【摘要】 本研究通过溶胶-凝胶法制备出纳米二氧化钛（TiO₂）,并采用硅烷偶联剂KH-550对其进行表面改性,减缓纳米TiO₂的团聚,通过溶液共混法制备出聚左旋乳酸（PLLA）/TiO₂复合薄膜。采用DSC、SEM、TG、紫外光谱和DMA等系统研究了TiO₂及其PLLA复合物的结构和性能。结果表明:TiO₂经过表面接枝改性后,平均粒径由533nm降低为346nm,其接枝率为4.2%（wt,质量分数,下同）。未改性的TiO₂在PLLA中分散性差,易团聚,改性后TiO₂在含量低于1.5%的条件下,能在PLLA中分散。TiO₂的加入提高了PLLA复合物的热稳定性、抗紫外性能和储能模量,对PLLA的结晶性能影响较小。更多还原

【Abstract】 Nano-TiO₂ with the average diameter of 533 nm was prepared by sol-gel method.The silane coupling agent KH550 was used to modify the TiO₂ surface by the grafting reaction.The resulting grafted TiO₂ was added to the poly（Llactic acid）（PLLA）matrix to prepare PLLA/TiO₂ nanocomposites via solution blending.The structure and properties of nano-TiO₂ and PLLA/TiO₂ nanocomposites were systematically investigated with the combination of differential scanning calorimeter（DSC）,X-ray scattering,scanning electron microscope（SEM）,thermo gravimetric analyzer（TG）,dynamic mechanical analyzer（DMA）and ultraviolet absorption spectra（UV）.The results showed that the grafting ratio of KH550 in TiO₂ was about 4.2wt% and the diameter of TiO₂-g-KH550 decreased.In the nanocomposites,grafted TiO₂ had a much lower degree of agglomeration than TiO₂ when the content was less than 1.5wt%.The nanoparticles played an important role in improving thermal stability,ultraviolet resistance and storage modulus of PLLA.The addition of TiO₂ had no obvious effect on the crystallization behavior of PLLA.更多还原