Examination of the effects of nucleatings on polypropylene final product properties

One of the main reasons for the intensive use of polymers is that they can be easily shaped under heat and pressure and that their characteristics can be changed by using additives and fillers. A linear polymer melting under the heat effect while shaping has an amorphous structure at high temperatures, and its polymer chains are randomly oriented. By cooling the solid polymer structure at low temperatures, the polymer chains try to be in an order (crystallize) to reduce the energy levels. In the meantime, the polymer chains tend to remain in a random sequence since their entropies are higher. The chains that want to be in a certain order and the chains that want to remain in a random sequence are balanced at a point. With this balancing, a crystal structure is formed at certain ratios in the polymer. Crystallization may occur in two different forms, being homogeneous and heterogeneous. In homogeneous crystallization, the polymer spontaneously crystallizes during hardening. Homogeneous crystallization is completed with the completion of the growth of crystals and with the termination of hardening. In heterogeneous crystallization, crystallization begins around a material/additive that is found in the polymer and increases or initiates crystallization. The polymer chains are oriented around these particles and enter the process of crystal growth. The additives used to initiate crystallization in heterogeneous crystallization are named a nucleating agent (NA). It has been stated by many researchers that NAs increase the crystallization of the material to which they are added. NAs affect the rate of the crystal nucleus formation, the number of crystal nuclei, and the size of crystal spheres in the materials they are added into, and accordingly, the materials exhibit better mechanical and visual characteristics (transparency). In this study, products and test samples with different geometries will be produced by using the injection and extrusion methods by adding NAs at different ratios into the polypropylene (PP) raw material. It is aimed to determine the effects of the ratios of NA additions into the PP structure on the final product characteristics, such as crystallization, improvement of mechanical properties, and an increase in transparency. Mechanical and thermal tests will be applied to the materials in order to determine the effect of the NA addition to the products after production. Microstructure imaging will be performed with a scanning electron microscope (SEM) to determine the effect of NAs on the microstructure.