title: A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.
abstract: This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization.
authors.affiliation: State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China. xschai@scut.edu.cn
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Chai
authors.forename: Jin-Feng
authors.initials: JF
authors.lastname: Zhong
authors.forename: Hui-Chao
authors.initials: HC
authors.lastname: Hu
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D004655:Emulsions / Q000737:chemistry*; D007700:Kinetics; D020366:Methylmethacrylate / Q000737:chemistry; D008956:Models, Chemical; D058105:Polymerization; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D004655:Emulsions; D011108:Polymers; D020366:Methylmethacrylate