Pengaruh Fraksi Volume dan Temperatur Perendaman Alkali terhadap Kekuatan Beban Kejut Komposit Serat Alang-Alang (Imperata Cylindrica)

The increasing need for strong, lightweight, and environmentally friendly materials is driven by the development of material technology. Composite materials are one type of material that is still being developed. Natural fibers are used as reinforcement in composites, which are a combination of matrix and reinforcement. This research method uses an experimental research type that aims to determine the mechanical strength of shock loads on composite materials reinforced with Imperata cylindrica fiber with an epoxy matrix using the hand lay-up method. An impact tester is used to determine the strength of the composite specimen test object, with variations in fiber volume fractions of 10%, 20%, and 30%, as well as immersion temperature treatments in 5% NaOH solution at room temperature, 50°C, and 80°C for 2 hours in a controlled manner in an oven. The results showed that variations in fiber volume fraction and alkali immersion temperature treatment each influenced the impact strength of the Imperata cylindrica fiber composite independently. The lowest impact strength test results were obtained at a fiber volume fraction of 10% with immersion at room temperature, which was 0.0559 J/mm², while the highest strength test results were obtained at a fiber volume fraction of 30% with immersion at a temperature of 50°C, which was 0.0832 J/mm². Imperata cylindrica fiber has the potential as an environmentally friendly composite reinforcement to replace fiberglass in certain applications, such as safety helmet shells.