Study on new composite materials in engineering products with promising physical and mechanical properties has been considered as one of the fields of concern in recent decades. Strength, hardness and fatigue properties make engineering structural more flexible. They are extensively used in the aerospace industry, mechanical engineering applications and parts, electronic packaging, vehicle and aircraft structures, process industry equipment, as well as in biomedical equipment. Disposing of composite wastes however, are very difficult because of its structure and compositions. Hence, composite materials recycling has become one of the major measures of the future. This study seeks to analyse the present state of engineering plastics using natural fibers in their properties and manufacturing techniques. The effects of various chemical treatments on natural fibres’ mechanical and thermal properties have been studied in strengthening thermosetting and thermoplastics composites. The mix ratio of polymer waste used from the industry sector with natural fiber is expected to rise in the future, thus issues regarding recycling need to be tackled. It concluded that chemically treated natural fibre improved the adhesion between fibre surface and polymer matrix, which gradually increased the properties of natural fibres incorporated composites.

This research investigated the tensile and water absorption properties of kenaf fibre mat/polyester composites. Treatment using acetylation method has been introduced to improve the properties of product manufactured. The effects of acetylation treatment with three variations of time that were 1, 4 and 24 hours on the kenaf fibre mats were investigated. The MOE of the tensile of treated fibre mat/polyester composite for 1 hour was the highest with value 4589.61 MPa. The tensile strength of treated fibre mat/polyester composite for 4 hours was the highest with value 0.6213 MPa. For water absorption test, the results showed that fibre mat/polyester composite with treatment duration for 1 hour had the lowest water absorption that was 1.23% compared with treatment duration for 4 hours and 24 hours. For overall it can be concluded that the treatment duration of 1 hour was recommended for acetylation method when compared with 4 hours and 24 hours duration treatments. Using acetylation treatment on the kenaf fibre mat/polyester composites was showed improvement on composite and was recommended in short duration of treatment.

The mechanical properties of natural fibre polyester composite was influenced by bonding efficiency between matrix and polyester matrix. This efficiency was related with the natural fibre and matrix characteristics. The natural fibre has a hydrophilic properties where else the polyester has a hydrophobic properties. The existent of organic and inorganic substances on the surface of natural fibre also contribute to the bonding strength. The modification using chemical treatment such as acetylation can overcome this problem. The chemical reaction participates in a long period cannot be completed in a short duration. The addition of some catalyst as an agent to speed up the reaction make the chemical reaction totally completed in short duration. In this study kenaf (Hibiscus cannabinus) polyester composite were manufactured and treated with acetic anhydride solution in 3 different percentages of catalyst that were 0.013%, 0.026% and 0.039% . In order to speed up the process modification in acetic anhydride solution catalyst (FeCl3) was added. Catalyst acts as a medium to complete reaction in limited time.It was found that,mechanical properties of polyester composite with addition of catalyst showed an increased trend and the highest was polyester composite with addition 0.036% of catalyst.