Polymer additives are added to polymers with a slogan: Low spending, high efficiency! But the same high effectiveness is achieved only if the appropriate additive is selected and used in sufficient quantities. One of the most attractive group of additives used in various polymers are additives that change the appearance of polymer products. This section will talk about additives called clarifiers. If we are going to see a polymer piece like a container, the size of the structural units of this polymer must be smaller than the wavelength of visible light. In the case of irregular or amorphous polymers such as PET, PC, PVC, PS and…, because all crystalline units do not form and the size of the chains is smaller than the wavelength of visible light, then all parts made of pure polymer will be transparent. But but we will face with the problem about crystalline polymers such as PP and PE. In fact, in PE and PP, during the cooling of the manufactured parts, crystals are formed that have dimensions larger than the wavelength of visible light. Here it can be concluded that the task of clarifying agents or Clarifier masterbatches is to prevent the formation of large crystals. But it is not that simple, In order to produce suitable clarifying additives, it is necessary to fully understand the crystallization mechanism and crystals of each polymer and to produce a specific additive for each polymer and in sufficient quantity under suitable process conditions (especially forming temperature, speed and cooling temperature). , Put these additives in the polymer piece. Due to the many uses of PP and its transparent types can be an alternative to PS, PET and even PC, transparent additives of this polymer have been commercialized. But due to the sensitivity of this user and achieving the desired results, you must be extremely careful while choosing the appropriate transparency. These clarifiers are generally from the sorbitol family and are produced and consumed as masterbatches. Recently, successful efforts have been made to produce transparent PE additives. In addition to creating transparency in the manufactured parts, the clarifiers also enhance the mechanical properties of the product due to the strengthening of the crystalline phase of the polymer. Also, the injection cycle of products is shortened due to faster crystallization and the production rate is increased due to these factors. For this reason, in applications where transparency is not important, A special procedure of additives called nucleating agents has been developed whose main task is to strengthen the mechanical properties and reduce the injection cycle. These factors also control shrinkage or alluvium. In addition to PE and PP, nucleating agents are also available for PAs and PETs. Polypropylenes are produced today that can even be an alternative to ABS in terms of mechanical properties by nucleating agents. Transparent and nucleating agents are engineering additives that with the right choice can create great effects and be effective in reducing costs.