双醛纳米晶纤维素的制备及其表征

Preparation and Characterization of Dialdehyde Nano-crystalline Cellulose

阔叶木溶解浆经酸水解制备纳米晶纤维素(NCC),采用高碘酸钠法对NCC进行氧化制备双醛NCC,探讨了高碘酸钠使用量、p H、反应温度和反应时间对双醛NCC醛基含量的影响.结果表明,适宜的氧化反应条件为:高碘酸钠与NCC质量比为2、p H 3、反应温度40,℃、反应时间4,h,此时双醛NCC醛基含量为73%,.FTIR、XRD、AFM和聚合度检测表明:双醛NCC已经生成;溶解浆纤维素水解成NCC后的结晶度以及NCC氧化成双醛NCC后的结晶度都发生了变化;NCC呈梭形棒状结构,NCC氧化后粒径变小;聚合度在纤维素水解成NCC后大幅降低,经过高碘酸钠氧化,聚合度进一步下降.

Nano-crystalline cellulose（NCC）was prepared through acid hydrolysis using dissolving pulp from hard wood,and then oxidized with sodium periodate to generate dialdehyde NCC.Oxidizing reaction parameters such as dosage of sodiumperiodate,pH,reaction temperature to time were investigated in detail.The results show that the optimized reactionconditions are as follows：sodium periodate to NCC mass ratio was 2,pH was 3,the reaction temperature was 40,℃ andreaction time was 4,h,and then dialdehyde NCC with 73%, of the content of aldehyde groups was obtained.The results ofcharacterizations with FTIR,XRD,AFM and the degree of polymerization（DP）show that dialdehyde NCC formed afteroxidation,crystallinity of both NCC and dialdehyde NCC changed compared with dissolving pulp cellulose.The NCC hasthe rod structure and its size decreased after oxidization.The DP decreased significantly after hydrolysis and decreased furtherafter oxidization with sodium periodate.