Computation of molecular weight distributions for free radical polymerization systems

✍ Scribed by Uwe Budde; Michael Wulkow

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 988 KB
• Volume: 46
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(91)80010-v

✦ Synopsis

Modeling of free radical polymerization leads to very large and usually stiff systems of ordinary differential equations which cannot he solved directly in an efficient way. This paper presents the application of a new approach called the discrete Galerkin method to a realistic example-the polymerization of methyl methacrylate (MMA). The method is characterized by a Galerkin approximation on the basis of orthogonal polynomials of a discrete variable which represents the polymer degree. It allows the efficient computation of solutions of complete kinetic schemes with time-or moment-dependent reaction coefficients by reducing the complexity to a few differential equations. The approximation error can bc controlled by an error estimation. In the case of MMA polymerization a reduction ofcomputational effort by a factor of about 25 compared to a standard method can be obtained for the quasi-steady-state approximation of the model. In addition solutions of the un-stationary kinetic scheme can be easily computed.