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

The goal in this study is to shed light on the ambiguous procedure of making AAm/AAc copolymers for polymer flooding applications for enhanced oil recovery (EOR). Despite the extensive use of these copolymers in polymer flooding, a well‐established recipe for the required desirable properties of AAm/AAc copolymers does not exist in the literature. Therefore, the knowledge from copolymerization kinetics and copolymer structure/property relationships is implemented to tailor‐make copolymers for polymer flooding. The detailed knowledge of the copolymerization kinetics enables to design copolymers with desirable properties, such as high molecular weight, high AAm content in the copolymer, and random distribution of anionic charges along the copolymer chain. Moreover, rheological properties show that copolymers with higher AAc content in the copolymer have higher solution viscosity and elasticity, both of which are desirable properties. In general, the main factors that should be considered when designing a polymer for polymer flooding for EOR applications are described.

This article presents the correlation between rheology and morphology of nanocomposite foams of low‐density polyethylene (LDPE), ethylene vinyl acetate (EVA), and their blends. LDPE/EVA nanocomposites were prepared via melt mixing and then foamed using batch foaming method. To assess the rheological behavior of polymer melts, frequency sweep and creep recovery tests were done. Morphology of the samples was also studied by scanning electron microscopy and X‐ray diffraction. The results showed that with increase in clay content, storage modulus, complex and zero shear viscosities will be increased, which affect the foam morphology. In addition, elasticity plays an important role in foaming process, in a way that samples with more elasticity percentage have the highest cell density and the lowest cell size. POLYM. COMPOS., 31:1808–1816, 2010. © 2010 Society of Plastics Engineers.