Algorithm for Evaluation of the Molecular Characteristics of a Polymer Product under Conditions of Multipoint Control

Abstract

ntroduction. Under conditions of high demand for rubber products, continuous modernization of technological processes of continuous production is carried out. One of the tools to control the physical and chemical parameters of the resulting product is the technology of multipoint feeding of controlling impurities that can significantly affect the molecular characteristics of polymers. However, it is difficult to experimentally select the technology of multipoint feeding of controlling impurities to achieve the given molecular characteristics of polymers. Aim of the Article. To create a methodology that allows using the tools of model system description to carry out directed regulation and construction of the technological process to achieve a given molecular weight distribution. Materials and Methods. For more accurate mathematical modeling of polymer synthesis processes, two approaches to the model description of the system under study are considered: 1) Kinetic approach. In this case, the developed algorithm is based on the method of moments in combination with numerical methods for solving systems of ordinary differential equations that characterize the change in the material balance for each reaction component. When describing large-tonnage production, a modular principle is proposed, according to which the kinetics model is supplemented by hydrodynamic regularities that depend on the reactor type. 2) Statistical approach (Monte Carlo method). The algorithm for implementing the statistical approach is based on the probabilistic nature of elementary reactions. To describe the process in the reactor cascade, a systematic approach to the organization of calculations is proposed. Results. Using kinetic and statistical approaches new dependences of conversion and characteristic viscosity on polymerizer number were obtained, which showed satisfactory agreement with the values of the experimental results. Comparative analysis of calculated molecular-mass distribution curves of obtained product was carried out. The analysis confirms the significant influence of different modes of regulator feeding on molecular characteristics of polymer. Discussion and Conclusion. The analysis of the molecular chain structure of the copolymerization product under conditions of adding the third control point characterizes the decrease in rigidity and increase in elasticity of the resulting product, and the created digital evaluation tools allow by means of computational experiments to select optimal parameters of the regulator feeding in order to obtain polymers with a given molecular mass.

Keywords

• synthetic rubber
• polymer
• cascade of reactors
• mathematical modeling
• numerical methods
• molecular weight control