The crystallization behaviors and mechanical properties of poly(L-lactide)/magnesium oxide nanoparticle composites
作者：Jia Junping, Yang Jinjun (通訊作者), Zhao Yun, Liang Hui, Chen Minfang
關(guān)鍵字：Crystallization behavior, Mechanical property, PLLA
論文來源：期刊
具體來源：RSC Advances
發(fā)表時間：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.