作者：Jia Junping, Yang Jinjun (通讯作者), Zhao Yun, Liang Hui, Chen Minfang
关键字：Crystallization behavior, Mechanical property, PLLA
论文来源：期刊
具体来源：RSC Advances
发表时间：2016年

Nanocomposites of biodegradable PLLA and magnesium oxide composite (PLLA/MgO-NPs) and surface

modified magnesium oxide composite (PLLA/m-MgO-NPs) were prepared using a solution casting

method. Effects of the MgO-NPs and m-MgO-NPs on the crystallization behavior and mechanical

properties of the PLLA are investigated systematically. Differential scanning calorimetry (DSC) was used

to characterize the melting behavior and isothermal crystallization kinetics of pure PLLA and PLLA

nanocomposite samples at varying isothermal crystallization temperatures. The Avrami equation was

used to calculate the half crystallization time (t1/2) and shown that the m-MgO-NPs is a kind of better

nucleating agents than MgO-NPs because it enhanced crystallization rate significantly. Polarized optical

microscopy (POM) results showed the density of spherulites increased and their size decreased in PLLA/

MgO-NPs and PLLA/m-MgO-NPs samples. While the large amount (1.5 wt%) of MgO-NPs could hinder

the crystallization of the PLLA. a

0-PLLA emerged more easily than a-PLLA. The nucleation mechanism

and geometry of crystal growth of neat PLLA and PLLA nanocomposite materials were determined to be

similar. Mechanical property analysis showed both MgO-NPs and m-MgO-NPs could improve greatly the

tensile strength, Young''''s modulus and elongation at break. Especially in the case of PLLA/m-MgO-NPs,

the elongation at break was increased by 8.2 times. Uniform dispersion of m-MgO-NPs, and strong

interaction and binding force between m-MgO-NPs and the PLLA matrix are favorable for the large

enhancement in mechanical properties of the PLLA.