Method of Increasing the Fracture Toughness of Unsaturated Polyester with the Addition of Vinyl Ester as a Material for Automotive Body

Unsaturated polyester is the polymer material most widely used for matrix composites in the field of construction engineering, including for ships, automotive components and other engineering fields. The weakness of this polymer is that it is brittle and brittle and is unable to withstand cracking loads due to having cross-linked molecules that easily link together. The study to improve it was mixing with vinyl ester which succeeded in making the polyester crack resistant which was tested using a CTM machine and the fracture was observed using an SEM microscope. The test results showed that the polyester polymer mixed with 30% vinyl ester showed the highest increase in fracture strength, which was equal to K1c = 1.67 N.mm0.5 compared to pure polyester, only K1c = 0.77 N.mm0.5 can increase (216 %). Increasing the mixture content of 30% vinyl ester in polyester will change the brittle nature of unsaturated polyester to become more resilient because the vinyl ester molecules break the bonds of the polyester molecular chains.