Table of Content

10 March 2022, Volume 43 Issue 3

Previous Issue    Next Issue

Content

Cover and Content of Chemical Journal of Chinese Universities Vol.43 No.3(2022)

2022, 43(3):  1. 

Asbtract ( )   PDF (11563KB) ( )  

Related Articles | Metrics

Review

Controlled Preparation of Carbon Nanotube Transparent Conductive Films

YAN Wenqing, ZHANG Zeyao, LI Yan

2022, 43(3):  20210626.  doi:10.7503/cjcu20210626

Asbtract ( )   HTML ( )   PDF (7833KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Carbon nanotubes have excellent electrical conductivity， light transmission properties， and outstanding flexibility， which gives them great application potential in flexible transparent conductive films. Preparation of carbon nanotube films with both good electrical conductivity and light transmission properties is the critical issue in this field. This review introduces the preparation methods of carbon nanotube films， and focuses on the controlled preparation of carbon nanotube films based on floating catalyst chemical vapor deposition. During the growth process， limi- ting the bundling of carbon nanotubes， increasing their length， and reducing the impurities are the main strategies to improve the performance of carbon nanotube films.



MOF-derived Carbon-based Electrocatalysts Confinement Catalyst on O₂ Reduction and CO₂ Reduction Reactions

ZHANG Xiaoyu, XUE Dongping, DU Yu, JIANG Su, WEI Yifan, YAN Wenfu, XIA Huicong, ZHANG Jianan

2022, 43(3):  20210689.  doi:10.7503/cjcu20210689

Asbtract ( )   HTML ( )   PDF (1211KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The massive consumption of fossil fuels and the gradual deterioration of the environment urgently require the development and exploration of effective energy conversion and storage technologies. Electrochemistry is the basis and key of all kinds of energy storage and conversion devices. The design and synthesis of non-noble metal-based and non metal-based catalysts with high catalytic activity are obviously the best choice. The metal organic framework （MOF） derived carbon-based materials have the characteristics of large specific surface area and high porosity， which can selectively confine metals of different types. Therefore， MOF has a good confinement effect when used as a catalyst， which is beneficial to improve the activity and stability of the catalyst. In this review， the confinement effects of MOF-derived materials in catalytic reactions are clarified， and the latest progresses of MOF-derived carbon-based materials in oxidation reduction reaction（ORR） and CO₂ reduction reaction（CO₂RR） electrocatalysis are introduced， and the structure-activity relationships of MOF-derived carbon-based materials in electrocatalytic reactions are revealed. Finally， the challenges and opportunities faced by MOF-confined carbon-based materials in ORR and CO₂RR electrocatalysis are discussed， as well as the possible solutions in the future.



Articles: Inorganic Chemistry

Design and Construction of UiO-66-NH₂/wood Composite for Efficient Removal of Trace Heavy Metal Ions from Water

LI Hua, YANG Ke, HUANG Junfeng, CHEN Fengjuan

2022, 43(3):  20210701.  doi:10.7503/cjcu20210701

Asbtract ( )   HTML ( )   PDF (5440KB) ( )  

Figures and Tables | References | Related Articles | Metrics

UiO-66-NH₂ Metal-Organic-Frameworks（MOFs） nanoparticles were in situ formed in the 3D low-tortuosity wood lumens by a facile solve-thermal strategy with ZrCl₄ and amino terephthalic acid as precursors. The UiO-66-NH₂/wood membrane showed excellent removal performance for removing heavy metal ions（Hg²⁺， Cu²⁺） in wastewater. The results showed that the removal efficiency for tested heavy metal ions（Hg²⁺， Cu²⁺） is more than 90.0% at the treatment rate of 1.0×10² L?m^-2?h^-1. Wood membrane， as a 3D substrate for anchoring UiO-66-NH₂ nanoparticles， contains numerous elongated and open lumens along the growth direction. On the one hand， it can enhance the water of including heavy metal ions fluxes； on the other hand， it can increase the contact probability of heavy metal ion containments with UiO-66-NH₂ MOFs as water flowing through the membrane. Therefore， the UiO-66-NH₂/wood membrane can efficiently remove trace heavy metal ions from the water. In addition， the UiO-66-NH₂/wood membrane also has good reusability， which is expected to be applied in practical applications.



Synthesis of Nano-zeolite and Its Adsorption Performance for Hydrogen Sulfide

MENG Xianglong, YANG Ge, GUO Hailing, LIU Chenguang, CHAI Yongming, WANG Chunzheng, GUO Yongmei

2022, 43(3):  20210687.  doi:10.7503/cjcu20210687

Asbtract ( )   HTML ( )   PDF (2695KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Nanosized SOD type and X-type zeolites were synthesized by the free-template hydrothermal method， and the hydrogen sulfide removal performance was investigated. By comparing the hydrogen sulfide adsorption performance of the two kinds of zeolite， it was confirmed that the adsorption of hydrogen sulfide in zeolite was mainly concentrated in the pores and accessible active sites. The influences of volume space velocity and adsorption temperature as well as the size of zeolite on hydrogen sulfide adsorption were deduced. It is found that nano-sized X zeolite has larger sulfur capacity， and the zeolite is easy to remove hydrogen sulfide molecules at low temperature and low space velocity. Then， the metal supported molecular sieves were obtained by ion exchange. The sulfur capacity of Cu-NaX-N can reach 20.6 mg/g， better than that of other ion modified adsorbents. The sulfur capacity of regenerated NaX-N and Cu-NaX-N zeolites can reach 62.4% and 78.5% of that of fresh zeolite， respectively.



Analytical Chemistry

Bis-naphthalimide Derivatives for Picronitric Acid Detection in Aqueous Solution

ZHAO Yongmei, MU Yeshu, HONG Chen, LUO Wen, TIAN Zhiyong

2022, 43(3):  20210765.  doi:10.7503/cjcu20210765

Asbtract ( )   HTML ( )   PDF (6361KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

A novel bis-naphthalimide derivative（Bis-Nph） was designed， synthesized and characterized by nuclear magnetic resonance spectroscopy（NMR） and high resolution mass spectrometry（HRMS）. Compound Bis-Nph presented typical intramolecular charge transfer（ICT） emission and aggregation-induced enhanced emission（AIEE）. It could be used as a fluorescent probe to detect 2，4，6-trinitrophenol（TNP） in aqueous solution， the calculated limit of detection is 5.8×10^-7 mol/L. The mechanism for sensing TNP was investigated using ¹H NMR. The proton transfers from TNP to Bis-Nph and blocks the ICT emission， and causes the fluorescence to be quenched remarkably. Further， Bis-Nph showed low cytotoxicity and could be made into test strips for rapid TNP detection.



Development and Validation of Multiple Physical Fields Coupling Model for Microwave-assisted Extraction

BI Gening, XIAO Xiaohua, LI Gongke

2022, 43(3):  20210739.  doi:10.7503/cjcu20210739

Asbtract ( )   HTML ( )   PDF (17749KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A multiple physical fields coupling model was developed using Comsol for microwave-assisted extraction（MAE） of alpinetin from Alpinia katsumadai Hayata， which was based on the coupling relations between the microwave field， temperature field and concentration field. And the model was used to simulate electromagnetic field distribution， temperature distribution and alpinetin diffusion distribution under different time and microwave powers. The model was verified by comparing the simulated and experimental values of extraction temperature and the concentration of alpinetin. Isoquercitrin in Amomum villosum， which belongs to the ginger family， was used as the target to further verify the applicability of the multiple physical fields coupling model. The results showed that the electromagne-tic field intensity was stronger， the temperature of the extraction solution was higher， and the diffusion of alpinetin was more obvious with the increase of microwave power， that was benefit to the extraction. The root relative mean square error（RRMSE） of extraction solution temperature between the simulated and experimental values for alpinetin and isoquercitrin was 1.9%—4.5% and 1.9%—2.8%， and concentration RRMSE was 1.7%—3.2% and 1.6%—4.1%， which were all less than 5.0%， indicating that the model was accurate and reliable. The model comprehensively considered multiple physical fields and the coupling relationships in the MAE process， which could provide a reference for further study of extraction mechanism.



Fabrication of Ag/Au Nanowires Array as a SERS Substrate for High-sensitivity Malachite Green Detection

XIA Dacheng, ZHOU Rui, TU Bo, CAI Zhiwei, GAO Nan, JI Xiaoxu, CHANG Gang, REN Xiaoming, HE Yunbin

2022, 43(3):  20210731.  doi:10.7503/cjcu20210731

Asbtract ( )   HTML ( )   PDF (11967KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In this work， Au nanowires（Au NWs） array was prepared through a seed-mediated soft template growth method， in which the morphology and structure of the Au NWs array can be controlled by adjusting the growth temperature. Silver nanoparticles（Ag NPs） were modified on the Au NWs array cleaned with sodium borohydride （NaBH₄） to prepare the silver/gold nanowires（Ag/Au NWs） array as the surface enhanced Raman scattering（SERS） substrate. The SERS performance of Ag/Au NWs array was investigated by testing rhodamine 6G（R6G）， a Raman probe molecule. The results indicate that Ag/Au NWs array as SERS substrate showed high sensitivity， excellent signal homogeneity and good stability. In the detection of malachite green in water， Ag/Au NWs array exhibited low detection limit of 1×10^-8 mol/L， and a wide linear range from 1×10^-8 mol/L to 1×10^-4 mol/L. In addition， NaBH₄ can remove adsorbed molecules on Ag/Au NWs array without affecting SERS performance， which allowing the SERS substrate to be recyclable. Reliable recovery rate obtained in real sample tests indicate that Ag/Au nanowires array has great potential in SERS detection of malachite green in environmental water.



Organic Chemistry

Preparation of Triphenylamine Based PAF-106s via Mechanical Ball Milling and C2 Hydrocarbons Adsorption Property

CHEN Xiaolu, YUAN Zhenyan, ZHONG Yingchun, REN Hao

2022, 43(3):  20210771.  doi:10.7503/cjcu20210771

Asbtract ( )   HTML ( )   PDF (2523KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Using triphenylamine as monomer， FeCl₃ as catalyst， and formaldehyde dimethyl acetal（FDA） as knitting agent， PAF-106s were prepared by mechanical ball milling different molar ratios of triphenylamine， FeCl₃ and FDA. Infrared spectroscopy， elemental analysis， X-ray photoelectron spectroscopy， and solid state nuclear magnetic field（NMR） proved that polymerization had taken place. N₂ adsorption results showed that the ratio of triphenylamine， FeCl₃ and FDA could affect the porous properties of PAF-106s. When the ratio of FeCl₃ to tripheny? lamine increased from 3∶1 to 12∶1， and the BET specific surface area of PAF-106c increased from 135 m²/g to 280 m²/g. With the introduction of FDA， the BET specific surface area of PAF-106d—PAF-106g decreased with the increase of the ratio of FeCl₃ and FDA. In addition， the adsorption and separation properties of C2 hydrocarbons for PAF-106c were investigated at 273 and 298 K， and the selectivities for C₂H₂/C₂H₄ and C₂H₆/C₂H₄ were calculated by ideal adsorbed solution theory（IAST）.



Fibroin Assisted Copper-promoted C-N Coupling Reaction

WU Fengtian, LI Jun, SUN Yijia, ZENG Rong, REN Han, LIU Xiuping, ZHANG Caihong, YAN Fangming, WU Ling, CUI Chunna

2022, 43(3):  20210707.  doi:10.7503/cjcu20210707

Asbtract ( )   HTML ( )   PDF (940KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

N-aryl derivative is an important motif prevalent in natural products and drugs. A fibroin assisted copper-promoted C-N coupling reaction using aryl halides and imidazole to afford the N-aryl compounds in excellent yields was reported. The reaction could be scaled up to multi-gram quantities and used to synthesize 2-phenylindole and 1，2，3-1H-triazole. The reaction mechanism was proposed based on the previous reports.



Moisture Absorption Reaction and Fluorescence Property of Highly Active Michael System Based on Arylidenemalononitrile

LI Qiao, ZHAO Yang, WANG Enju

2022, 43(3):  20210690.  doi:10.7503/cjcu20210690

Asbtract ( )   HTML ( )   PDF (3891KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

The phenols and alcohols as nucleophiles are common in oxa-Michael reaction， while H₂O normally cannot react with Michael system 2，2'-｛［5-（tert-butyl）-2-hydroxy-1，3-phenylene］bis（methaneylylidene）｝dimalononitrile（1） was reported， which could rapidly absorb water in the air to afford a stable 2-［5-（tert-butyl）-3-（2，2- dicyano-1-hydroxyethyl）-2-hydroxybenzyli-dene］malononitrile（2） via oxa-Michael addition. The high activity of compound 1 resulted from the synergistic effect among the two dicyanovinyl groups and the one hydroxyl group. In dimethyl sulfoxide（DMSO）， compound 2 could quickly dehydrate to give compound 1 in the presence of various alkaline catalysts. In PBS buffer（pH=10）， compound 2 immediately converted to compound 1， and then converted back to compound 2 slowly. When heat the silica gel plate loading compound 2， the fluorescence conversion from blue to red were observed. Hence， compound 2 adsorbed on silica gel might be developed into a thermosensitive fluorescent material. In addition， compound 2 adsorbed on silica gel showed fluorescence responses to some organic vapors.



Physical Chemistry

Revealing the Effect of Threonine on the Binding Ability of Antifreeze Proteins with Ice Crystals by Free-energy Calculations

CUI Shaoli, ZHANG Weijia, SHAO Xueguang, CAI Wensheng

2022, 43(3):  20210838.  doi:10.7503/cjcu20210838

Asbtract ( )   HTML ( )   PDF (4354KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The effect of the threonine content at the ice-binding site（IBS） of moderately active Lolium perenne antifreeze protein（LpAFP） on its binding ability to ice crystals was investigated， employing molecular dynamics simulations and free-energy calculations. A series of mutants of LpAFP were constructed by gradually increasing the amount of threonine on the IBS， including a mutation of eleven sites to make each β-strand have a Thr-x-Thr motif（x is a nonconserved amino acid， mostly a hydrophobic residue）. An importance-sampling algorithm， WTM-eABF， was used to explore the free-energy profile characterizing the adsorption process for LpAFP and its different mutants. WTM-eABF merges the key features of well-tempered metadynamics?“flooding valleys” and an extended Lagrangian variant of adaptive biasing force?“shaving barriers”（WTM-eABF）， which greatly improves the sampling efficiency of the algorithm. The free-energy calculation results indicate that the higher the threonine content of the IBS， the energetically more favorable for binding of AFPs to ice crystals. The mutant with a repeating sequence Thr-x-Thr motif on its flat β-sheet region has the strongest binding affinity to ice. Further analysis showed that the higher the content of threonine， the more ordered water molecules around the IBS， the longer the existence of the anchored clathrate water， and the more stable hydrogen bond network between the IBS and ice surface， thus improving the association strength of AFPs with ice. Overall， increasing the content of threonine residues could significantly enhance the binding ability to ice， which constitutes an approach to improve the antifreeze activity of antifreeze proteins with moderate activity.



The Second Order Nonlinear Optical Properties of Azulene-defect Graphene Nanosheets with Full Armchair Edge

ZHENG Xuelian, YANG Cuicui, TIAN Weiquan

2022, 43(3):  20210806.  doi:10.7503/cjcu20210806

Asbtract ( )   HTML ( )   PDF (4303KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Based on the graphene nanosheets（GNSs） with full armchair edge， the second order nonlinear optical properties of these GNSs in different shapes with good chemical stability were modulated by introducing two， three and four azulenes. The result shows that the number of azulene defects plays a dominant role in the second order nonlinear optical responses of these GNSs. The GNSs with four azulenes have large second order nonlinear optical responses， among which AP-4a has the largest static first hyperpolarizability（<β₀>， 230387.70 a. u.， 2260.42 a. u. per heavy atom）. In addition， the nanosheet shape also has a certain effect. The azulene moieties not only induce charge distribution polarization of GNSs， but also dominate in the major electron transitions with important contribution to the nonlinear optical responses. Azulene as a functional unit of carbon-based nanomaterials significantly improves the photoelectric properties of carbon-based nanomaterials， and this finding provides practical strategies and useful information for future carbon-based nonlinear optical materials design.



Preparation of Supported Pd-Cu Catalyst and Its Preferential Oxidation of CO Under Hydrogen-rich Atmosphere

ZHAO Wanjun, LI Xiao, Dang Hui, WANG Yongzhao, ZHAO Yongxiang

2022, 43(3):  20210754.  doi:10.7503/cjcu20210754

Asbtract ( )   HTML ( )   PDF (2883KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Three supported Pd-Cu catalysts（PC-Al₂O₃， PC-SiO₂， PC-C₃N₄） were prepared by a simple impregnation method using Al₂O₃， SiO₂， and C₃N₄ as supports. And their catalytic performance toward CO preferential oxidation at room temperature were investigated. XRD， FTIR， N₂-physisorption， H₂-TPR， CO₂-TPD， XPS and in situ DRIFTS were used for analysis and characterization. The results show that compared with PC-SiO₂ and PC-C₃N₄， PC-Al₂O₃ shows better CO preferential oxidation performance， which is due to the formation of a large number of Cu₂Cl（OH）₃ species with strong interaction with Pd species on PC-Al₂O₃. However， PC-SiO₂ exists only a small amount of Cu₂Cl（OH）₃ and its weaker interaction with Pd species. In addition， Cu species in PC-C₃N₄ is more likely to coordinate with C₃N₄ matrix， which weakens the interaction between Pd and Cu. Above all， Pd⁺ species with stronger CO activation ability readily emerge on the surface of PC-Al₂O₃ in the reaction atmosphere， which possess the close interaction with a large number of Cu⁺ species. And this can inhibit the complete reduction of Pd⁺ to Pd⁰ to a certain extent， so as to maintain its catalytic activity. Hence， compared with SiO₂ and C₃N₄， Al₂O₃ is more suitable for supporting Pd-Cu for CO preferential oxidation in hydrogen.



Molecular Simulation of the Osmotic Pressures for LiCl-NaCl-KCl-H₂O Solution System

CHEN Hanxiang, BIAN Shaoju, HU Bin, LI Wu

2022, 43(3):  20210727.  doi:10.7503/cjcu20210727

Asbtract ( )   HTML ( )   PDF (1911KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Salt Lake Brines contain large amount of lithium and potassium resources. Developing models and methods that predicts the osmotic pressures of brines shows significance in utilizing salt lake resources. Molecular dynamics（MD） technology equipped with osmotic pressure in aqueous solutions（OPAS） method were applied to study the prediction of osmotic pressures of LiCl-NaCl-KCl-H₂O solution system. The computed results were compared with experimental and Pitzer model calculated data， and the data includes osmotic pressures of solutions of the same type and different concentrations and of the same concentration and different types. The results show that this approach is capable to calculated the osmotic pressures quantitively and semi-qualitatively for complex mixture systems.



Photothermal Enhanced Photocatalytic Hydrogenation Performance of Au/RGO/Na₂Ti₃O₇

MENG Xiangyu, ZHAN Qi, WU Yanan, MA Xiaoshuang, JIANG Jingyi, SUN Yueming, DAI Yunqian

2022, 43(3):  20210655.  doi:10.7503/cjcu20210655

Asbtract ( )   HTML ( )   PDF (5378KB) ( )  

Figures and Tables | References | Supplementary Material | Related Articles | Metrics

Typical photothermal plasmon graphene and nano gold were simply supported on sodium titanate（Na₂Ti₃O₇）. Thus， Au/RGO/Na₂Ti₃O₇ photothermal-assisted photocatalytic system was constructed， featured with narrow bandgap and high photocatalytic activity. Graphene sheets and gold nanoparticles could generate a large number of hot-electron for activating reactants and reducing the reaction energy，through their local surface plasmon resonance effect under light. The photothermal effect can precisely raise the temperature near the reaction site， thus greatly improving the photocatalytic reaction rate. In addition， the Au/RGO/Na₂Ti₃O₇ catalyst is endow with enhanced light-trapping performance by ably constructing special micro-branched structure. Also， the stability of catalyst was enhanced by confinement effects. Under the synergistic enhancement of photothermal effect and photocatalysis， Au/RGO/Na₂Ti₃O₇ catalyst showed enhanced photocatalytic activity for the p-nitrophenol hydrogenation and cin-namaldehyde hydrogenation. The turnover frequency（TOF） of the p-nitrophenol reduction reaction catalyzed by the photothermal-assisted Au/RGO/Na₂Ti₃O₇ was up to 54.4 min^-1， and the activation energy barrier was significantly reduced to 15.78 kJ/mol. Moreover， it showed high stability in the long-term test（after 4 cycling test， the conversion retention rate was nearly 90%）.



Fabrication of Lithium-sulfur Battery Cathode with Radiation Crosslinked Low Molecular Weight of Polyacrylonitrile and the Mechanism of Sulfur Storage

ZHANG Shiyu, HE Runhe, LI Yongbing, WEI Shijun, ZHANG Xingxiang

2022, 43(3):  20210632.  doi:10.7503/cjcu20210632

Asbtract ( )   HTML ( )   PDF (10865KB) ( )  

Figures and Tables | References | Related Articles | Metrics

By the method of γ-ray irradiation cross-linking heteromorphic polyacrylonitrile（PAN）fibers， the pro? blem of melt collapse in the semi-carbonization of low-molecular-weight polyacrylonitrile was solved and the semi- carbonization stability of PAN was impoved. The irradiation cross-linking mechanism was first determined by Fourier transform infrared spectra， elemental analysis and nuclear magnetic resonance spectra. At the same time， according to the relationship between the different degree of crosslinking produced by irradiation and the change of sulfur load after PAN vulcanization， the sulfur storage mechanism of vulcanized polyacrylonitrile（SPAN） for lithium-sulfur battery cathode material was discussed. Using Raman spectra， X-ray photoelectron spectra and other analytical methods， from the perspective of cross-linking， the reaction position of S in SPAN was demonstrated， and the tertiary carbon on the PAN main chain was the active site for chemical bonding with S. It provides a new basis for exploring the SPAN structure. The increase in the degree of cross-linking promotes the electrochemical stability of the SPAN cathode material formed after vulcanization， and the capacity retention rate can be increased to 98%.



Polymer Chemistry

Preparation of Transparent Antistatic Multifunctional Superhydrophobic Film

WANG Ruijie, JIAO Xiaoyu, PAN Yu, WANG Xunchun, YANG Yang, CHENG Zhongjun

2022, 43(3):  20210703.  doi:10.7503/cjcu20210703

Asbtract ( )   HTML ( )   PDF (4706KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Silver nanowires and hydrophobic nano-silica were coated on the surface of polyimide film by a simple pulling method. During the process， the conductive network and superhydrophobic coating were constructed respectively. The results show that the static contact angle of water droplets on the surface of the film is as high as 156.4°， and the rolling angle is less than 1°， indicating that the film has excellent superhydrophobic characteristics. At the same time， the film maintains high light transmittance， and its light transmittance is higher than 90%. The construction of silver nanowire network effectively increases the conductivity of the film， making the surface resistance of the film between 10⁶—10¹⁰ Ω， meeting the anti-static requirements. In short， through the construction of conductive network and hydrophobic coating， the unity of transparent， antistatic and superhydrophobic functions is realized.



Preparation of DOPO Derivative Modified Carbon Nanotubes and Their Effect on Flame Retardancy of Polylactic Acid

GAO Jing, HE Wentao, WANG Xinxin, XIANG Yushu, LONG Lijuan, QIN Shuhao

2022, 43(3):  20210670.  doi:10.7503/cjcu20210670

Asbtract ( )   HTML ( )   PDF (9508KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Using carboxyl carbon nanotubes（CNT-COOH）and 9，10-dihydro-9-oxa-10-phosphaphenanthrene-10- oxide（DOPO） derivative DOPO-NH₂ as raw materials， a new type of inorganic-organic hybrid flame retardant（CNT-DOPO） was prepared through acid chlorination and condensation reactions. The structure was characterized by Fourier transform infrared spectroscopy， transmission electron microscopy， X-ray photoelectron spectroscopy and thermogravimetric analysis， and the grafting rate was quantitatively tested. CNT-COOH， DOPO-NH₂ and CNT-DOPO were added to polylactic acid（PLA） in the same mass fraction of 5% to prepare flame-retardant PLA composites. The results showed that DOPO-NH₂ was successfully grafted onto carbon nanotubes with a grafting rate of about 50%. The cone calorimetric test results showed that the peak heat release rate of PLA/5CNT-COOH， PLA/5DOPO-NH₂ and PLA/5CNT-DOPO was 46%， 3.4%， 39.8% lower than that of pure PLA， respectively. The morphology and structure analysis of the char residues showed that the char layer of PLA/5CNT-DOPO had the highest degree of graphitization， and carbon nanotubes and DOPO-NH₂ had a certain promoting effect on the condensed phase flame retardancy. The rheological results showed that the addition of carbon nanotube had a great effect on the viscoelastic transition of PLA composites. PLA/5CNT-COOH and PLA/5CNT-DOPO basically exhibited elastic behavior. The addition of carbon nanotube or modified carbon nanotube increased the viscosity of PLA composites at low frequency， and promoted the formation of consistent and compact char layer in the later stage of combustion， Accordingly， the heat release rate and the smoke production of PLA composites decreased significantly.