Thermal Analysis and Quality Control of Polyolephines

In the work, thermal studies of compositions based on polypropylene were carried out and, depending on the composition of the composition, a comprehensive assessment of the quality of materials of polymer automotive components was carried out, since comprehensive quality control of materials is the confidence that the finished products are of high quality, which is always maintained at the official level. Comprehensive studies of the quality of the material of automotive components products depending on the content of filler-talc and high-density polyethylene HDPE in the polypropylene composition are proposed, consisting in evaluating the thermophysical parameters of the composition and the effect of the composition on the physicomechanical properties of the finished product. It was revealed that the samples of the details of various batches differ in the composition of the polymer matrix from the initial required raw material of the PP composition. It was determined that HDPE is present in the PP composition, which can have a negative effect on the quality of finished products according to the required level of physical and mechanical characteristics. Thus, studies using differential scanning calorimetry showed that two minimums are observed in the samples of materials of automotive components products: the first of two minima (endotherm) indicates the melting of polyethylene (130-135 degrees C), which occurs at a lower temperature, and the second, observed at a higher temperature, corresponds to the melting of polypropylene (165-170 degrees C). Peak area is a measure of the relative content of components in a material. The calculation of the relative content of polyethylene and polypropylene in all studied samples of the composition details was carried out. It was found that, on average, the relative calculated value of the polyethylene content in the composition varies from 20 to 25% of the mass, and the relative calculated value of the polypropylene content in the composition is from 74 to 82% by mass. It is shown that the lack of quality of the material can be established at the stage of input control. A method for evaluating the composition of the material of products is proposed, which indicates the difference between batches of products of automotive components and can serve as a basis for accepting or rejecting this lot by conducting a sufficiently short-term DSC analysis and calculating the relative content of polyolefins in the composition.