*5.5.1 Interfacial and tensile strength*

The tensile strength of the untreated and treated banana fiber shown in **Figure 1** depicts that the infusing of nanoclay and structural alterations due to chemical treatment has a strong positive effect on the tensile properties of the fiber. The tensile strength, stiffness, and elongation at break values shown in **Figures 1**–**3** vary among untreated and treated fiber. The untreated fiber (UTBF) exhibited a tensile strength of 602 MPa and stiffness of 17 GPa with 4.3% elongation at break. An increase in tensile strength and stiffness after banana fiber was treated was with sodium hydroxide only (NTBF). The composite series exhibited tensile strength and stiffness of 713 MPa and 22 GPa. This performance depicts the effect of the chemical treating banana fiber using sodium hydroxide. A further increase in strength and stiffness was observed after the banana fiber was treated with a combination of sodium hydroxide and clay.

Composite reinforced with banana fiber treated with sodium hydroxide, and clay (N&CTBF) exhibited a tensile modulus of 43 GPa, approximately threefold of

**Figure 1.** *Tensile strength of composite series.*

**Figure 2.** *Tensile modulus of composite series.*

*Influence of Loading Nanoclay on Properties of the Polymer-based Composite DOI: http://dx.doi.org/10.5772/intechopen.108478*

**Figure 3.** *Elongation at the break for composite series.*

untreated fiber stiffness, and tensile strength of 918 MPa, 51% higher than what is obtained with untreated fiber. Removing weak strength phases such as wax, lignin, hemicellulose, and other impurities from the fiber could be the primary reason for the observed tensile strength and stiffness.

Furthermore, the reinforcement effect of the infuse nanoclay is another reason for a significant improvement in tensile strength and stiffness. The increase in tensile stiffness and strength may be attributed to interfacial bonding between the matrix and the fiber due to the presence of nanoclay in the composite.

However, a linear reduction in elongation at break was seen. Composite with untreated fiber exhibited the highest elongation value of 4.3%, followed by composite reinforced with banana fiber treated with sodium hydroxide only, which is 3.5%, and composite filled with banana fiber treated with a combination of sodium hydroxide and clay exhibited the lowest elongation of 3.1%. This decrease in elongation value may be attributed to the absence of banana fiber's waxy and amorphous phases, which were removed during chemical treatment.

#### *5.5.2 Temperature-dependent mechanical properties*

**Figures 4** and **5** show the effect of the chemical treatment given to banana fiber on dynamic mechanical properties such as storage modulus and tan α. It was observed that the composite reinforced with untreated banana fiber exhibited high storage modulus of 6380 MPa at room temperature and declined with a corresponding increase in temperature. Fibers treated with sodium hydroxide solution and montmorillonite/sodium hydroxide filled composite exhibited 7553 and 8328 MPa at room temperature. This result depicts that giving fiber chemical treatment using a combination of montmorillonite and sodium hydroxide is a viable way to improve temperature-dependent storage modulus. The composite with banana fiber treated using montmorillonite/sodium hydroxide exhibited a temperature-dependent modulus at room temperature, 32% higher than the composite with untreated banana fiber.

The tan α curves shown in **Figure 5** provided details on the composite series' phase transformation, damping features, and interfacial strength. An increase in tan α value with a corresponding increase in temperature is till attaining a maximum point, followed by a decline in temperature. The temperature where tan α reaches a maximum

#### **Figure 4.**

*Temperature dependence storage module of composite series.*

**Figure 5.** *Temperature dependence tan α of composite series.*

value, referred to as the glass transition temperature of the polymer, was identified and recorded. At this glass transition temperature, the polymer changes from an amorphous to a rubbery state under increased temperature.

Composite with untreated fiber, treated with sodium hydroxide, and montmorillonite/sodium hydroxide exhibited glass transition at 69°C, 69°C, and 72°C, respectively. This output implied that composite filled with fiber treated with montmorillonite/sodium hydroxide, and this performance might be attributed to the presence of nanoclay in banana fiber. Nanoclay is known for its good thermal properties and ability to delay polymer deformation from a glassy region into a rubbery region [30, 31, 34]. Thus, infusion and dispersion of nanoclay into fiber may have reduced the polymer deformation leading to increased glass transition of composite with fiber treated with montmorillonite/sodium hydroxide. This result trend corresponds with what is experienced in the storage modulus.

## *Influence of Loading Nanoclay on Properties of the Polymer-based Composite DOI: http://dx.doi.org/10.5772/intechopen.108478*

These findings proved that the advanced way of infusing clay into natural fiber (banana fiber) could be used to produce composite materials with improved properties for different applications. Going by this technique, clay concentration for producing composite using conventional methods such as resin casting method and vacuum infusion may reduce to minimal, eventually affecting composite production cost positively. We employ infusing nanoclay on acrylonitrile butadiene styrene printer layers using a 3D printer. This technique was used to develop a gear material and determine printed material's mechanical, thermal, and tribological properties. This idea was motivated by the challenging process of gear using conventional techniques, material selection, and production parameters [31]. The research aimed to reduce the time used for producing gear, selecting nanoclay to enhance the interfacial bonding acrylonitrile butadiene styrene printer layers toward developing more robust structures using relatively simple 3D printing processes.
