聚乳酸/可分散性纳米二氧化硅复合材料等温结晶行为研究

Isothermal crystallization behavior of PLA/dispersible nano-SiO_2 composites

采用超声辅助、熔融共混的方法,用可分散的纳米二氧化硅颗粒(DNS)对聚乳酸(PLA)进行改性处理,利用差示扫描量热法(DSC)、X射线粉末衍射分析(XRD)、FTIR等测试手段研究了DNS对PLA等温熔融结晶和等温冷结晶行为的影响,并且对测得数据用Avarmi方程进行处理,研究其等温结晶动力学.结果表明:DNS使PLA的等温熔融结晶和等温冷结晶的半结晶时间t_(1/2)减小、结晶速率提高,Avarmi指数n变化不大,说明DNS没有改变PLA结晶的成核机理.

Poly(L-lacticacid)(denoted as PLA)was modified used dispersible nano-Si02(DNS)by melting blending and ultrasound-assisted.Differential scanning calorimetry(DSC),X-ray powder diffractometer(XRD)and FTIR methods were used to study the effect of the dispersion of DNS on the isothermal melt crystallization and isothermal cold crystallization behavior of PLA,and the Avarmi equation was also used to deal with the measured data to study the isothermal crystallization kinetics.DNS is a kind of heterogeneous nuclei.By adding DNS to PLA,the isothermal melting crystallization and the isothermal cold crystallization rate of PLA resin were improved obviously,and with the increase of DNS content,the crystallization rate of DNS was increased,the half-crystallization time tl/2decreased,and the Avarmi index n slightly changed.It indicated that DNS did not change the nucleation mechanism of crystal process of PLA.