3-Mercaptopropionic Acid (3-MPA) as Critical Raw Material for Polycarboxylate Superplasticizer (PCE) Synthesis
1. Product Positioning
Mercaptopropionic acid (MPA) serves as the essential chain transfer agent in polycarboxylate-based superplasticizer (PCE) production, directly influencing dispersibility and slump retention through molecular weight distribution control and terminal group modification.
2. Key Specifications (PCE-Grade)
| Parameter | Technical Standard | Impact on PCE Performance |
|---|---|---|
| Purity | ≥99.5% | Minimizes side reactions, improves conversion rate |
| Moisture | ≤0.3% | Prevents esterification inhibition |
| Disulfide content | ≤0.1% | Ensures chain transfer efficiency ≥92% |
| Fe ion content | ≤5ppm | Avoids polymerization system discoloration |
3. Three Critical Functions in PCE Synthesis
Molecular Weight Control
Terminates radical chain growth via -SH group to maintain ideal PCE MW (20,000-50,000 Da)
Typical dosage: 0.8-1.5 mol% of total monomers
Terminal Group Modification
Carboxyl terminals enhance cement particle adsorption (initial fluidity ≥260mm @5min)
Structural Stability
Suppresses branching reactions to preserve optimal "comb-like" structure (side chain density ≥85%)
4. Process Application Guidelines
Dosing Method Optimization
Recommended drip feeding (synchronized with acrylic acid) to prevent broad MW distribution
Temperature Control
Optimal reaction at 60-65°C (>70°C risks -SH oxidation deactivation)
Compatible Systems
Suggested molar ratio with V-501 (initiator): 1:1.2-1.5
3-MPA vs Other Mercapto Chain
How to Select a Reliable 3-Mer
How Does 3-MPA Control Molecul
3-Mercaptopropionic Acid as a