 6 h, reaction temperature 70 degrees C. The yield was 89.7%. Non-isothermal crystallization behavior measure indicated that NA(A) showed excellent nucleating effects on Poly(L-lactic acid)(PLLA) crystallization. Compared to the neat PLLA, with the addition of 0.8% NA(A), the crystallization temperature increased from 105.88 degrees C to 122.99 degrees C,the degree of supercooling decreased from 55.33 degrees C to 36.96 degrees C while the crystallization enthalpy increased from 1.379 J.g(-1) to 28.58 J.g(-1) at a cooling rate of 1 degrees C/min from melt. The tensile strengths and tensile modulus increased with the increasing of NA(A) contents and possessed a maximum value for the critical NA(A) loading 0.3% and 0.5%, respectively. However, the elongations at break of PLLA/NA(A) samples decreased significantly. The hardness of PLLA/NA(A) samples after isothermal crystallization increased, and the largest value of hardness of PLLA/NA(A) with 1% NA(A) after isothermal crystallization was 176N/mm(2).