Kinetic modeling of the aqueous copolymerization of acrylamide with N,N'- methylenebisacrylamide

Kinetic Modeling of the Aqueous Copolymerization of Acrylamide with N,N’-Methylenebisacrylamide Virgínia Pinto,1 Miguel Gonçalves,1 Rolando Dias,1 Mário Rui Costa2 1LSRE-Polytechnic Institute of Bragança, Portugal, Email: [email protected] 2LSRE-FEUP, Porto, Portugal, Email: [email protected] Polyacrylamide (PAAm) and related water-soluble copolymers find important applications in different fields such as petroleum production, environment, papermaking or agriculture. On other hand, polyacrylamide hydrogels are commonly used in electrophoresis and many bioseparations. This research reports kinetic modeling studies concerning the synthesis of PAAm and acrylamide/N,N’-methylenebisacrylamide (AAm/BAAm) hydrogels, in a 2.5 L batch reactor, considering aqueous solution and water in oil inverse suspension polymerizations. Isothermal experimental runs are performed at different temperatures in the range 20 to 60 C using ammonium persulfate (APS) as initiator and N,N,N’,N’-tetramethylethylenediamine (TEMED) as accelerator (at lower temperatures). Different values of the initial mole faction of BAAm in the initial monomer mixture are also considered in these experiments. Information concerning the dynamics of the building process of such materials is obtained using in-line FTIR-ATR monitoring and off-line SEC/RI/MALLS analysis of samples collected at different reaction time. Experimental measurements are complemented with theoretical studies in the framework of a general kinetic approach based upon population balances equations of generating functions.[1] Formation of hydrogels is affected by non-idealities of the crosslinking process (e.g. different reactivity of vinyl groups or cyclization) with important deleterious effect on the end use properties of such materials.[2,3] Such complexities makes the prediction of physical properties of hydrogels from the synthesis conditions an open problem. With this research is expected to contribute for the elucidation of some of these issues. [1] M.R.P.F.N. Costa, R.C.S. Dias, Chem. Eng. Sci. 2005, 60, 423. [2] M.Y. Kizilay, O. Okay, Macromolecules 2003, 36, 6856. [3] S. Abdurrahmanoglu, O. Okay, Macromolecules 2008, 41, 7759.