Study of the Fracture Toughness Strength of Composites Made from Unsaturated Polyester with Pineapple Leaf Fiber Reinforcement

The development of natural fibre composites is needed to replace synthetic composites which are difficult to decompose. However, natural fibre composites have many weaknesses that need to be studied, including being brittle and easily cracked. One of the things carried out in this research is a material derived from unsaturated polyester reinforced with natural fibres from pineapple leaves and used to reduce the percentage of synthetic materials from polyester which can form composites that are easily decomposed. With this research, engineering in the engineering field such as raw materials for fishing boat bodies, tourist boat bodies, and fishing boats is very helpful. This unsaturated polyester mixture with 20% pineapple leaf fibre has the highest critical stress intensity factor of K_1c= 1,733 MPa.m<sup>0.5</sup>, an increase from K_1c= 0,779 MPa.m<sup>0.5</sup> in pure unsaturated polyester. This material has the highest performance and can withstand good fracture strength, making it suitable for engineering applications. This research increased the toughness and crack resistance of the UP material treated with the addition of the SN mixture by 222.47%.