Introduction

In the previous lecture we have introduced the composite. Then we have seen the constituents of a typical composite material. Further, based on the reinforcement, the classification of the composite was presented.

In the present lecture we will introduce natural fibres and some advanced fibres. We will see, in brief, the key features of these advanced fibres.

What are the functions of a reinforcing agent?

The functions of a reinforcing agent are:

1. These are the main load carrying constituents.
   
   
2. The reinforcing materials, in general, have significantly higher desired properties. Hence, they contribute the desired properties to the composite.
   
   
3. It transfers the strength and stiffness to the matrix material.

What are the functions of a matrix material?

The matrix performs various functions. These functions are listed below:

1. The matrix material holds the fibres together.
   
   
2. The matrix plays an important role to keep the fibres at desired positions. The desired distribution of the fibres is very important from micromechanical point of view.
   
   
3. The matrix keeps the fibres separate from each other so that the mechanical abrasion between them does not occur.
   
   
4. It transfers the load uniformly between fibers. Further, in case a fibre is broken or fibre is discontinuous, then it helps to redistribute the load in the vicinity of the break site.
   
   
5. It provides protection to fibers from environmental effects.
   
   
6. It provides better finish to the final product.
   
   
7. The matrix material enhances some of the properties of the resulting material and structural component (that fibre alone is not able to impart). For example, such properties are: transverse strength of a lamina, impact resistance