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Poly(acrylamide-co-octylphenol polyoxyethylene (10) acrylate) hydrophobic association hydrogels, which is abbreviated to poly(AM-co-OP10/AC) HA-gels, were prepared through micellar copolymerization of acrylamide (AM) and a small amount of octylphenol polyoxyethylene (10) acrylate (OP10/AC) in the presence or absence of sodium dodecyl sulfate (SDS). For poly(AM-co-OP10/AC) HA-gels, formation mechanism was discussed in detail, which can reasonably explain the reason that tensile mechanical properties of the hydrogels (containing SDS) are much higher than those of the hydrogels (not containing SDS). In addition, according to the tensile experimental results of poly(AM-co-OP10/AC) HA-gels, the effect of composition content in the initial solutions on tensile mechanical properties was investigated in detail. The results clearly indicate tensile strength, elastic modulus and elongations for poly(AM-co-OP10/AC) HA-gels strongly depended on composition content in the initial solutions. [ABSTRACT FROM PUBLISHER]

Hydrophobic association hydrogels (HA-gels) were prepared through micellar copolymerization of acrylamide (AM) and a small amount of octylphenol polyoxyethylene acrylate (OP-IO-AC) in an aqueous solution containing sodium dodecyl sulfate (SDS). For the P(AM/OP-10-AC) HA-gels, the effect of crosslinking method, synthesis temperature, mineral salt (NaCl) and swelling on their tensile mechanical properties was investigated in detail. The experimental results show that crosslinking method, synthesis temperature, NaCl and swelling powerfully influenced tensile mechanical properties of the P(AM/OP-10-AC) HA-gels. In addition, according to the tensile experimental results of the P(AM/OP-10-AC) HA-gels swollen, an effective crosslinking density change model is proposed. The effect of swelling on tensile mechanical properties of the P(AM/OP-10-AC) HA-gels was discussed on the basis of the model. [ABSTRACT FROM AUTHOR]

A micelle-forming polymerizable surfactant monomer, octylphenol polyoxyethylene acrylate (OP-10-AC), was synthesized, and then OP-10-AC was copolymerized with acrylamide (AM) to form nonionic hydrophobically modified polyacrylamide P(AM/OP-10-AC) through micellar copolymerization. In the absence of surfactants, it was investigated in detail that the effect of mineral salts and temperature on steady rheological properties of P(AM/OP-10-AC) solutions and the effect of concentrations on reduced viscosity of P(AM/OP-10-AC) in a dilute solution. The results indicate that concentrations of the copolymer, mineral salts and temperature had a strong influence on shear viscosity of P(AM/OP-10-AC) solutions, and the trend of reduced viscosity of P(AM/OP-10-AC) solutions was distinctly different from polyacrylamide with increasing concentrations of testing solutions. In addition, it was also investigated that stress-relaxation behavior of an aqueous solution of P(AM/OP-10-AC)/KCl. As a result, a stress-relaxation model of the copolymer solutions was proposed, which can further verify the correctness of the conclusion on stress-relaxation behavior of hydrophobic association hydrogels in the paper reported previously. [ABSTRACT FROM AUTHOR]

Hydrophobic association hydrogels (HA-gels) with high mechanical strength, self-healing capability and transparency were successfully prepared by micellar copolymerization, and associated micelles acted as physical crosslinking points in the network structure of HA-gels. In this study, the swelling behavior of HA-gels in distilled water at room temperature was investigated. With increasing the content of hydrophobic monomer in the HA-gels, the swelling degree of HA-gels decreased. According to the results of swelling experiments, a swelling model of HA-gels was proposed, which could reasonably explain the swelling behavior of HA-gels. Moreover, the effect of other test conditions on the swelling behavior of HA-gels was also investigated, such as temperature, sodium dodecyl sulfate (SDS), pH and NaCl. These results indicate that the swelling behavior of HA-gels could be strongly influenced under the conditions mentioned above. [ABSTRACT FROM AUTHOR]

Hydrophobic association hydrogels (HA-gels) were prepared through micellar copolymerizationof acrylamide (AM) and a small amount of octyl phenol polyethoxy ether acrylate (OP-4-AC) in an aqueous solution containing sodium dodecyl sulfate (SDS) at 50°C. The resulting HA-gels exhibited excellent mechanical properties and transparency. However, the most striking properties were that HA-gels possessed the capability of self-healing. The mechanical properties of HA-gels were investigated by uniaxial stretching. The results showed that the mechanical properties of HA-gels could be varied greatly by changing OP-4-AC content in the range of OP-4-AC used. On the basis of the rubber elastic theory and using uniaxial stretching data, the effective network chain density and the average distance between the cross-linking points were calculated for HA-gels. For tensile measurements of altering crosshead speed, the modulus of HA-gels increased sharply with increasing crosshead speed. The stress-relaxation behavior of HA-gels consisted of two stages. Similar to rubbery, HA-gels exhibited obvious thermoelastic behavior and also showed a good rubberlike elastic property. [ABSTRACT FROM AUTHOR]