A kind of preparation method of temperature-responsive comb structure polycarboxylic acid

Abstract

The invention relates to a preparation method of a temperature responsive comb-like structured polycarboxylic acid. By using acrylic ester, a temperature responsive monomer and the like as raw materials, a polycarboxylic acid material is prepared through steps of autopolymerization, graft copolymerization and hydrolysis. The preparation method comprises the following specific steps: acrylic ester,which is used as a reaction monomer, undergoes polymerization under the action of an initiator and a chain transfer agent to generate polyacrylate with controlled molecular weight; then, polyacrylateand the temperature responsive monomer are subjected to graft copolymerization to obtain a graft copolymer with the acrylic polymer as the a main chain and the temperature responsive polymer as a side chain; and finally, the graft copolymer undergoes hydrolysis to prepare the comb-like structured polycarboxylic acid with polyacrylic acid as the main chain and the temperature responsive polymer asthe side chain. By main chain polymerization before side chain grafting, polycarboxylic acid with the intelligent responsive side chain is successfully designed and synthesized. The reaction processis convenient and controllable, and is energy-saving and environmentally friendly. The product shows excellent temperature responsive behavior and multi-effects of inhibiting shrinkage of cement mortar, and has good market prospects and application value.

Description

technical field

[0001] The invention relates to the technical field of a temperature-responsive polycarboxylic acid for cement concrete, in particular to a comb-shaped polycarboxylic acid material synthesized by self-polymerization of an acrylic ester monomer and then grafted with a temperature-responsive monomer, followed by hydrolysis specific preparation method. Background technique

[0002] The rapid development of high-performance concrete has led to higher and higher requirements for the mechanical strength and durability of concrete, and the shrinkage and cracking of concrete has always been one of the problems that cannot be effectively solved in the field of concrete engineering. High-performance concrete with high volume and low water-binder ratio, this common engineering quality problem is the main factor affecting the durability of concrete. Concrete shrinkage will have a negative impact, causing cracks in the concrete structure, significantly reducing its abili...

Examples

Embodiment 1

[0035] First, 30g of tetrahydrofuran, 30g of methyl acrylate and 12.54g of isopropanol were added to the reactor, stirred and heated to 50°C, and then a mixed solution of 2.86g of azobisisobutyronitrile and 2.86g of tetrahydrofuran was added dropwise for 12 hours. After the addition, continue to react at a constant temperature of 50°C for 6 hours to obtain a self-polymerized product polymethyl acrylate solution; adjust the temperature of the obtained self-polymerized product to 50°C, add 35.22g of n-dodecyl mercaptan and stir for 40 minutes until it is mixed Evenly, add dropwise a mixed solution of 393.80g N-isopropylacrylamide, 28.57g azobisisobutyronitrile and 28.57g tetrahydrofuran for 12 hours, continue to react at a constant temperature of 50°C for 6 hours after the dropwise addition, and then distill under reduced pressure to remove Tetrahydrofuran to obtain graft copolymerization product; mix 423.80g graft copolymerization product with 62.64g deionized water, stir and he...

Embodiment 2

[0037] First, 210g of sulfolane, 30g of butyl acrylate and 6.47g of 3-mercaptopropanol were added to the reactor, stirred and heated to 110°C, and then a mixed solution of 2.53g of tert-butyl hydroperoxide and 10.13g of sulfolane was added dropwise for 3 hours. After the dropwise addition, continue to react at a constant temperature of 110°C for 2 hours to obtain a self-polymerized product polybutylacrylate solution; adjust the temperature of the obtained self-polymerized product to 90°C, add 24.85g of 3-mercaptopropionic acid and stir for 20 minutes until it is evenly mixed. Add a mixed solution of 148.86g N-tert-butylacrylamide, 12.66g tert-butyl hydroperoxide and 50.63g sulfolane dropwise for 3 hours, continue to react at a constant temperature of 90°C for 2 hours after the dropwise addition, and then distill under reduced pressure to remove the sulfolane. Obtain graft copolymerization product; Mix 178.86g graft copolymerization product with 21.07g deionized water, stir and ...

Embodiment 3

[0039] First, 270g dimethyl sulfoxide, 30g amyl acrylate and 1.27g isopropanol were added to the reactor, stirred and heated to 70°C, then 6.56g tert-butyl peroxybenzoate and 59.02g dimethyl Mix the solution of sulfoxide for 8 hours, continue to react at a constant temperature of 70°C for 4 hours after the dropwise addition, and obtain a polyamyl acrylate solution of the self-polymerized product; adjust the temperature of the obtained self-polymerized product to 80°C, and add 32.03g of n-dodecyl Mercaptan and stirred for 25 minutes until it was mixed evenly, and then a mixed solution of 97.59g N,N'-methylene bisacrylamide, 19.67g tert-butyl peroxybenzoate and 177.04g dimethyl sulfoxide was added dropwise for 6 hours, After the dropwise addition, continue to react at a constant temperature of 80°C for 3 hours, then distill off dimethyl sulfoxide under reduced pressure to obtain a graft copolymerization product; mix 127.56 g of the graft copolymerization product with deionized wa...

technical field

[0001] The invention relates to the technical field of a temperature-responsive polycarboxylic acid for cement concrete, in particular to a comb-shaped polycarboxylic acid material synthesized by self-polymerization of an acrylic ester monomer and then grafted with a temperature-responsive monomer, followed by hydrolysis specific preparation method. Background technique

[0002] The rapid development of high-performance concrete has led to higher and higher requirements for the mechanical strength and durability of concrete, and the shrinkage and cracking of concrete has always been one of the problems that cannot be effectively solved in the field of concrete engineering. High-performance concrete with high volume and low water-binder ratio, this common engineering quality problem is the main factor affecting the durability of concrete. Concrete shrinkage will have a negative impact, causing cracks in the concrete structure, significantly reducing its abili...

Examples

Embodiment 1

[0035] First, 30g of tetrahydrofuran, 30g of methyl acrylate and 12.54g of isopropanol were added to the reactor, stirred and heated to 50°C, and then a mixed solution of 2.86g of azobisisobutyronitrile and 2.86g of tetrahydrofuran was added dropwise for 12 hours. After the addition, continue to react at a constant temperature of 50°C for 6 hours to obtain a self-polymerized product polymethyl acrylate solution; adjust the temperature of the obtained self-polymerized product to 50°C, add 35.22g of n-dodecyl mercaptan and stir for 40 minutes until it is mixed Evenly, add dropwise a mixed solution of 393.80g N-isopropylacrylamide, 28.57g azobisisobutyronitrile and 28.57g tetrahydrofuran for 12 hours, continue to react at a constant temperature of 50°C for 6 hours after the dropwise addition, and then distill under reduced pressure to remove Tetrahydrofuran to obtain graft copolymerization product; mix 423.80g graft copolymerization product with 62.64g deionized water, stir and he...

Embodiment 2

[0037] First, 210g of sulfolane, 30g of butyl acrylate and 6.47g of 3-mercaptopropanol were added to the reactor, stirred and heated to 110°C, and then a mixed solution of 2.53g of tert-butyl hydroperoxide and 10.13g of sulfolane was added dropwise for 3 hours. After the dropwise addition, continue to react at a constant temperature of 110°C for 2 hours to obtain a self-polymerized product polybutylacrylate solution; adjust the temperature of the obtained self-polymerized product to 90°C, add 24.85g of 3-mercaptopropionic acid and stir for 20 minutes until it is evenly mixed. Add a mixed solution of 148.86g N-tert-butylacrylamide, 12.66g tert-butyl hydroperoxide and 50.63g sulfolane dropwise for 3 hours, continue to react at a constant temperature of 90°C for 2 hours after the dropwise addition, and then distill under reduced pressure to remove the sulfolane. Obtain graft copolymerization product; Mix 178.86g graft copolymerization product with 21.07g deionized water, stir and ...

Embodiment 3

[0039] First, 270g dimethyl sulfoxide, 30g amyl acrylate and 1.27g isopropanol were added to the reactor, stirred and heated to 70°C, then 6.56g tert-butyl peroxybenzoate and 59.02g dimethyl Mix the solution of sulfoxide for 8 hours, continue to react at a constant temperature of 70°C for 4 hours after the dropwise addition, and obtain a polyamyl acrylate solution of the self-polymerized product; adjust the temperature of the obtained self-polymerized product to 80°C, and add 32.03g of n-dodecyl Mercaptan and stirred for 25 minutes until it was mixed evenly, and then a mixed solution of 97.59g N,N'-methylene bisacrylamide, 19.67g tert-butyl peroxybenzoate and 177.04g dimethyl sulfoxide was added dropwise for 6 hours, After the dropwise addition, continue to react at a constant temperature of 80°C for 3 hours, then distill off dimethyl sulfoxide under reduced pressure to obtain a graft copolymerization product; mix 127.56 g of the graft copolymerization product with deionized wa...

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