Polycarboxylate Ether

In order to achieve the desired fluidity and better dispersion of nanoparticles, the polycarboxylate ether based superplastisiser was incorporated into all mixes. The content of superplastisiser was adjusted for each mixture to keep the fluidity of the mortars constant. Natural river sand was used with the fraction of sand, which passed through a 1.18 mm sieve and... 

Keywords biopolymers, cementitious materials, polycarboxylate ether, stabilising agent, starch ether, self-compacting concrete, superplasticizer... 

Furthermore two types of polycarboxylate ether superplasticizer (PCE) with varying charge density of the backbone were chosen for the investigations. The backbone charge determines the adsorption velocity of superplasticizers on clinker phases and early hydration products and thus influences the time dependent rheological performance as well as the setting. Table 1 provides a detailed overview of the used admixtures. 

Figure 2.21 shows the heat flow development of cement pastes without and with 0.3% of superplasticiser in simultaneous and in delayed addition mode (Winnefeld 2008). Products based on polycarboxylate ether (PCE) and sulfonated naphthalene-formaldehyde polycondensate (SNF) were applied. Compared to the plain paste, the pastes with admixtures show a retardation of the setting and a delay of the main hydration peak. In... 

Note IRA isopropanol PAA polyacrylic acid PCE polycarboxylate ether. 

Figure 6. Chemical structures of polycarboxylic acid esters and ethers.

At the same time, the industry embarked on an intensive search for phosphate substitutes. Of a very large number of experimental organic builders, a few substances reached commercialization or near-commercialization, including trisodium nitrilotriaceate (NTA), trisodium carboxymethoxysuccinate (CMOS) (181) and trisodium carboxymethyltartronate (182). As discussed above, sodium citrate ether carboxylates have achieved widespread use as phosphate substitutes. Polymeric builders (polyelectrolytes) proved to be effective calcium sequestrants, but failed to satisfy the criterion of acceptable biodegradability. Interestingly, some monomeric polycarboxylates proved to be even more powerful calcium sequestrants than sodium tripolyphosphate but were not sufficiently biodegradable (183). 

Diamino-polycarboxylates are analogues of EDTA and can have a polymethylene chain of variable length as a spacer between the amine nitrogen atoms, in which branching, ethereal functionalities, or a fifth -COO group can also be present (Figure 14). 

The third class of ligands we mention here is that of polyaza-macrocycles, crown ethers, and calixarenes bearing polycarboxylate arms.293 294 299-301... 

Polycarboxylate crown ethers such as (205) are suitable ligands for potentiometric studies of mixed-metal complexes of Al3+ and alkali or alkaline-earth cations.303 A similar (+)-18-crown-6-tetracarboxylic acid, chemically immobilized on a chiral stationary phase (CSP), can selectively recognize both enantiomers of some analytes.304 Calixarene polycarboxylates such as (206) and (207) are useful ligands toward alkali-305,306 and also transition-metal ions,307 308 with applications in... 

Soon after the introduction of convergent dendrimer synthesis, " hemispherical, aryl-ester-coated, benzyl ether-based dendrons were reported. Attachment to a divalent core and conversion to the polycarboxylate 25 (Fig. 5) yielded dendriiners that facilitated a 200-fold increase in pyrene (26) solubility in water eompared with that of pure water without the dendrimer. Notably, use of sodium dodecyl sulfate (SDS above cmc 9 X 10 M) for pyrene encapsulation resulted in only an 100-fold enhancement. 

It means that the chemical stmcture of SP molecules on their properties from different producers can vary, in spite of the same basic stmcture and mechanism of interaction with concrete mixture. The fluidity of paste increases with time in some cases, as the polycarboxylate superplasticizers, composed of mullein anhydride, poly-oxyethylene and aryl ether, are used. 

The self compacting concrete mixture should have high plastic viscosity and low yield stress value. It is ensured by the high content of fine powder fraction (Fig. 10.4) and low w/c ratio [33], but the use of superplasticizers is essential too. It must be the polycarboxylates or poly carboxylic ethers admixtures. SCC technology... 

DeTinltlon Polymer consisting of partial butyl ester of the polycarboxylic acid formed from vinyl methyl ether and maleic anhydride Empirical (C H,805) ... 

CAS 31307-95-6 54578-88-0 54077-45-1 56091-51-1 Synonyms 2-Butenedioic acid, polymer with methoxyethene, 1-methylethyl ester Isopropyl ester of PVM/MA copolymer (INCI) Definition Polymer consisting of the partial Isopropyl ester of the polycarboxylic resin formed from vinyl methyl ether and maleic anhydride... 

Sodium C4-12 olefin/maleic acid copolymer Sodium decyl sulfate Sodium polycarboxylate Sodium polymethacrylate Sodium polynaphthalene sulfonate Sodium tallate Soyamide DEA Stearamide Stearamine Styrene/MA copolymer Tall oil acid Tall oil hydroxyethyl imidazoline Tallow dipropylene triamine TEA-dodecylbenzenesulfonate Tricontanyl PVP Tridecyl neopentanoate Tridecyl trimellitate Triisocetyl citrate Trioctyidodecyl citrate dispersant, pigment dispersions Disodium decyl diphenyl ether disulfonate lsotrideceth-9 Octoxynol-11... 

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