Heterogeneous iron(II)-chloride mediated radical polymerization of styrene
2009 (English)In: Journal of Molecular Catalysis A: Chemical, ISSN 1381-1169, Vol. 306, no 1-2, 69-76 p.Article in journal (Refereed) Published
In an attempt to perform atom transfer radical polymerization (ATRP) with a more environmentally friendly mediator, polymerization of styrene in the presence of iron(II)-chloride and EDTA was explored from a mechanistic point of view. The presence of EDTA, which normally can form a complex with FeCl2, had no influence on the polymerization results as both the mediator and EDTA were insoluble in the polymerization medium. A mechanism is suggested for the heterogeneous polymerization of styrene mediated by iron (II)-chloride in p-xylene at 50 °C. Varying the mediator amount more than 10-fold revealed that the rate limiting step at low mediator amounts was the adsorption of the initiator or dormant polymer to the mediator surface, whereas at higher mediator amounts, the rate limiting step was instead the activation step in the ATRP equilibrium. The mechanism changed to free radical polymerization in solution at a certain conversion, resulting in lower apparent rate constant and an increased amount of transfer and termination reactions. Chain extension with MMA showed that a significant proportion of the polymer chain ends were active also at high conversions.
Place, publisher, year, edition, pages
2009. Vol. 306, no 1-2, 69-76 p.
Atom transfer radical polymerization (ATRP), Heterogeneous, Iron chloride, Kinetics, Polystyrene
IdentifiersURN: urn:nbn:se:kth:diva-18528DOI: 10.1016/j.molcata.2009.02.024ISI: 000267084900011ScopusID: 2-s2.0-67349222833OAI: oai:DiVA.org:kth-18528DiVA: diva2:336575
QC 201005252010-08-052010-08-052011-04-06Bibliographically approved