Molecular Weight Distribution Control in Continuous `LivingL Polymerizations through Periodic Operation of the Monomer Feed

MEIRA, G. R.; JOHNSON, A. F.

POLYMER ENGINEERING AND SCIENCE

Año: 1981 vol. 21 p. 415 - 423

0032-3888

The main objective of the work is to explore the problem of producing polymers of any desired molecular weight distribution (MWD) in isothermal, solution, "living", anionic polymerizations carried out in continuous tubular reactors. For this purpose, a novel control scheme was designed and implemented, which involves the periodic operation of the monomer solution flow rate, with the flow profile automatically derived from the required MWD and other data. For experimental validation, a polymerization rig was especially built that included a process computer and an automatic gel permeation chromatograph. The chromatograph permitted the measurement of the MWD of the reactor effluent in a matter of minutes and the process computer was employed to implement the control policies and to perform the chromatograph data acquisition and reduction. In spite of the practical problems encountered, experiments showed at least a semi-quantitative validity of the method.