Synthesis Process of Polycarboxylate Superplasticizer Mother Liquid

**Synthesis Process of Polycarboxylate Superplasticizer Mother Liquid**

**1. Esterification Reaction (Macromonomer Preparation)**

The initial stage involves an esterification reaction to synthesize macromonomers. The detailed procedure includes:

- Melting polyethylene glycol (PEG) in a water bath before transferring to the reaction vessel

- Adding methacrylic acid along with a minor additive (a 5:1 mixture of hydroquinone and phenothiazine)

- Gradually heating the mixture to 90°C

- Introducing concentrated sulfuric acid as catalyst

- Further elevating temperature to 120°C and maintaining for 4.5 hours

- Conducting nitrogen purging for 2 hours (4 nitrogen bottles total, at 30-minute intervals) to ensure reaction purity

- The resulting product (polyethylene glycol monomethacrylate/water mixture) undergoes vacuum distillation and dehydration for complete acidification

**2. Polymerization Reaction**

The aqueous solution polymerization process using ammonium persulfate initiation involves:

*Preparation:*

- Metering esterification product (PEG monomethacrylate), acrylic acid, and molecular weight regulator (dodecyl mercaptan)

- Mixing with deionized water in dosing tank A

- Preparing ammonium persulfate solution in deionized water (dosing tank B)

*Reaction Conditions:*

- Heating reactor to 85°C with deionized water

- Simultaneous dosing from tanks A (3 hours) and B (3.5 hours)

- Maintaining post-dosing temperature at 90±2°C for 1.5 hours

**3. Neutralization Reaction**

To neutralize residual sulfuric acid catalyst:

- Cooling polymer below 50°C

- Gradually adding soda ash with continuous stirring

- Adjusting pH to ~7

- Final product: Polycarboxylate superplasticizer mother liquid

**Product Characteristics:**

- Excellent water reduction and strength enhancement

- Superior workability with minimal slump loss

- Low shrinkage characteristics

- Particularly suitable for high-strength performance concrete

**Process Advantages:**

- Simplified esterification with short production cycle

- Terminal unsaturated double bonds enable direct polymerization

- Cost-effective production

- Capability for high-concentration mother liquid production

- Broad applicability with outstanding performance

This optimized synthesis method has gained increasing attention due to its efficiency and the superior quality of the resulting polycarboxylate superplasticizer.

Tags: Polycarboxylate Superplasticizer, Polycarboxylate, PCE