What are Micro-Plastics? Micro-plastics have not been defined in particular. They are just tiny particles that result from the disintegration of bigger plastic materials. However, most researchers say that any plastic smaller than 5 millimetres in size is a micro-plastic. Hence, these are really, really teeny-tiny! Plastics are made up of polymers, which are derived from fossil fuels. A whole lot of chemicals are added to the polymers—close to 10,000—to ensure that a given plastic has the desired properties...