Kinetic studies on styrene-divinylbenzene copolymerization by suspension technique

Kinetic studies on styrene and divinylbenzene (DVB) copolymerization by the suspension technique in a toluene diluent initiated by benzoyl peroxide ar e reported. Evaluation of the important reaction parameters is carried out. The crosslinked styrene-DVB copolymers can absorb toluene to a maximum swe lling ratio of 17. The absorption/desorption took place instantaneously and reached the maximum value within 10 min, and it could be repeated many tim es, yet gave the consistent result. Rate equations evaluated by both integr al and differential methods are investigated. High monomer orders of 1.5-2. 3 were obtained. The activation energy for the polymerization was about 40 kcal/mol(-1). Autoacceleration was found even at low conversions. The accel eration was influenced by both monomer, crosslinker, and initiator concentr ations. The integral and differential methods for the rate evaluation were compared, and the relationship between the rate equation and polymerization behavior was elucidated. The kinetic orders determined for this copolymeri zation show considerable deviation. (C) 2001 John Wiley & Sons, Inc.