摘要
采用硫酸水解法制备纤维素纳米晶(CNC),并对CNC进行乙酰化改性(A-CNC)、TEMPO氧化(T-CNC)、阳离子疏水改性(C-CNC)、阳离子亲水改性(E-CNC)、烷基化改性(S-CNC)、聚丙烯酸接枝改性(P-CNC),之后采用红外光谱、固态碳谱、X射线衍射分析、透射电镜、原子力显微镜、热重分析、分散性分析等表征方法研究了不同改性方法对CNC晶体结构及性能的影响。结果表明,这些改性不会对CNC晶体结构产生严重影响,依然保持棒状结构和纳米尺寸;改性后的纤维素纳米晶结晶度有不同程度的下降,其中A-CNC下降最大,达21.2%;改性后的纤维素纳米晶基本在250~350℃发生降解,而未改性的在200℃就已开始降解;不同的改性可以改变CNC在不同溶剂中的分散性,阳离子亲水改性可以显著提高纤维素纳米晶的热稳定性。
Using sulfuric acid hydrolysis of cellulose nanocrystals(CNC),and acetylated modification was carried out on CNC(A-CNC),TEMPO oxidation(T-CNC),cationic hydrophobic modification(C-CNC),cationic hydrophilic modification(E-CNC),alkylated modification(S-CNC),poly acrylic acid grafted modification(P-CNC).The effects of different modification methods on the crystal structure of CNC were studied by infrared spectroscopy,solid-state carbon spectrum,X-ray diffraction analysis,transmission electron microscopy,atomic force microscopy,thermogravimetric and redispersion analysis and other characterization methods.The results show that these modifications do not have serious effects on the crystal structure of CNC,and the rod structure and nanometer sizes are still maintained.The crystallinity of the modified cellulose nanocrystals is decreased with different degrees,of which A-CNC is decreased the most,up to 21.2%.The degradation of modified cellulose nanocrystals is basically at 250~350℃,while the degradation of unmodified cellulose nanocrystals starts at 200℃.Different modifications can change the dispersion of CNC in different solvents.The cationic hydrophilic modification can significantly improve the thermal stability of cellulose nanocrystals.
作者
徐峻
高艺
吴祺祺
王佳佳
李军
王斌
Jun Xu;Yi Gao;Qiqi Wu;Jiajia Wang;Jun Li;Bin Wang(State Key Laboratory of Pulp and Paprr Engineering,South China University of Technology,Guangzhou 510640,China;Tianjin Key Laboratory o f Pulping and Papermaking,Tianjin University of Science and Technology,Tianjin 300457,China)
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2021年第3期66-71,78,共7页
Polymer Materials Science & Engineering
基金
国家重点研发计划(2017YFB0307902)
国家科技重大专项(2017ZX07402004)
天津市制浆造纸重点室开放基金(201803)。
关键词
纤维素纳米晶
改性
结晶结构
热稳定性
cellulose nanocrystals
modification
crystalline structure
thermal stability
