Synergistic reinforcement mechanism of basalt fiber/cellulose nanocrystals/polypropylene composites

In this article, we prepared novel basalt fiber (BF)-reinforced polypropylene (PP) composites based on the synergistic reinforcement of cellulose nanocrystals (CNCs). First, we compared the enhancement effect of CNCs and silane coupling agent-modified BFs on PP, showing that the enhancement effect of the former was more significant. Subsequently, to further improve the mechanical properties of the composites, CNCs were introduced into the BF-reinforced PP composite system as the third phase, and the results suggested that their combination with BFs could synergistically strengthen the PP matrix composites. Simultaneously, the study also shows that when the mass percentage of CNCs and BFs are 1 and 30%, respectively, the composite achieves the highest mechanical strength, which is 64.31% higher than that of the PP matrix. The systematic characterization revealed the synergistic enhancement mechanism: on the one hand, CNCs not only promoted the improvement of PP crystallinity by heterogeneous nucleation but also formed a wedge-shaped structure between them and BFs through hydrogen bonding to prevent PP molecular movement; on the other hand, the BFs promote not only the extrusion crystallization of the resin matrix but also the network structure formed by the appropriate content of BFs can realize the rapid transmission of external stress.