Indexed by:期刊论文

Date of Publication:2019-09-01

Journal:EUROPEAN POLYMER JOURNAL

Included Journals:SCIE、EI

Volume:118

Page Number:337-346

ISSN No.:0014-3057

Key Words:Poly(L-lactic acid); Zinc salts of amino acids; Nucleating agents

Abstract:The slow crystallization speed of poly(L-lactide) (PLLA) during practical processing results in the low degree of crystallinity and thus poor heat resistance of the molded articles, which prevents the wider applications of PLLA. The additive of biocompatible nucleating agents is one of the most effective means to promote the crystallization of PLLA, which synchronously preserves the bio-advantages of PLLA materials for biomedical and food applications. In this work, a series of zinc salts of amino acids, including nine kinds of L-amino acids and six types of D- or DL-configuration amino acids, was prepared and evaluated as nucleating agents (NM) for PLLA. The nucleation effect of NAs was compared in terms of the nonisothermal melt crystallization peak temperature of PLLA with 1 wt% loading of NM under a cooling rate of 10 degrees C/min. It was found that the nucleation effect of the zinc salts of amino acids depends on the ligand and its configuration. The nucleation mechanism and the difference of nucleation ability were also discussed and explained. Among these tested NAs, zinc o-phenylalaninate (Zn(D-Phe)(2) is the most effective one, which is comparable to the current outstanding NM, evidenced by the crystallization peak temperature at 130 degrees C accompanying with the crystallization enthalpy up to 48 J/g. It is expected that Zn(D-Phe)(2) is a promising nucleating agent providing high nucleation activity in injection molding and extrusion processing of PLLA articles.