Comparison of tensile strength values for different types of filler in biocomposites with liquid natural rubber adhesive

The egg consumption rate in Indonesia is relatively high, which leaves eggshell waste. Likewise, clam shells, whose annual harvest can reach 200-300 tons of whole clams. The two shells can be used as fillers in composite materials because they have high levels of CaCO3. One of the natural materials that has the potential to be used as a composite binder is natural rubber. This study aims to obtain the mechanical value of biocomposites in tensile strength. This is achieved by comparing the value of tensile testing in the form of ultimate tensile strength values. In making these two biocomposites, the exact composition is 65% filler, and the same hotpress machine treatment with a temperature of 170°C, 0.7 MPa, and a time of 60 minutes. The data observed is tensile strength test data using the UTM MTS Landmark 100kN machine. Furthermore, the eggshell specimen was compared with the data of the comparator eggshell specimen, which was given a pressing pressure of 40 MPa. It was found that the specimen given a pressure of 40 MPa was superior with a UTS value of 25.008 MPa, yield strength of 24.985 MPa, young modulus of 6.406 GPa, and strain at fracture of ±0.025. Meanwhile, the best data from the specimen given a pressure of 0.7 MPa only got a UTS value of 18.684 MPa, yield strength of 12.192 MPa, young modulus of 3.174 GPa, and strain at fracture of ±0.041. Then, from the comparison between the two shells and eggshell composites with the same treatment using the normal distribution graph and the error bar graph, it was concluded that there were similarities and that there was no significant difference between the two biocomposites.