Synthesis, Performance Evaluation, and Adsorption-Dispersion Mechanism of Sulfonic Acid-Terminated Long Side Chain...

Area of Science:

• Materials Science
• Civil Engineering
• Polymer Chemistry

Background:

• Polycarboxylate superplasticizers (PCEs) are crucial for concrete workability.
• Long poly(ether) side chains in PCEs can lead to structural collapse, limiting their effectiveness.
• Developing novel PCE structures is essential for enhanced concrete admixture performance.

Purpose of the Study:

• To synthesize and evaluate sulfonic-terminated polycarboxylates (PCEPS) as advanced concrete admixtures.
• To investigate the impact of sulfonic acid terminations on PCE dispersion and stability in cementitious systems.
• To compare the performance of PCEPS with conventional carboxyl-terminated PCEs.

Main Methods:

• Synthesis of sulfonic-terminated polycarboxylates (PCEPS).
• Characterization of adsorption layer thickness (ALT) using techniques like ellipsometry.
• Evaluation of dispersion, clay tolerance, and slump retention in cementitious mixtures.
• Comparison with conventional polycarboxylate ether (PCEC) and carboxyl-terminated long side chain polycarboxylate (PCETA).

Main Results:

• PCEPS demonstrated significantly enhanced dispersion in cement compared to conventional PCEs.
• PCEPS-4000 exhibited a greater adsorption layer thickness (11.65 nm) than PCETA (7.93 nm).
• The introduction of sulfonic acid groups reduced structural collapse and improved side chain extension.

Conclusions:

• Sulfonic acid terminations effectively mitigate structural collapse in PCEs, leading to improved dispersion.
• PCEPS offer superior performance, including enhanced dispersion, clay tolerance, and slump retention.
• PCEPS represent a versatile and effective next-generation concrete admixture.