**1. Introduction**

In recent times, the application of natural fiber polymer composites (NFPCs) for structural purposes has increased [1–7]. In the past, carbon fibers and basalt fibers reinforced polymer composites were commonly used due to their high performance to cost and high strength to weight ratios [8–15]. However, due to fundamental concerns, such as high cost of materials, durability, bonding integrity and gap in the development of standards for practice of abrasing or wearing of machines among others, their uses have been limited [16–19]. More importantly is the environmental concerns, which has strengthened the call for complete replacement of all synthetic fibers. Hence, the increase in research output for possible replacement of synthetic fibers with natural fibers in polymer composites [20–22].

Structural materials required for structural applications encompass materials that are primarily for the purpose of stress transmission or support. Structural materials may be in transportation (aircraft and automobiles), construction (building and roads), or in components used for the purpose of protecting the body (helmets and body armor), energy production (turbine blades), etc. [23–25]. Also,

those used in microelectronics, are designed to meet specific performance requirements. Structural requirements may vary based on end use; hence the requirement for a material to be used for vehicle part may differ widely from what is required for manufacturing casing for electronic equipment. Generally, of more interest are the following properties: mechanical, thermal, electrical conductivity, dimension stability, water absorbability, etc. [26–31]. This work intends to critically review the mechanical requirements and suggest ways of improving the mentioned properties for structural and biomedical applications.
