Microstructure And Mechanical Properties Of Epoxy – Rice Husk Ash Composite

ABSTRACT

This study is about the production and characterization of epoxy-rice husk

ash composite. Composites were produced at 10%,20%,30%,40% and 50%

volume fraction of Rice Husk Ash(RHA) fillers and the epoxy was cast neat at

0%RHA which served as the control .The microstructure of the composites were

studied with Scanning Electron Microscopy(SEM) and Energy Dispersive X-ray

Spectroscopy(EDX).Mechanical properties of the composites such as tensile

properties(tensile stress, tensile strain, Young’s modulus, tensile strength and

percentage elongation at fracture),compressive strength, toughness, flexural

strength and hardness were experimentally determined in the engineering

labouratory using hounsfield (monsanto) tensometer, charpy v-notch impact

testing machine, flexural testing machine and Rockwell hardness testing machine.

The Scanning Electron Microscopy (SEM) analysis showed that interfacial

interactions existed between the rice husk ash particles and the epoxy matrix.

Energy Dispersive X-ray Spectroscopy (EDX) analysis indicated that interfacial

reactions existed between the epoxy matrix and the rice husk ash particles

because the composites did not contain homogenous elements. However each of

the composites contained C,O,Si and Cl while the cast neat epoxy(control)

contained C,O and Cl. Results of the mechanical property tests showed low gain

in hardness, toughness, flexural strength and Young’s modulus. The tensile

properties showed: that at 40%RHA the highest tensile strength of 37.006MPa was

obtained, the cast neat epoxy (control 0%RHA) had the best Young’s modulus of

356.538MPa and percentage elongation at fracture improved from 1.3% to 2.0%

as volume fraction of rice husk ash increased from 0% to 10%,20%,30%,40% and

50%.Increasing the volume fraction of rice husk ash from 0% to 10%,

20%,30%,40% and 50% led to decrease of these mechanical properties: toughness

from 2.0J to 0.3J,hardness from 344hardness value to 144 hardness value and

flexural strength from 6.0Mpa to 1.50Mpa.There was significant improvement in

the compressive strength of the composites from 15.75MPa to 18.75MPa as the

volume fraction of rice husk ash increased from 0% to 10%,20%,30%,40% and

50%.It was deduced from the study that epoxy-rice husk ash composite is

suitable for engineering applications subjected to compression. Surface coating of

rice husk ash could be used to improve its adhesion to the epoxy matrix in order

to enhance the mechanical properties of the composites for other engineering

applications.