Popular Science: What are the raw materials for early-strength superplasticizers synthesized from?

What are the raw materials for early-strength superplasticizers made of? Everyone in the industry and grassroots workers are very curious. Yes, the editor of Qingdao Dingchang New Materials Co., Ltd. learned from a person who has been engaged in the concrete industry for decades:

Synthetic raw materials of early strength water reducing agent:

　( 1) Unsaturated acids: maleic acid, maleic anhydride, acrylic acid, methacrylic acid, etc.;

(2) Polyalkenyl macromonomers: polyalkenyl hydrocarbons, ethers, alcohols, etc.;

　(3) Polystyrene sulfonate or ester;

　(4)(meth)acrylic Salt, ester, benzene, acrylamide, etc.

Raw materials used to synthesize early-strength superplasticizer

Allyl alcohol polyoxyethylene ether (APEG), chemical structural formula: CH2=CHCH20 (CH2CH20)n H):

Ammonium persulfate (AI'S), molecular formula (NI-I4) 2S208, molecular weight 228.2, properties: white crystal, with certain oxidizing properties.

Potassium persulfate, molecular formula K2S208, molecular weight 270.32, inorganic compound, white crystal, odorless, deliquescent Sexual, combustion-supporting, stimulating.

Maleic anhydride ( ), molecular formula CHCOOCOCH;

　Molecular weight 98.06, colorless needle-shaped crystals.

Sodium allyl sulfonate (SAS), molecular weight 144.1; structural formula: CH2=CH—CH2- SO3Na; white solid powder.

Sodium methacrylate sulfonate (SMAS), industrial product, molecular structure formula: CH2C(CH3)CH2SO3Na , molecular weight 158.15, white flaky crystals.

Methacrylic acid (MAA), analytically pure, colorless liquid, molecular formula: C4H60, molecular weight 86.09, Freezing point ≥12.5"C.

Acrylic acid (from), molecular formula ��C3H402, molecular weight 72.06, content ≥99.0%, colorless liquid, pungent odor

Early Strong Synthesis method of water-reducing agent: Mix acrylic acid, sodium methacrylate sulfonate, ammonium persulfate, and polyoxyethylene allyl ester macromonomer with deionized water to prepare an aqueous solution with a concentration of 20%. In a three-necked flask equipped with a stirrer, reflux condenser and thermometer, the monomer and initiator are added dropwise in batches. After the addition is completed, the reaction is maintained at 75°C for a certain period of time. After the reaction is completed, use a NaOH aqueous solution with a concentration of 20% to adjust the pH value to 7-8 to obtain a yellow or reddish-brown early-strength superplasticizer with a concentration of approximately 20%.

The main varieties of high-efficiency water reducing agents in my country are: naphthalene sulfonate formaldehyde condensate (naphthalene series), Sulfonated melamine formaldehyde condensate (melamine series), sulfamate series, aliphatic series and early-strength superplasticizer, etc.

Early-strength superplasticizer is the high-tech superplasticizer with the largest production volume and the most widely used in China ( Accounting for more than 70% of the amount of water reducing agent), its characteristics are:

　a High water reduction rate (15%~25%), b does not entrain air, c has little effect on setting time, d has relatively good adaptability to cement and can be used in combination with various other admixtures, e is relatively cheap

Early-strength water-reducing agent Compared with other types of water-reducing agents, early-strength water-reducing agents not only have super-dispersing properties, but also can suppress The slump loss of concrete is currently the focus of research and development of water reducing agents at home and abroad. Early-strength superplasticizer has relatively good adaptability to different cements, and it is easier to exert its low viscosity and slump-maintaining properties at low water-cement ratios, so it has been promoted and applied rapidly in Europe and Japan. </p