Minimum end time policies for batchwise radical chain polymerization—III: The initiator addition policies

✍ Scribed by Show-an Chen; Nae-wen Huang

• Publisher: Elsevier Science
• Year: 1981
• Tongue: English
• Weight: 853 KB
• Volume: 36
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(81)80164-9

✦ Synopsis

For batchwise radical chain solution polymerization, the minimum end time problem is studied by considering the initiator concentration (or feed rate) and temperature as two control variables. The kinetic model used is based on a general mechanism and involving the gel effect. It is found that the optimal initiator addition policy is to make the rate of initiation con_stant an$ rate of conversion nearly constant throughout the entire process. This results in a small variation of X. and X, with time and therefore in a nearly constant polydispersity (about 1.6 for styreneltoulene system) in the absence of chain transfer agent. For isothermal case, the initiator concentration should remain constant; analytical expression for temperature and initiator concentration are obtained. For nonisothermal case with high conversion, the temperature increases to a maximum and then drops, while the initiator concentration progresses oppositely. Further calculation shows that the optimal initiator addition processes are more efficient than the optimal processes with one-charge of initiator. Experimental verifications on the isothermal initiator addition policies for the polymerizations of styreneltoluene system show promising.