Photocatalytic Degradation of Poly(Acrylamide-co-acrylic Acid)

Abstract

Poly(acrylamide-co-acrylic acid) copolymers of different compositions were synthesized and characterized. The copolymers were statistical with a relatively high percentage of acrylamide units, as determined by (13)C NMR. Reactivity ratios calculated by the Finemann-Ross and Kelen-Tudos methods showed that the copolymers were random with a reactivity ratio of r AM = 3.76 and r AA = 0.28. The photolytic and photocatalytic degradation of the copolymers and the homopolymers was conducted in the presence of combustion-synthesized nano anatase titania. The degradation of the copolymer in the presence of combustion-synthesized titania was significantly higher than that observed in the presence of commercial titania, Degussa P-25. The degradation was modeled by using continuous distribution kinetics by following the time evolution of molecular weight distribution. The degradation follows a two step mechanism, wherein the rapid first step comprises the scission of weak acrylic acid units along the chain which is followed by the breakage of relatively strong acrylamide units. The rate constants for the weak and strong links follow a linear trend with the percentage of acrylic acid and acrylamide in the copolymer, respectively. This linear variation can be correlated with a similar trend observed for the activation energies obtained for the pyrolytic degradation of the polymers.

Photo, thermal, and ultrasonic degradation of EGDMA‐crosslinked poly(acrylic acid‐co‐sodium acrylate‐co‐acrylamide) superabsorbents

“…As the AM content increased from 20 to 80%, the time scale of the first region increased, indicating improvement in the UV resistance of the SAPs. The improvement in the SAPs UV resistance with increasing AM content conforms with the study of photocatalytic degradation of poly(acrylamide‐ co ‐acrylic acid) 37. There is 1.52–2.73 times increment in the swelling capacity of the SAPs in the first region, indicating that the crosslinking agent concentration used is more than the optimum resulting in a dense network and still higher swelling capacities can be obtained by lower crosslinking agent concentrations.…”

“…The improvement in the SAPs UV resistance with increasing AM content conforms with the study of photocatalytic degradation of poly(acrylamide-coacrylic acid). 37 There is 1.52-2.73 times increment in the swelling capacity of the SAPs in the first region, indicating that the crosslinking agent concentration used is more than the optimum resulting in a dense network and still higher swelling capacities can be obtained by lower crosslinking agent concentrations. Thus, the photodegradation of SAPs can be qualitatively used to characterize the crosslink density of SAPs.…”

Delayed Crosslinking Amphiphilic Polymer Gel System with Adjustable Gelation Time Based on Competitive Inclusion Method

“…The viscosity enhancement of HPAM is mainly up to the expansion of solvated chains, owing to the repulsion of carboxylate groups. HPAM shows poor salt resistance, temperature resistance, and shear resistance performance, which hindered its application in high temperature and high salinity reservoirs [15,16,17,18]. As a result, many polymers are developed and applied in high temperature and high salinity reservoirs, such as modified xanthan [19], amphiphilic polymer like hydrophobically modified polyacrylamides (HMPAM), and so on.…”

Heterogeneous catalytic degradation of polyacrylamide solution

“…Many methods had been developed for treating PAM, including ultrasonic degradation (Vijayalakshmi et al, 2005;Yen, 2003), pulsed laser degradation (Vijayalashmi et al, 2005), thermal degradation (Yang, 1998;Yang, 2000), photo-catalytic degradation (Vinu et al, 2008) and so on. However, some of these methods are too expensive to achieve industrialization, and it was found that the degradation ratio of PAM in aqueous solution was slow by using physical and biological methods.…”