Research on synthesis and action mechanism of polycarboxylate superplasticizer

Abstract

The relationship between the structure and performance of polycarboxylate superplasticizer was analyzed. The respective functions of the structure units of the main and branched chains were discussed. The progress of synthesis and molecular structure design and synthesis of polycarboxylate superplasticizer were reviewed according to the difference in the structure unit of the main chain. Results indicated that their performance is related to the structure unit of the main and branched chains, as well as the position and species of functional groups. The polycarboxylate superplasticizer, which had suitable graft and block polymers of polyethylene glycol or polyoxyethylene, and a suitable sulfonic group, had small slump loss besides high water-reducing performance. On the other hand, the hydroxyl group at the end of the chain causes gelation easily. On the basis of the items mentioned above, as well as the source and cost of raw materials, esterification of polyethylene glycol and acrylic acid were first adopted using para-toluene sulfonic acid as catalyst, then polymerized with sodium sulfonate methacrylate. A certain amount of acrylic was added in order to regulate both the polymerization degree of the main chain and the ratio of carboxyl and sulfonic groups in the branched chain. As a result, the high performance superplasticizer has been synthesized (was obtained). The divergence of the cement plasma is about 200 mm when the addition amount of superplasticizer is 0.16%−0.20% of cement weight, and the ratio of the water and cement is 0.29.

Polycarboxylate Based Superplasticizers as Dispersant Agents for Exfoliated Graphene Nanoplatelets Reinforcing Cement Based Materials

“…The experimental results in the present study show that a polycarboxylate polymer based superplasticizer is necessary for the effective dispersion of the xGnPs for cement-based materials. The polycarboxylate based superplasticizers are macromolecular surfactants and their molecules look like a comb [18]. Their structure typically consists of an adsorbing anionic backbone and non-ionic side chains that aren't adsorbed [19], Fig.…”

“…Typical variations in their structure is the length of the backbone and side chains, the number of side chains and the nature of the monomers making up either the backbone or the side chains [22]. They are known to absorb on the cement grains and induce steric hindrance between surfaces which reduces or suppresses the otherwise attractive interparticle van der Waals forces [18]. Similar attractive van der Waals forces are developed between the graphene nanoplatelets that lead to their agglomeration.…”

RP-LC Determination of Residual Monomers in Polycarboxylate Superplasticizers

“…The first two types were usually called micromolecular monomers and the last was called macromolecular monomer. Since polycarboxylate superplasticizers were synthesized by copolymerization of different monomers [16,17], chromatographic separation results of seven monomers in mixed standard solution were investigated at the same time in order to suit the determination method to more extensive application. Impurities in monomers such as hydroquinone and toluene-p-sulfonic acid should be separated by chromatography.…”

“…Typical PCs mainly include polyacrylic acid system, polymethylacrylic acid system and polymaleic acid system [16,17], and monomers for PCs synthesis include acrylic acid (AA), methylacrylic acid (MAA), maleic anhydride (MA), sodium methylallyl sulfonate (MAS), 2-acrylamido-2-methylpropane sulfonic acid (AMPS), methoxypolyethylene glycol acylate (MPEGA) and methoxypolyethylene glycol methyl acrylate (MPEGMA), etc. [2-6, 16, 17].…”

Synthesis of new polyether polycarboxylate superplasticizer

“…Previous research revealed that the polycarboxylate superplasticizer popularized was based on free radical polymerization reaction under a certain temperature from some olefin unsaturated monomers and the polyethylene glycol unsaturated carboxylic acid esters, which were prepared by the esterification reaction of polyethylene glycol with the over-dosaged unsaturated carboxylic acid [1][2][3][4][5][6][7][8][9][10][11][12] . However, the present domestic product craft for unsaturated carboxylic acid esters is not mature, which engender certain influence on the industrialization manufacture.…”