Unlike isotropic materials, the functional requirements can affect the design of components made of composites. And because natural fibers play a critical role in achieving the desired specific requirements of the composites as engineered materi­als and because the incorporation of these fibers in matrix polymers have been found helpful in determining the properties of the final composites, the appropriate selection of the reinforcement and the polymer as well as other technical aspects should be fairly executed and optimized. That is, several criteria affect the final desired characteristics of the natural fiber composites to be suitable for particular application. These criteria were classified into levels by AL-Oqla and Sapuan (Al-Oqla and Sapuan 2014) to be as:

1. The Natural Fiber Level: where different properties regarding natural fibers have to be concerned.

2. Matrix Level: where different properties regarding the polymer matrix have to be concerned.

3. The Composite Level: where different properties regarding the composite itself have to be concerned. That is, the characteristics of the final composites are not necessarily being exactly similar to any of these for fibers or matrix.

4. The General Performance Level: where different properties regarding the com­posite performance have to be taken into account such as mechanical properties, weather resistance, bio stability, life cycle, etc.

5. The Specific Performance Level: where particular requirements regarding a specific desired function and application should be considered. For instance, for automotive applications: composites’ weight, thermal and acoustic insulation properties, occupational health and safety properties have to be considered. An illustrative diagram of the suggested levels is shown in Fig. 1.14.

The classified criteria that affect the proper selection of the natural fiber compos­ites are shown in Tables 1.6 and 1.7 . According to these criteria, it was approved that date palm fibers are one of the most potential and available fiber types that can be utilized to form attractive natural fiber composites for different applications par­ticularly in the automotive industry (Al-Oqla and Sapuan 2014).

Fig. 1.14 Levels of factors that affect the proper selection NFC materials. From Al-Oqla and Sapuan(2014)

Natural

Fiber

Composites

Selection