A novel high-temperature resistant superabsorbent was prepared by solution polymerization of partially neutralized acrylic acid (AA), using triallylammonium chloride as crosslinker, potassium persulfate as initiator. The factors that influence the water-absorbing capacity at 25 and 200°C such as mass concentration of monomer, mass ratio of crosslinker to AA, mass ratio of initiator to AA, and neutralization degree were investigated. The structure of the superabsorbent was characterized by Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy. The optimum conditions were obtained and the swelling ratios in distilled water and 1 wt % of NaCl solution could reach 841 and 74 g/g at 300°C, respectively. The superabsorbent also showed high swelling rate and good salt resistance. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41243.

A novel high-temperature resistant superabsorbent polymer (SAP) with a temperature switch to control its water absorbency was prepared through solution polymerization of acrylamide (AM), using N,N-methylenebisacrylamide (NMBA) and tetraallylammonium chloride (TAAC) as crosslinking agents. The SAPs were structurally characterized by Fourier transform infrared (FTIR) spectroscopy and energy dispersive X-ray spectroscopy (EDX). The factors that influence the water absorbency such as total crosslinker concentration, molar ratio of NMBA to TAAC and temperature were investigated. The SAP with optimized crosslinker concentration showed a swelling ratio less than 10 g/g at 25°C, and drastically enhanced water absorption capacity (190 g/g) at 300°C. The water absorption characteristics can be tuned by varying the temperature. Swelling experimental results combined with crosslinking density study and morphology observation by scanning electron microscopy (SEM) clearly demonstrated that the hydrolysis of amide bonds on NMBA played a critical role in creating these previously unreported SAPs, and that the use of TAAC with an appropriate amount rendered the SAPs high-temperature resistance. This kind of SAPs has high application potentials as plugging material for steam breakthrough and channeling in heavy oil reservoirs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42067.

A high-temperature (200°C)-resistant polymer gel system was developed from partially hydrolyzed polyacrylamide (HPAM), chromium lactate (CrL), and water-soluble phenol/formaldehyde resin (WPF) mixed cross-linkers. Rheological measurements indicated that the gelation process of the gel system could be divided into four successive steps: induction, first cross-linking with metal cross-linker, secondary cross-linking with organic cross-linker, and stabilization. Effects of various parameters that affect the gelation time and gel strength including polymer concentration, cross-linker concentration, salinity, pH, and the gelation temperature were evaluated. Gelant formulated with 0.5 wt % HPAM, 0.1 wt % CrL, and 0.9 wt % WPF and treated at 80°C for 48 h showed sufficient gelation time, high rigidity, and good thermal stability. Morphology observation by scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed that the gel had compact network microstructure. A cross-linking mechanism for the gel system was proposed based on the gelation process and experimental results. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42261.