Zhu Chunxia, Pang Shuyu, Chen Zhaoxia, Bi Lehua, Wang Shuangfei, Liang Chen, Qin Chengrong
Guangxi Key Laboratory of Clean Pulp & Papermaking and Pollution Control, School of Light Industrial and Food Engineering, Guangxi University, Nanning 530004, China.
Xingjian College of Science and Liberal Arts, Guangxi University, Nanning 530004, China.
Polymers (Basel). 2022 Aug 2;14(15):3158. doi: 10.3390/polym14153158.
At present, the synthesis methods of crystalline porous materials often involve powder products, which not only affects the practical application but also has complex synthesis operations and limited scale. Based on the mechanochemical method, we choose COF-TpPa-1, preparing TpPa-1-DANC composites. Covalent organic frameworks (COFs) are a kind of crystalline material formed by covalent bonds of light elements. COFs possess well pore structure and high thermal stability. However, the state of synthesized powders limits their application. Cellulose nanocrystals (CNCs) are promising renewable micron materials with abundant hydroxyl groups on their surface. It is possible to prepare high-strength materials such as film, water, and aerogel. Firstly, the nanocellulose was oxidized by the sodium periodate method to obtain aldehyde cellulose nanocrystals (DANC). TpPa-1-DANC not only had the crystal characteristic peak of COFs at 2θ ≈ 5° but also had a BET surface area of 247 m/g. The chemical bonds between COFs and DANC formed by Schiff base reaction appeared in FTIR and XPS. The pyrolysis behavior of the composite was characterized by TG-IR, which showed that the composite had good thermal stability. With the advantages of nanocellulose as a material in every dimension, we believe that this method can be conducive to the large-scale synthesis of COFs composites, and has the possibility of multi-form synthesis of COFs.
目前，结晶多孔材料的合成方法通常涉及粉末产品，这不仅影响实际应用，而且合成操作复杂且规模有限。基于机械化学方法，我们选择COF-TpPa-1，制备TpPa-1-DANC复合材料。共价有机框架（COFs）是一种由轻元素共价键形成的晶体材料。COFs具有良好的孔结构和高热稳定性。然而，合成粉末的状态限制了它们的应用。纤维素纳米晶体（CNCs）是有前景的可再生微米材料，其表面有丰富的羟基。有可能制备薄膜、水凝胶和气凝胶等高强度材料。首先，通过高碘酸钠法氧化纳米纤维素，得到醛基纤维素纳米晶体（DANC）。TpPa-1-DANC不仅在2θ≈5°处有COFs的晶体特征峰，而且BET表面积为247 m/g。傅里叶变换红外光谱（FTIR）和X射线光电子能谱（XPS）显示了通过席夫碱反应在COFs和DANC之间形成的化学键。通过热重-红外联用（TG-IR）对复合材料的热解行为进行了表征，结果表明该复合材料具有良好的热稳定性。鉴于纳米纤维素作为材料在各个维度上的优势，我们认为这种方法有利于COFs复合材料的大规模合成，并且具有COFs多种形式合成的可能性。
