A new nanocellulose prepared from waste coconut shell fibers based on a novel ultrasonic – Active agent combination method: Preparation principle and performances in cement matrix

Abstract

The depletion of non-renewable resources and the current severe environmental problems, inspire a popular new trend of research on the rational development and utilization of renewable resources. Plant fibers, as a type of building material with abundant renewable resources, attract extensive attention in the field of building materials. However, in cement matrix composites, the inhomogeneity of plant fiber properties together with the swelling and agglomeration of large-size cellulose after absorbing water will lead to the microstructure defects. Although these drawbacks can be overcome by diminishing the fiber size to nanoscale, cellulose still have limited application in cement matrix composites because of the complexity of the existing nanoscale cellulose preparation method and the difficulty in dispersing in cement matrix composites due to the mesh structure of cellulose fibers. Therefore, to solve this problem, our team developed an environmentally friendly ultrasonic and active agent (U-A) combined preparation method, which can greatly improve the nanocellulose preparation efficiency to prepare rod-shaped and easily dispersed nanocellulose fiber (CNF) from discarded coconut shell to solve the agglomeration of mesh nanocellulose in cement matrix composites. This paper mainly studies the influence of CNF on the mechanical properties of cement matrix composites and observes the microstructure and composition of CNF/OPC by using scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that proper CNF incorporation could improve the compactness of cement matrix composites, which may increase the compressive strength up by 15.86%, the flexural strength by 26.62%, the initial crack load by 69.61%, the fracture peak load by 73.31%, and the fracture energy by 24.2%.