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
