Mechanical Properties of Natural Fiber Containing Polymer Composites

We have studied the mechanical properties of ethylene vinyl acetate (EVA) and cellulose acetate (CA) composite containing cellulosic natural fibers (Sterculia villosa) and tried to explain with the help of mixing of fiber in the composite. It is observed that the tensile strength (TS) of EVA composite decreases with the addition of fiber. Whereas in a CA composite, TS increases or reinforcement happens with the fiber content. This anomalous trend could be explained with the adhesion of fiber with the polymer matrix in the composite. The composite shows the same increasing trend for flexural strength (FS) up to a certain composition of fiber. With the further addition of fiber, we have found decreasing FS for the EVA composite, but a gradual increase in the CA composite with the fiber content. It is thought that fiber is well distributed in the CA composite and that the fiber-matrix could bear the load resulting in an increase of FS. This consideration can be well explained from the SEM picture that shows fiber forms a domain in the EVA composite or coagulation of fiber, as a result the FS decrease, but there is no such type of coagulation in the CA composite, resulting in increasing TS and FS with the fiber content. Toughness of the composites are also compared. It is believed that the cellulose-containing EVA and CA composites will be environment-friendly. We also suggest that this composite could be used in a low weight application such as gasket materials, toothbrushes, spoon handles, mirror frames, partition panels, etc.