Highly improved mechanical strength of aramid paper composite via a bridge of cellulose nanofiber

Abstract

A novel aramid paper composite based on pretreated meta-aramid fiber via the addition of cellulose nanofiber (CNF) was fabricated, and the mechanical strength and interfacial strength of the aramid paper composite were investigated. The results indicated that modified fibers showed higher roughness and more available hydrophilic groups. Besides, compared with the pristine aramid paper, it turned out that the tensile index, tear index and interlayer bonding strength of the paper composites with CNF increased by 2.04 times, 2.36 times and 3 times, respectively. In addition, tensile energy absorption (TEA) was also improved by an increment of 99.7% with 20 wt% CNF. These apparent evidences can be accounted for the following mechanisms. On the one hand, enhanced mechanical properties of aramid paper composite were derived from the strong hydrogen bonding or dipole–dipole coupling interaction between aramid fiber and CNF. On the other hand, significant reinforcement of interlayer bonding strength can be attributed to the pivotal bonding bridge and filling agent between aramid chopped fibers (ACFs) and fibrid, which could improve interfacial adhesion of paper sheet. The thin film structure like “spider web” or “silk” from SEM images indicated the CNF was used as a bridge actually.