THE EFFECT OF BORAX ON THE ELASTICITY OF SLIME Mieke Jones (Year 10) Science Faculty, The Illawarra Grammar School, Western Avenue, Mangerton, 2500 Abstract Slime is a toy that is enjoyed by children all over the world. In this work, PVA glue and borax solution was used to create the non-Newtonian fluid, slime. This experiment involved creating 3 separate slimes with different amounts of borax solution. The elasticity of slime was evaluated and in particular the effect of borax on the elasticity of the slime. To evaluate the elasticity each slime was stretched along a ruler until they snapped and the final length at breaking was recorded. The study found that the slimes with a lower amount of borax solution in them had a higher elasticity.
Introduction Polymers are a class of natural or synthetic substances comprised of very large molecules which are made up of multiples of smaller units called monomers. When monomers join together to make polymer, they join by forming covalent bonds through sharing electrons (Evans, D & Watkins, S 2017). Polymers can be found in living organisms, minerals and many man-made materials. Polymers are used extensively in children’s toys (Polymer, 2021). Polyvinyl acetate (PVA) glue is a vinyl polymer (Wikipedia 2021) which is made by chemically combining vinyl acetate monomers into long chain-like network molecules (Polymerisation, 2020). The PVA polymer is used in many applications. It can be found in paints, food additives and adhesives for wood, paper and cloth (Oksman, K 2017). Crosslinking is the process of joining long chain-like network polymer molecules together. This process can alter the overall structure of the polymer and change its
properties, for example its elastic behaviour (Kuckling, D 2012). PVA can be cross-linked with different cross-linkers. One such cross-linker is sodium tetraborate, commonly known as borax. Many studies have been done on cross-linking PVA by using borax or boraxbased substances and cross-linking of solutions of PVA and water resulting in gellike materials has also been reported. Some studies also showed that borax type additives also cause the PVA to become more mouldable (Oksman, K 2017). In 1976 Mattel Toys released a product called Slime that was designed to be a gross, oozing substance. It was a light green coloured and was supplied in a little green garbage can. Presumably during the development of this product by Mattel the effect of the cross-linker on the base polymer would have been studied to provide a product with the desired properties. This report investigates the cross-linking reaction between PVA glue and borax and the effect of increasing volume of borax on the properties of the final polymer. (The Science behind Slime, 2017.). 49
