羧甲基化改性纳米甘薯渣纤维素的表征

Characterization of Carboxymethyl Modified Cellulose Nanocrystal from Sweet Potato Residue

以甘薯渣为原料,利用超声辅助酸法从薯渣中提取纳米纤维素,用羧甲基化对纳米纤维素进行亲水性改性,并对其理化性质进行表征。结果表明,羧甲基纳米纤维素仍为典型的球形粒子,粒径集中分布在30~50nm,与原纳米纤维素相比,表面结构更加疏松,化学反应活性增强;改性纳米纤维素的晶型结构发生了变化,结晶度明显降低,结晶指数由原来的73.27%下降到52.83%,但其热稳定性提高;改性纳米纤维素的实测纯度>99.5%,黏度<25 mPa·s,是一种高纯度极低黏度的纳米级羧甲基纤维素,可用做食品级添加剂。

With sweet potato residue as raw material,cellulose nanocrystals（CNCs） were achieved through ultrasonic-assisted acid method.Carboxymethyl cellulose nanocrystals（N-CMCs）were produced by carboxymethylation of CNCs.Transmission electron microscopy（TEM）showed that the N-CMCs were still typical spherical nano particles and slightly larger with a uniform diameter ranging from 30 nm to 50 nm.They were more loosely packed than the CNCs and had a porous surface structure.The crystallinity index of the N-CMCs（52.83%）was lower than that of CNCs（73.27%）,whereas the thermal stability of the former was higher.N-CMCs could be used as an excellent food additive,with low viscosity less than 25mPa·s,high purity more than 99.5% and nano-sized scale.