Unbleached cellulose obtained from corncobs were used to synthesize cellulose nanocrystals (CNC). Corncobs are an agro-industrial residue has a high cellulose content and can be used as a raw material to obtain CNC. The cellulose was extracted from the corncobs by means of delignification in two stages, the first stage consisted of a pulping process with ethanol and acetic acid (organosolv method) and in the second stage, the corncob was treated with an organosolv method and potassium hydroxide, followed by sodium hydroxide and boric acid (extraction and purification) to eliminate hemicellulose. The obtained cellulose was not bleached, in order to maintain the groups corresponding to lignin and hemicellulose on their surface. Afterward, the obtained cellulose underwent acid hydrolysis to obtain CNC, using sulphuric acid at 64%. These nanocrystals were characterized by x-ray diffraction, atomic force microscopy, thermogravimetric analysis and zeta potential. The CNC obtained from the two types of unbleached cellulose showed have sizes from 125.18 to 225.86 nm in length and 11.61 to 35.92 nm in diameter. The results indicate not only that CNC can be obtained from unbleached cellulose corncob, but also that their characteristics are similar from those obtained by means of bleached cellulose.

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废玉米芯中未漂白的纤维素用于分离纤维素纳米晶体

从玉米芯获得的未漂白纤维素用于合成纤维素纳米晶体（CNC）。玉米芯是一种纤维素含量高的农残产品，可以用作获得CNC的原料。通过去木质素从玉米芯中分两步提取纤维素，第一阶段包括用乙醇和乙酸制浆（有机溶剂法）；第二阶段，玉米芯用有机溶剂法和氢氧化钾处理，然后用氢氧化钠和硼酸（萃取和纯化）除去半纤维素。为了保持与木质素和半纤维素相对应的基团在其表面上，不对所得纤维素进行漂白。之后，使用64％的硫酸对所得纤维素进行酸水解以得到CNC。这些纳米晶体通过X射线衍射，原子力显微镜，热重分析和Zeta电位进行表征。由两种类型的未漂白纤维素制得的CNC分子筛的长度为125.18至225.86 nm，直径为11.61至35.92 nm。结果表明，不仅可以从未漂白的纤维素玉米芯获得CNC，而且它们的特性与通过漂白纤维素获得的那些相似。