Exponentially increased nucleation ability for poly(L-lactide) by adding acid-oxidized multiwalled carbon nanotubes with reduced aspect ratios  

作　　者：ZHONG Yong ZHANG YaQiong YANG JingJing LI WenLin WANG ZhiGang XU DongHua CHEN ShouYu DING YunSheng 

机构地区：[1]CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China [2]State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences [3]Institute of Polymer Materials & Chemical Engineering, School of Chemical Engineering, Hefei University of Technology [4]Anhui Key Laboratory of Controllable Chemistry Reaction & Material Chemical Engineering

出　　处：《Science China Chemistry》2013年第2期181-194,共14页中国科学（化学英文版）

基　　金：financially supported by the National Natural Science Foundation of China (51073145);National Basic Research Program of China (2012CB025901);partially by the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences

摘　　要：Acid-oxidized multiwalled carbon nanotubes (A-MWCNTs) with a range of reduced aspect ratios (from about 11 to 5.8) were obtained by acid oxidization of MWCNTs in the mixture of HNO 3 and H 2 SO 4 for varying periods of 1, 3, 8 and 12 h, respec- tively. The aspect ratios and surface functionalization of A-MWCNTs were well characterized by scanning electron microsco- py (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA). Poly(L-lactide)/A-MWCNT composites containing 0.5 wt% A-MWCNTs with a range of reduced aspect ratios were prepared by solution cast. The effects of added A-MWCNTs on the isothermal crystallization kinetics of poly(L-lactide)/A-MWCNT composites were investigated by means of differential scanning calorimetry (DSC), rheology and polarized optical microscopy (POM). It is surprising to find that not only the addition of A-MWCNTs effectively increases the poly(L-lactide) (PLA) crys- tallization kinetics, but also the nucleation ability of A-MWCNTs for PLA crystallization exponentially increases with the re- duced aspect ratio, that is to say, those with lower aspect ratios show much stronger nucleation ability for PLA crystallization than those with higher aspect ratios. The exponentially increased nucleation ability of A-MWCNTs with a range of reduced aspect ratios for PLA crystallization is disclosed.Acid-oxidized multiwalled carbon nanotubes （A-MWCNTs） with a range of reduced aspect ratios （from about 11 to 5.8） were obtained by acid oxidization of MWCNTs in the mixture of HNO 3 and H 2 SO 4 for varying periods of 1, 3, 8 and 12 h, respec- tively. The aspect ratios and surface functionalization of A-MWCNTs were well characterized by scanning electron microsco- py （SEM）, Fourier transform infrared spectroscopy （FTIR）, Raman spectroscopy and thermogravimetric analysis （TGA）. Poly（L-lactide）/A-MWCNT composites containing 0.5 wt% A-MWCNTs with a range of reduced aspect ratios were prepared by solution cast. The effects of added A-MWCNTs on the isothermal crystallization kinetics of poly（L-lactide）/A-MWCNT composites were investigated by means of differential scanning calorimetry （DSC）, rheology and polarized optical microscopy （POM）. It is surprising to find that not only the addition of A-MWCNTs effectively increases the poly（L-lactide） （PLA） crys- tallization kinetics, but also the nucleation ability of A-MWCNTs for PLA crystallization exponentially increases with the re- duced aspect ratio, that is to say, those with lower aspect ratios show much stronger nucleation ability for PLA crystallization than those with higher aspect ratios. The exponentially increased nucleation ability of A-MWCNTs with a range of reduced aspect ratios for PLA crystallization is disclosed.

关 键 词：poly（L-lactide） MWCNTs aspect ratio NUCLEATION 

分 类 号：O631.3[理学—高分子化学] TB383.1[理学—化学]