An analysis of the properties of recycled PET fiber-gypsum composites

The production of composites materials has gained importance due to the in-creasing and more complex needs of today. Materials used for composites, where the aim is to produce products that have better properties compared to the com-ponents forming the main body, can be composed of products obtained from raw materials or recycled products. By adding PET fibers, which are among recycled products, into the composites, the use of limited raw material resources and the harm to the environment during the processes during the lifecycle of the prod-uct is minimized. Additionally, gypsum, which is used as matrix in the compos-ite, is easily obtainable, has adequate raw material resources, is easily given form, produces a clean-flat surface, has sufficient tensile and compressive strength and is a good humidity equalizer and sound regulator. However, gypsum has a low impact strength and toughness value. As it is necessary to increase its impact re-sistance, some research is carried out to this end. In this study, composite ma-terial is produced by adding polyethylene terephthalate fibers that are recycled products manufactured from recycled PET bottles and which have not been tried before and PVA based adherence-enhancing additive into the gypsum matrix to improve the properties of gypsum. Test results show that with the addition of fiber the flexural strength of gypsum has somewhat decreased but the addition of the adherence-enhancing additive has considerably increased the compressive and flexural strength. As expected from fiber reinforced composites, the impact and toughness values of the material has considerably increased. The positive effect of the adherence additive between the gypsum matrix and the fiber is clearly visible in the micro analysis carried out.

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