Study On The Functional Aerogels Derived From Cellulose Nanofibers Existed In The Bamboo

A lot of cellulose was contained in low-quality bamboo or bamboo leaves,it would have a huge economic and ecological benefits if high-quality cellulose could be extracted and used in industrial production.With the deepening and development of nano-inorganic materials in various industries and disciplines,the effective synthesis of inorganic nanoparticles with the components extracted from bamboo-based fiber resources and their derivatives is a prerequisite for the current research hotspot.Using these low-quality bamboo or bamboo leaves as raw materials,the micro-nano structural units contained in them were extracted,the bamboo-based cellulose aerogels functional materials were prepared by fine assembly,further synthesized with inorganic nanoparticles.Functional composites that impart new properties such as superabsorbent,absorbing properties,self-reporting stress sensitive electric,fire insulation,and photocatalysis to improve the use of low-quality bamboo or bamboo leaves.The development of high value of new cellulose aerogels based composite materials for the efficient use of bamboo-based fiber resources to open up a new way of thinking and ways for the further development and utilization of bamboo-based materials to provide new research ideas and scientific methods.The main conclusions are as follows:(1)In the current research,high-purified natural cellulose nanofiber(CNF)from bamboo leaf(BL)was successfully obtained via a combination of chemical pretreatment and ultrasonic technique.The as-obtained CNF had an average diameter of 53.2 nm and a high aspect ratio of about 2600.The crystallinity of CNF was 55%,which increased by 27% compared to that of the raw BL.With further modification by methyltrimethoxysilane(MTMS),the aerogel derived from the obtained CNF through a freeze-drying process showed superior multifunctions of superabsorbent performance,thermal isolation,and sound absorption.The study might provide a new family of nature-based nanocellulose.(2)Spawns structure of Zn O rod-like wrapped in the cellulose nanofibers was successfully fabricated through a facile one-step hydrothermal method,and their electromagnetic wave absorption properties were investigated.The structure and properties of the composite aerogel were characterized.The enlarged morphology images showed that the as-prepared cellulose nanofiber/ZnO samples were spawns structure of ZnO rod-like wrapped in the cellulose nanofibers.The composite aerogel in a wax matrix exhibited excellent electromagnetic wave absorption performance over 2-18 GHz.The widest absorption bandwidth of 30 wt% contained with reflection loss values less than-10 dB was up to 12 GHz(6-18 GHz)at the thickness of 5.5 mm and the minimum reflection loss value reaches-26.32 dB at 15.2 GHz when the thickness of the absorber was 3 mm.(3)Cellulose nanofiber/AlOOH aerogel for flame retardant and thermal insulation was successfully prepared through hydrothermal method.Their flame retardant and thermal insulation properties were investigated.The morphology image of the cellulose nanofiber/AlOOH exhibited spherical AlOOH with an average diameter of 0.5 μm was wrapped by cellulose nanofiber or adhere to them.Cellulose nanofiber/AlOOH composite aerogels exhibited excellent flame retardant and thermal insulation properties through the flammability test,which indicated that the as-prepared composite aerogels would have a promising future in the application of some important areas such as protection of lightweight construction materials.(4)A self-reporting aerogel toward stress sensitive slectricity(SSE)was presented using an interconnected 3D fibrous network of Ag nanoparticles/cellulose nanofiber aerogel(Ag/CNF),which was prepared via combined routes of silver mirror reaction and ultrasonication.Sphere-like Ag nanoparticles(AgNPs)with mean diameter of 74 nm were tightly anchored in the cellulose nanofiber through by the coherent interfaces as the conductive materials.The as-prepared Ag/CNF as a self-reporting material for SSE not only possessed quick response and sensitivity,but also be easily recovered after 100 th compressive cycles without plastic deformation or degradation in compressive strength.Consequently,Ag/CNF could play a viable role in self-reporting materials as a quick electric-stress responsive sensor.