A newly synthesized aromatic sulfonate compound,complex 2 with formula of K2[H3COOC-C6H3(SO3)2]·2H2O(methyl 3,5-disulfo-benzoate dipotassium dihydrate) was synthesized and characterized by elemental analysis,infrared(IR) spectrometry,nuclear magnetic resonance(NMR) and crystal structure measurement.Single-crystal X-ray diffraction(XRD) revealed that complex 2 crystallized in the triclinic system with space group P(i).Complex 2 was used as nucleating agent for poly(L-lactide)(PLLA).The crystallization of PLLA with powder of complex 2 was investigated by means of differential scanning calorimetry(DSC) and polarized optical microscopy (POM).The results prove that complex 2 was effective as nucleating agent for PLLA.It could accelerate crystallization by reducing the induction time and increasing the density of nuclei in the crystallization process.The half-time of crystallization(t0.5) for pure PLLA was about 8 times longer than that of PLLA sample with 1.0%(mass fraction) of complex 2.
SUN Zhiqiang ZHANG Han PANG Xuan BIAN Xinchao CHEN Wenqi CHEN Xuesi
A series of Schiff base aluminum(III) complexes bearing morpholinomethyl substituents were synthesized. Comprehensive investigations on their stereoselective and kinetic features in the ring opening polymerization of lactide were carried out. The ring opening polymerization proved to be first-order in the catalyst and the monomer. Linear relationships between the numberaverage molecular weight of the polylactide and the monomer conversion were consistent with a well-controlled polymerization. The propagation rate was strongly affected by morpholinomethyl substituents on the salicylaldehyde moiety.