花生壳纳米纤维素的制备与表征

Preparation and Characterization of Cellulose Nanocrystals from Peanut Shells

本文以花生壳为原料,在氢氧化钠碱解和亚氯酸钠漂白预处理基础上,通过硫酸水解方法制备花生壳纳米纤维素。采用扫描电镜、透射电镜、红外光谱、X-射线衍射和热失重分析对花生壳纳米纤维素的表征进行研究。结果表明,通过碱解和漂白处理,花生壳半纤维素和木质素被大量去除,花生壳纤维素含量由43.84%增加到86.56%,纤维素直径为10-30μm;花生壳纳米纤维素呈棒状结构,长度为90-210nm,直径为5-25nm;花生壳纳米纤维素制备过程中纤维素结构并未遭到破坏;结晶度随制备过程逐渐增高,花生壳纳米纤维素结晶度为74.71%,呈典型的纤维素I型晶型;花生壳纳米纤维素的起始热分解温度较低,当温度达到500℃时,花生壳纳米纤维素的残余率大于30%。所制备的花生壳纳米纤维素有望在可降解复合材料中得到应用。

In this study, cellulose nanocrystals were prepared from peanut shells via pretreatments including alkalihydrolysis with sodiumhydroxide, bleaching with sodium chlorite, and sulfuric acidhydrolysis. The obtained cellulose nanocrystals were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. The results showed that extensive amounts ofhemicellulose and lignin from peanut shells were removed by alkalihydrolysis and bleaching, so that the content of cellulose increased from 43.84% to 86.56% and the molecular diameter of cellulose was between 10 and 30μm.The nanocrystals were rod-shaped, between 90 and 210 nm long, with a diameter ranging from 5 to 25nm. The molecular cellulose type I crystalline structure remained intact while the crystallinity gradually increased to 74.71% during the preparation of cellulose nanocrystals. The initial decomposition temperature of cellulose nanocrystals was low, when the temperature reached 500°C, the residue weight of cellulose nanocrystals was more than 30%. The cellulose nanocrystals prepared from peanut shellshave potential application in biodegradable composites.