Acrylamide (AAm)/acrylic acid (AAc) copolymer application performance is tied to copolymer properties, which in turn are related to the kinetics of the copolymerization. A systematic study has been conducted to investigate the effect of reaction factors such as total monomer concentration and solution pH on polymerization kinetics and copolymer microstructure. To study the effect of these factors, reliable reactivity ratios were estimated first. The trends in copolymer composition, molecular weight, sequence length distribution, and triad fractions were subsequently examined. Having a better understanding of kinetic profiles is needed in order to manipulate influential factors for tailoring AAm/AAc copolymer properties for the desired application.

The ionic strength (IS) of polyelectrolyte solutions plays an important role in influencing reaction kinetics. The largely unstudied effect of IS on monomer reactivity ratios and copolymerization rates of acrylamide (AAm) and acrylic acid (AAc), in the form of sodium acrylate (NaAc), is investigated. Salt addition affects the nature of overall charges of the polyelectrolyte solution and diminishes the electrostatic repulsions between reacting chains. Therefore, changing the IS of the solution by incorporating salts affect not only the point estimates of the monomer reactivity ratios but also the overall behavior of the copolymerization (with a transition to azeotropic behavior). Experimental results on copolymerization rates confirm the observed trends in reactivity ratio behavior. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40949.

Reactivity ratios for the important acrylamide (AAm)/acrylic acid (AAc) copolymerization system exhibit considerable scatter in previously published literature, and therefore, there is a need for more definitive values for these reactivity ratios. An appropriate methodology, based on the error‐in‐variables‐model (EVM) framework along with a direct numerical integration procedure, is applied in order to determine reliable reactivity ratios. The reliability of the results is confirmed with extensive and independent replication. Furthermore, via an EVM‐based criterion for the design of experiments using mechanistic models, optimal feed compositions are calculated, and from these optimal reactivity ratios are estimated for the first time (rAAm = 1.33 and rAAc = 0.23) based on information from the full conversion range. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4819–4827

An experimental study of the bulk free radical polymerization of ethyl acrylate (EA) initiated by 2,2'-azoisobutyronitrile (AIBN) was conducted. The experiments were carried out based on a factorial design with replicates. The reaction variables investigated were initiator concentration, temperature and chain transfer agent (CTA) concentration (primary octanethiol). The results obtained were used to develop and test a simulation model for EA homopolymerization.

ABSTRACT:The quantitative hydrogenation of cis-1,4-poly-(isoprene) (CPIP) provides an easy entry to the alternating copolymer of ethylene-propylene, which is difficult to prepare by conventional polymerization. The homogeneous hydrogenation of CPIP, in the presence of OsHCl(CO)(O 2 )(PCy 3 ) 2 as catalyst, has been studied by monitoring the amount of hydrogen consumed during the reaction. The final degree of olefin conversion measured by computer-controlled gas uptake apparatus was confirmed by infrared spectroscopy and 1 H nuclear magnetic resonance analysis. Kinetic experiments for CPIP hydrogenation in toluene solvent indicate that the hydrogenation rate is first order with respect to catalyst and carboncarbon double bond concentration. A second-order dependence on hydrogen concentration for low values and a zeroorder dependence for higher values of the hydrogen concentration was observed. The apparent activation energy for the hydrogenation of CPIP over the temperature range of 115-140°C was 109.3 kJ/mole. Mechanistic aspects of this catalytic process are discussed.