Dynamic mechanical analysis and free vibration behavior in chemical modifications of coconut sheath/nano-clay reinforced hybrid polyester composite

Abstract

Naturally woven coconut sheath, a new natural fiber available in the form of woven mat is used as fiber reinforcement in polyester matrix. The hybridization effect of montmorillonite (MMT) on naturally woven coconut sheath/polyester composite has been investigated experimentally for free vibration characteristics using impulse excitation technique (IET). In the present study, naturally woven coconut sheath/clay-reinforced hybrid polyester composites were fabricated using a compression molding machine. The effect of organoclay addition (1, 2, 3 and 5 wt%), alkali (ATC) and silane treatment (STC) of the coconut sheath surface on free vibration characteristics were analyzed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were used to characterize the morphology of coconut sheath and structure of clay dispersed polyester. The dynamic mechanical analysis (DMA) and Fourier transform infrared (FTIR) analysis were carried out to analyze the effect of surface topology on chemically treated coconut sheath. The mechanism of chemical modifications on natural frequencies and the resultant improvement in the temperature dependence mechanical properties have also been reported. Enhanced vibration properties are observed up to 3 wt% of clay dispersion in hybrid composites, then it gets reduced for higher clay (>3 wt%) content. Modal damping of the hybrid composite is influenced by the addition of nanoclay and the surface treatments of the coconut sheath. Experimentally obtained natural frequencies are in good agreement with analytical and numerical results.

4-Methylcatechol-treated Jute-Bamboo Hybrid Composites: Effects of pH on Thermo-Mechanical and Morphological Properties

“…6 and 7, respectively. Figure 6 shows the decrease in the storage modulus with increasing temperature because of the dilute nature of the polymer at all of the pH conditions (Rajini et al 2013). It was clearly shown that the highest storage modulus (E') was obtained for F5pH10 at room temperature.…”

Dynamic mechanical and thermogravimetric analysis of PTFE blended tailor-made textile woven basalt–vinyl ester composites

“…The rectangular composite specimens of size 50 Â 10 Â 3 mm 3 were used [25]. The test was conducted by using a three-point bending mode.…”

Influence of redmud on the mechanical, damping and chemical resistance properties of banana/polyester hybrid composites

“…However, for the specimen in the form thin rectangular section can be analyzed more convincingly using impact hammer technique as per the previous research outcomes [29,35,36]. Accordingly, from the literature the standard specimen of size 200 Â 20 Â 3 mm composite plate was selected for the free vibration analysis.…”

“…However, among various particle size the decreasing particle size can have better strength compared to larger particle size for a fixed wt% of filler content. It is a well known fact that the decrease in particle size can increase the surface to contact area of the filler in bulk matrix [36]. It also ensures the uniform dispersion of redmud in polyester matrix from the increasing value of tensile strength.…”

“…Prabhakaran and Sivakandan [34] carried out free vibration studies of glass fiber reinforced epoxy composites with varying stacking sequence. Rajini et al [35,36] studied the effect of montmorillonite (MMT) clay with naturally woven coconut sheath reinforced polyester composites on mechanical and free vibration properties. The damping properties of coconut sheath/polyester composites were found to be better compared to glass fiber composites for the same wt% of fiber content.…”