两种方法制备羧基化纳米纤维素及其性能

Preparation of the Carboxylated Cellulose Nanocrystals by Two Different Methods

以棉纤维为原料,通过两种不同的方式制取:硫酸水解-TEMPO氧化两步法以及过硫酸铵一步氧化法制备出两种羧基化纤维素纳米晶体(Carboxylated cellulose nanocrystals,CCNs)。采用原子力显微镜(AFM)、扫描电镜(SEM)、纳米颗粒分析仪、傅里叶红外光谱(FT-IR)、X-射线衍射(XRD)、热重分析(TGA)及电导滴定法等手段对纳米纤维素的形态结构、结晶性能、化学结构、热稳定性及羧基含量进行了表征。结果表明,两种方式均制备出棒状的羧基化纳米纤维素晶体,均具备原纤维的基本化学结构和晶体结构,但所得的纳米粒子的尺寸及氧化度存在较大差异,结晶度与热稳定性的下降程度也有所不同。本对比研究可为羧基化纳米纤维素晶体的制备及应用提供一定的参考及试验依据。

Carboxylated cellulose nanocrystals （CCNs） were prepared from cotton pulp by two different methods, i. e., TEMPO-mediated oxidation of cellulose nanocrystals （CNCs） and ammonium persulfate oxidation of cotton pulp. The morphological structure, particle size, crystallinity, chemical structure, thermal stability, and the carboxyl content of CCNs were characterized by AFM, SEM, Nano Particle Analyzer, XRD, FT-IR,TGA and conductimetry. The results showed that the rodlike CCNs with different particle sizes and different oxidation degree were successfully prepared by the two different methods, which own the same chemical and crystalline structure of cellulose compared with origin pulp, and their crystallinity and thermal stability decreased at different levels. This comparative study can provide the basis for the preparation and application of CCNs.