**4.3 Impact strength properties for composite sheet material**

In order to find the impact capability of sample, impact test is carried out using IZOD – CHARPY digital impact tester machine. Absorbed energy obtained for six


**Table 8.** *Tensile strength result.*

#### **Figure 12.**

*Effect of the pulp ratio and thickness on tensile properties.*


#### **Table 9.**

*Impact test results.*

different (samples) composite sheets from the IZOD – CHARPY machine has been shown in figure. It has been observed from **Table 9** that maximum impact strength of 2.40 Kj/m2 is obtained for 55% pulp ratio sheet.

Further, pulp ratio of (55%) with 4 mm and 8 mm thickness has highest impact strength for 1.79 Kj/m2 and 2.4 Kj/m2 respectively. The impact strength of the composites increases with increase in fibre content (pulp ratio %). It may be due to during impact force, fibre pulls out and fibre breakage occurs at lower fibre loading of the polymer composites. At high fibre loading, the fibre crowding leads to easy debonding, which in turn increases the impact resistance, when compared with the impact energy of neat epoxy which is very less. It is observed that the impact strength increases.

Pulp ratio (35%) in composite sheet for both thickness levels of 4 and 8 mm, lower impact strength has been observed with decrease in pulp ratio % and epoxy resin concentration level. The optimum combination for the impact strength of the composites is pulp ratio of 55% and for both thickness levels as seen in **Figures 13** and **14**, respectively.

*Functional Application for the Corn Leaf Fibre to Make Reinforced Polymer Composites Sheet DOI: http://dx.doi.org/10.5772/intechopen.101656*

#### **Figure 13.**

*(a). Impact specimen (b). Broken specimen after impact strength testing.*

**Figure 14.** *Effect of the pulp ratio and thickness on impact strength properties.*
