PLA/R-TiO2复合材料的紫外光老化行为

Study on the Ultraviolet Aging Behavior of PLA/TiO2 Composites

为研究聚乳酸/金红石型二氧化钛(PLA/R-TiO2)复合材料抗紫外老化行为,揭示R-TiO2散射紫外光线的抗老化机理,采用熔融共混法制备PLA/R-TiO2复合材料,通过差示扫描量热(DSC)分析、X射线衍射(XRD)、全反射红外光谱(ATR-FTIR)、力学性能测试,以及扫描电镜(SEM)观察等方法,研究PLA经紫外光辐照前后的结构性能变化以及R-TiO2在改善PLA抗紫外光性能方面的作用。结果表明:R-TiO2的引入可促进PLA结晶,结晶度由12.11%增加到25.91%;随老化时间延长,PLA拉伸强度下降了94.5%,色差值增加到4.13,表面出现裂纹和孔洞结构;随R-TiO2用量增加,拉伸强度下降幅度明显降低,色差值减小,其中R-TiO2添加量为3wt%时可有效改善PLA的紫外稳定性。

To study poly(lactic acid)(PLA)/rutile type titanium dioxide(PLA/R-TiO 2)composite anti ultraviolet aging behavior,and reveal the R-TiO 2 scattering the anti-aging mechanism of ultraviolet light,PLA/R-TiO 2 composites were prepared by melt blending method.By means of differential scanning calorimetry(DSC),X-ray diffraction(XRD),total reflection infrared spectroscopy(ATR-FTIR),mechanical properties test and scanning electron microscopy(SEM),the changes of structure and properties of PLA irradiated by ultraviolet light and the role of R-TiO 2 in improving the ultraviolet resistance of PLA were studied.The changes of surface functional groups of PLA were tested to clarify the changes of structure and properties of PLA.The anti-aging mechanism of R-titanium dioxide scattering ultraviolet light was revealed.Introduction of R-TiO 2 could promote PLA crystallization from 12.11%to 25.91%.With the extension of aging time,the tensile strength of PLA has fallen by 94.5%,and the color difference value increased to 4.13.As result,the surface structures appeared cracks and holes phenomenon.With the R-TiO 2 dosage increased,compared with PLA,the decrease trend of tensile strength after ultraviolet aging became significantly slower,and the color difference value decreased.When the R-TiO 2 added to 3wt%,the UV stability of PLA could be effectively improved.