## 5 Mechanical Properties of the Natural Fibers Reinforced Epoxy Composites  
Table 4 includes the mechanical characteristics of the epoxy bases' natural fiber composites and the effect of fiber loadings, orientation, lengths, and treatments. The chemical treatments of the fibers decrease the moisture content and other impurities that restrict the adhesion between fibers and matrix, which leads to improved mechanical strength. The plasma treatment of the fibers also improves mechanical characteristics. Still, longer plasma treatments of the fibers reduce the mechanical characteristics as the degradation of the fibers occurs due to the longer time of plasma treatment. The fiber treatments and optimum fiber loadings show the optimum properties of the NFRCs that lead the NFRCs to different constructional applications such as automobiles, aerospace industries, and housing applications.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Composites (wt\%/wt\%)** & \begin{tabular}{c} **Tensile** \\ **Strength (MPa)** \\ \end{tabular} & \begin{tabular}{c} **Flexural** \\ **Strength (MPa)** \\ \end{tabular} & \
\begin{tabular}{c} **Impact** \\ **(J/m)** \\ \end{tabular} &
\begin{tabular}{c} **Impact Energy** \\ **(kJ/m\({}^{2}\))** \\ \end{tabular} & **Hardness** & **Ref.** \\ \hline Coir/epoxy (30/70), 5 mm fiber length & 3.208 & 25.41 & - & 16.0 & 15 HV & [92] \\ \hline Coir/epoxy (30/70) 20 mm fiber length & 9.15 & 31.28 & - & 16.5 & 12.6 HV & [92] \\ \hline Coir/epoxy (30/70) 30 mm fiber length  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Composites (wt\%/wt\%)** & **Tensile Strength (MPa)** & **Flexural Strength (MPa)** & **Impact Strength (J/m)** & **Impact Energy (kJ/m\({}^{2}\))** & **Hardness** & **Ref.** \\ \hline Jute/epoxy (35/65) & 38.00 & 10 & - & 10.2 & & [67] \\ \hline Banana/epoxy (5/95) & 26.3 & 46.2 & - & 220 & 54.5 HRB & [94] \\ \hline Banana/epoxy (10/90) & 27.2 & 52.5 & - & 2400 & 60.8 HRB & [94] \\ \hline Banana/epoxy (15/85) & 30.4 & 56.3 & - & 2700 & 65.4 HRB & [94] \\ \hline Banana/epoxy (20/80) & 29.4 & 54.3 & - & 2600 & 68 HRB & [94] \\ \hline Coir/epoxy (30/70) & & & - & 4 J & 36 HRC & [69] \\ \hline Banana/epoxy (30/70) & & & - & 5 J & 63 HRC & [69] \\ \hline Sisal/epoxy (30/70) & & & - & 4 J & 54 HRC & [69] \\ \hline Pine/epoxy (10/90) & 53 & 61 & - & 18 & - & [95] \\ \hline Pine/epoxy (20/80) & 50 & 57 & - & 16 & - & [95] \\ \hline Pine/epoxy (30/70) & 39 & 43 & - & 14 & - & [95] \\ \hline Pine/epoxy (40/60) & 36 & 38 & - & 11 & - & [95] \\ \hline Bagasse/epoxy (3/97), 5 mm fiber length & 26.36 & - & - & 2.4 & 25 HV & [26] \\ \hline Bagasse/epoxy (3/97), 10 mm fiber length & 29.23 & - & - & 2.5 & 39 HV & [26] \\ \hline Bagasse/epoxy (3/97), 15 mm fiber length & 23.57 & - & - & 3.7 & 32 HV & [26] \\ \hline Flax fabric/epoxy (26.64/73.36), 2 mm laminate thickness & 35.59 & - & - & - & [96] \\ \hline Flax fabric/epoxy (21.17/78.83), 4 mm & 29.74 & - & - & - & [96] \\ laminate thickness & & & & & \\ \hline Agave/epoxy (30/70), untreated, 3 mm fiber length & - & 55 & 120 & - & - & [97] \\ \hline Agave/epoxy (30/70), NaOH treated, 3 mm fiber length & - & 60 & 140 & - & - & [97] \\ \hline Agave/epoxy (30/70), untreated, 7 mm fiber length & - & 41 & 100 & - & - & [97] \\ \hline Agave/epoxy (30/70), NaOH treated, 7 mm fiber length & - & 48 & 115 & - & - & [97] \\ \hline Agave/epoxy (30/70), untreated, 10 mm fiber length & - & 41.5 & 55 & - & - & [97] \\ \hline Agave/epoxy (30/70), NaOH treated, 10 mm fiber length & & 39 & 63 & - & - & [97] \\ \hline Areca/epoxy (50/50) & 27.50 & 25.00 & 93.33 & - & - & [98] \\ \hline Ramie/epoxy (40/60) & 86 & 103 & & - & - & [99] \\ \hline Pseudo stem Banana-epoxy & 45.57 & 73.58 & 92.66 & - & - & [100] \\ \hline Ground nuts shell/epoxy (12.5/87.5) & 36.66 & 43.43 & 7.91 & - & 6.8 HRF & [101] \\ \hline Rice husk/epoxy (12.5/87.5) & 12.71 & 22.72 & 4.27 & - & 6.9 HRF & [101] \\ \hline Coir pith-epoxy & 9.00 & 23.00 & 18.67 & - & - & \\ \hline \hline \end{tabular}
\end{table}
Table 4: _Cont._