- Efficient concrete foam stabilizer and preparation method thereof
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The invention discloses an efficient concrete foam stabilizer and a preparation method thereof, according to the efficient foam stabilizer, polyol is subjected to an esterification reaction to form ester bonds, and the ester bonds are connected with amphiphilic side chains, and the number of the amphiphilic side chains is 3-7; one end of the amphiphilic side chain is a hydrophobic chain segment, and the other end of the amphiphilic side chain is a hydrophilic unit; wherein the hydrophobic chain segment is an alkyl chain (R) with 8-14 carbons, and the hydrophilic unit is 2-10 ethylene oxide units. The efficient concrete foam stabilizer is a multi-chain type surfactant, and the multi-chain type surfactant is hydrolyzed under the alkaline condition to release an air-entraining type surfactant. The efficient concrete foam stabilizer has an excellent effect of stabilizing the air content of concrete, meanwhile, hardened concrete has a better pore structure, and the hardening strength of the concrete cannot be greatly influenced.
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Paragraph 0027; 0052-0053
(2021/07/17)
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- Combinatorial synthesis of PEG oligomer libraries
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A simple chain-extending approach was established for the scale-up of the monoprotected monodisperse PEG diol materials. Reactions of THP-(OCH2CH2)n—OMs (n=4, 8, 12) with a large excess of commercially available H—(OCH2CH2)n—OH (n=1-4) under basic conditions led to THP-(OCH2CH2)n—OH (n=5-15). Similarly, Me-(OCH2CH2)n—OH (n=4-11, 13) were prepared from Me-(OCH2CH2)n—OMs (n=3, 7, 11). For the chain elongation steps, 40-80% yields were achieved through extraction purification. PEG oligomer libraries I and II were generated in 50-95% overall yields by alkylation or acylation of THP-(OCH2CH2)n—OH (n=1-15) followed by deprotection. Alkylation of Me-(OCH2CH2)n—OH (n=1-11, 13) with X—(CH2)m—CO2R (X=Br or OMs) and subsequent hydrolysis led to PEG oligomer library III in 30-60% overall yields. Combinatorial purification techniques were adapted to the larger-scale library synthesis. A total of 498 compounds, each with a weight of 2-5 g and a minimum purity of 90%, were synthesized.
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Page/Page column 10
(2010/02/15)
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