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Poly( l ‐lactic acid) with the organic nucleating agent N,N,N ′‐tris(1 H ‐benzotriazole) trimesinic acid acethydrazide: Crystallization and melting behavior
Author(s) -
Cai YanHua,
Tang Ying,
Zhao LiSha
Publication year - 2015
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.42402
Subject(s) - crystallization , materials science , differential scanning calorimetry , benzotriazole , melting point , nucleation , crystallinity , thermogravimetric analysis , glass transition , thermal decomposition , chemical engineering , polymer chemistry , nuclear chemistry , chemistry , organic chemistry , composite material , polymer , thermodynamics , physics , engineering , metallurgy
N,N,N ′‐Tris(1H‐benzotriazole) trimesinic acid acethydrazide (BD) was synthesized from 1H‐benzotriazole acetohydrazide and trischloride to serve as an organic nucleating agent for the crystallization of poly( l ‐lactic acid) (PLLA). First, the thermogravimetric analysis of BD exhibited a high thermal decomposition temperature; this indicated that BD maybe used as a heterogeneous nucleating agent of PLLA. Then, the effect of BD on the crystallization and melting behavior of PLLA was investigated through differential scanning calorimetry, depolarized light intensity measurements, and wide‐angle X‐ray diffraction. The appearance of a nonisothermal crystallization peak and increases in the glass‐transition temperature and the intensity of the diffraction peak suggested that the presence of BD accelerated the overall PLLA crystallization. Upon cooling at a rate of 1°C/min, the addition of just 0.5 wt % BD to PLLA increased the onset crystallization temperature from 101.4 to 111.3°C, and the nonisothermal crystallization enthalpy increased from 0.1 to 38.6 J/g. The isothermal crystallization behavior showed that the crystallization half‐time of PLLA with 0.5 wt % BD (PLLA/0.5% BD) decreased from 49.9 to 1.1 min at 105°C. However, the equilibrium melting point of PLLA/0.5% BD was lower than that of the pristine PLLA; this resulted from the increasing nucleating density of PLLA. The melting behavior of PLLA/0.5% BD further confirmed that BD improved the crystallization of PLLA, and the double‐melting peaks of PLLA/0.5% BD were assigned to melting–recrystallization. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42402.