Acrylamide polymerization monitoring

Most studies have dealt either with the free radical polymerization of hydrophobic monomers—e.g., styrene [56-89], methyl methacrylate (MMA) [68,73,74,84,86,90-93] or derivatives [2,94,97], and butyl acrylate (BA) [98-100]—within the oily core of O/W microemulsions or with the polymerization of water-soluble monomers such as acrylamide (AM) within the aqueous core of W/O microemulsions [101-123]. In the latter case, the monomer is a powder that has to first be dissolved in water (1 1 mass ratio) so that the resulting polymer particles are swollen by water, in contrast with O/W latex particles, where the polymer is in the bulk state. The polymerization can be initiated thermally, photochemically, or under )>-radiolysis. The possibility of using a coulometric initiation for acrylamide polymerization in AOT systems was also reported [120]. Besides the conventional dilatometric and gravimetric techniques, the polymerization kinetics was monitored by Raman spectroscopy [73,74], pulsed UV laser source [72,78], the rotating sector technique [105,106], calorimetry, and internal reflectance spectroscopy [95]. 

Monitoring Acrylamide Polymerization Time-dependent signatures for conversion, reduced viscosity, and molecular weight during continuous online monitoring of acrylanude polymerization under a variety of temperature, and initiator conditions were compared in Reference [3]. 

Giz A, Qatalgil-Giz H, Alb AM, Brousseau J-L, Reed WF. Kinetics and mechanisms of acrylamide polymerization from absolute, online monitoring of polymerization reactions. Macromolecules 2001 34 1180-1191. 

Summary Films of polyacrylic acid hydrogels were produced on a conducting substrate by means of electrochemically Initiated polymerization (EIP). An electrochemical quartz crystal microbalance was used to monitor film growth In situ. Homopolymer and copolymer films of polyacrylic acid and poly-N-isopropyl-acrylamide were characterized by FTIR spectroscopy. The degree of swelling of these films could be tuned via the pH. 

Potassium persulfate-initiated polymerization of acrylamide (AM) in water was chosen as a case study for chain transfer reactions monitored by ACOMP [7]. Chain transfer properties of ethanol (EtOH) and 2-propanol (PrOH) were investigated. 

Various methods have been used to analyze aliquots from reactions [27, 28], Online measurements by dilatometry have also been reported [29], A significant advance in this field was the adaptation of ACOMP as a means for monitoring conversion and measures of polymer molar mass during the inverse emulsion polymerization of acrylamide, in order to understand both reaction kinetics and mechanisms and, potentially, to control them during the reaction [30],... 

As shown in Chapter 1, the initiation step in free radical polymerization can be rate limited either by decomposition of the initiator or diffusion-controlled initiation of decomposed radicals with the first monomer. Automatic continuous online monitoring of polymerization reactions (ACOMP) was used to experimentally observe the crossover between decomposition control and diffusion control of the initiation step. The crossover was observed both among potassium persulfate initiated acrylamide (Am) free radical polymerization reactions at different concentrations of Am and in single reactions. There is no appreciable chain transfer in this particular polymerization. 

---