3.1. Grafting of CNT on the ramie fabric
The schematic representation for the mechanism of ramie fiber surface treatments is shown in Fig. 2. For the alkali treatment of ramie fiber, the NaOH reacts with the hydroxyl groups of the ramie fiber as shown in Fig. 2(a). During silane treatment, the hydrolysis of silane takes place initially (Fig. 2(b)) which then reacts with the active hydroxyl functionalities in ramie fiber (Fig. 2(c)). Each silane molecule has three silanol (Si-OH) groups. For CNT treatment, first the silanised CNT is produced by the chemical reaction between silanol groups and the hydroxyl functional groups present in MWCNT (Fig. 2 (d)). The silanized CNT is then grafted on the surface of ramie fiber …show more content…
SEM
The SEM images of ramie fiber before and after chemical treatment are shown in Fig. 3. The surfaces of untreated and the alkali treated ramie fiber were smooth (Fig. 3(a) and (b)) whereas the surfaces of silane treated (Fig. 3(c)) and the CNT treated fiber (Fig. 3(d)) showed roughness which is attributed to the chemical reactions of the ramie fiber with the silanol functional groups. The clear evidence of CNT on the ramie fiber is observed on the CNT treated fiber. However, the grafting is not uniform and some agglomerates were observed on ramie …show more content…
… The storage modulus is closely related to the load bearing capacity of the material. The storage modulus of CNT-grafted ramie fiber composite is high compared to the untreated, alkali-treated and silane-treated fiber composites. This indicates that the fiber/matrix adhesion is high in CNT-grafted fiber composite, and grafting with CNT is best method for improving the interfacial adhesion compared to alkali and silane treatments.
The loss modulus reflects the amount of energy dissipated during the strain process. The untreated ramie fiber composite has poor interfacial bonding and the surface treatments improve the enhance the interfacial bonding as seen in Fig. … The maximum heat dissipation occurs at the temperature where loss modulus is maximum indicating the glass transition temperature (Tg) of the system. The increase of Tg is associated with the decreased mobility of the matrix chains, which is an indication of improved interfacial adhesion between the fiber and the