Silk Fibers and their Unidirectional Polymer Composites - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 85

Figure 18. Variation of impact strength with fiber volume fractions of composites.
hardness testing of Composites
It can be noticed from the hardness test results presented in Figure 19 that the hard-
ness increases with fiber loading. Hardness tests showed not very profound variation
among all the composites.
Figure 19. Variation of hardness with fiber volume fractions of composites.
CoNClusioN
The physical and mechanical properties of raw and alkali treated silk fibers were eval-
uated first. Based on the experimental results, it can be concluded that the Young's
modulus of silk fibers increases when span length is increased. With an increase in
the span length, tensile strength, strain to failure, and machine constant (α) decrease.
In comparison of raw and alkali treated silk fibers, alkali treated ones give the higher
Young's modulus and tensile strength.