Thermal properties of hydrophobically modified methacrylic acid–ethyl acrylate copolymer solutions

Abstract

ABSTRACT:The thermal behavior of a water-soluble associating polymer system, hydrophobically modified alkalisoluble emulsion (HASE) polymer, was investigated. This polymer contains a methacrylic acid-ethyl acrylate copolymer backbone with 1 mol % of pendant hydrophobic groups grafted to it. The thermal behavior of the HASE polymer exhibits different trends compared to the hydrophobic ethoxylated urethane (HEUR) system. The lifetime of the hydrophobic junction of the HASE polymer increases with temperature due to the increase in the entropy of the system. However, the structural relaxation time decreases with temperature, caused by the enhanced Brownian dynamics of polymer chains. The relaxation behavior of HASE polymers is either governed by the lifetime of the hydrophobic junction, the structural relaxation time, or a combination of both, depending on the degree of network formation and temperature. Temperature studies indicated that the transient network theory proposed by Tanaka and Edwards is inadequate for describing the activation process of hydrophobic junctions in the HASE associative polymer.

Rheological properties of hydrophobically modified polyelectrolyte systems: Concentration effects

“…3,11,15 Under shear, the presence of these mechanically active hydrophobic junctions hinders and delays the complete breakdown of the transient network structure, which slows down the destruction of the polymeric network. 12,31 It is evident from Figure 2 that at higher polymer concentration, the onset of shear thinning behavior occurs at lower shear rates. With increasing polymer concentration, the formations of higher number of mechanically active hydrophobic junctions and aggregation number in the network are expected to retard the relaxation behavior of the polymeric chains.…”

Rheology Behavior of Hydrophobically Modified Poly(acrylic acid) with Twin-Tailed Pendant in Water—Ethylene Glycol Mixture

“…As the temperature was decreased to −10 • C, the number density of network junctions increased as did the network relaxation time. [11] It should be noticed that the dynamic data in the measured frequency range of 0.1-100 rad/s could not be time-temperature superposed using only horizontal shift factors. It is clear that the HMPA with twin-tailed pendant side groups can help to maintain a good network structure for viscosity enhancement at low temperature.…”

Relaxation behavior of hydrophobically modified polyelectrolyte solution under various deformations

“…Hydrophobically modified alkali-soluble (HASE) associative polymer has receive increasing attentions in recent years [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. Most of these studies focused on describing the microstructure and the behavior of HASE in the presence of surfactants.…”