For a slump retainer, isoprenyl ether (TPEG, also written IPEG) held slump longest and an HPEG retainer lost the most in the one same-recipe comparison we found. The family only shows when everything else is held fixed, though: the ester comonomer and the polymerisation recipe move retention at least as far. The slow release itself comes from a hydrolysable ester comonomer such as hydroxypropyl acrylate (HPA).
Papers do not use the monomer abbreviations consistently, so below HPEG means the methallyl ether, TPEG the isoprenyl ether, and EPEG and VPEG the vinyl ethers.
What Makes a PCE Slump-Retaining
A PCE holds slump when part of its anchoring groups arrive late. Ester groups on the polymer hydrolyse in the alkaline pore solution and turn into carboxylate anchors over time, so the polymer keeps adsorbing and dispersing cement after an ordinary PCE has been used up.
The second half of the design is a low anchor density at the start, so that less of the polymer adsorbs in the first minutes and more stays in solution as a reserve.
A retarder keeps slump by delaying hydration and pushes setting time back with it; a slump-retaining PCE keeps releasing dispersant, and a W. R. Grace patent claims that route as extending slump without significantly affecting setting time.
Which Monomer Family Gives the Best Slump Retention
With the rest of the recipe held fixed, the isoprenyl ether (TPEG, called IPEG in the study) gave the best slump retention, but inside one family the recipe moves retention just as far. A 2023 study in the Journal of Dispersion Science and Technology made three retainers to the same recipe code, changing only the macromonomer. Concrete with the IPEG retainer held 440 mm of slump flow after 150 min, while concrete with the HPEG retainer had almost no fluidity left after 120 min.
Inside one family, a 2024 nine-sample test by Chongqing JianYan KZJ New Materials and Chongqing University, all on EPEG-2400 with acrylic acid and HPA, spread the 150-min slump-flow loss from 5.98 % to 38.74 %.
We found no study that compares one retainer across several cements, so treat any family ranking as a starting point and run the candidate retainer in your own cement and mix. Switching families also means re-optimising the ester ratio and polymerisation conditions; in the references we checked, a dosage change was not shown to correct the difference.
HPEG
HPEG retained least of the three in the same-recipe study: its retainer gave the smallest initial slump flow and the largest loss over time.
HPEG shares its cost advantage with TPEG: a 2022 ACI review of superplasticizers names HPEG and IPEG PCEs the most cost-effective PCEs known at the time. The HPEG 2400 we supply is a methallyl alcohol polyoxyethylene ether of MW 2400 ± 100 g/mol.
TPEG
TPEG, the isoprenyl ether that papers also call IPEG, retained best in the same-recipe study. The IPEG retainer kept cement-paste slump flow unchanged for 240 min.
The TPEG 2400 we supply is an isoprenyl alcohol polyoxyethylene ether of 2,400 ± 100 Da.
Vinyl-Ether Monomers (EPEG and VPEG)
In the same-recipe study, the EPEG retainer released early: paste flow rose quickly within 120 min, and its concrete retention came out below the IPEG retainer’s. The best sample of the 2024 EPEG-2400 test shows a vinyl-ether retainer can hold slump well once the recipe is tuned.
Vinyl ethers are polymerised cold: a 2025 Buildings study reached over 95 % EPEG conversion at 20 °C, where conventional macromonomers need 60–90 °C.
EPEG is also the least proven: it is one of the recent vinyl-ether PCEs whose overall performance is still being evaluated. For VPEG (4-hydroxybutyl vinyl ether), a Levima patent claims it as a slump-retainer macromonomer at MW 1000–6000, but we found no published retention data for it.
The EPEG 3000 we supply is a vinyl-ether macromonomer of 3000 ± 100 g/mol, printed as diethylene glycol monovinyl ether polyoxyethylene ether. The EPEG in the published tests is the ethylene glycol monovinyl type, so those results were not measured on it.
Which Ester Comonomer Goes With the Macromonomer
A hydroxyalkyl acrylate usually supplies the slow release, and of the common ones hydroxypropyl acrylate (HPA) came out best. An ACI symposium paper that built the same PCE with methyl acrylate, hydroxyethyl acrylate (HEA) and HPA found the HPA version gave the best paste flow and concrete slump retention. A Sobute New Materials patent claims HEA, HPA, hydroxyethyl methacrylate and hydroxypropyl methacrylate as its ester monomer.
A diester can release more slowly still. A 2022 study of slow-release PCEs on HPEG found dimethyl itaconate gave a stronger slow release than HEA or HPA, with cement-paste flow rising from 190 mm to 255 mm within 2 h.
Blending esters that hydrolyse at different rates spreads the release over time. A 2021 Materials Reports study combined HEA and HPA, with HPA at 60 % of the ester monomers, and reported 4 h of slump retention at 30 °C.
More ester is not better. In a 2023 KZJ New Material Group series on EPEG with HEA, concrete spread after 60 min rose as the HEA-to-EPEG molar ratio went from 1.32 to 4.40 and fell again at 5.50; the side-chain molecular weight changed along with the ratio in that series. The 2024 EPEG-2400 test with HPA likewise found its best retention at the lowest ester-to-ether ratio it tried, 2.0.
Which Molecular-Weight Grade for a Slump Retainer
A grade around 2400 is where published slump-retainer recipes sit, and the graded series we found gave its best retention between 2400 and 4000.
In the 2023 KZJ series on EPEG of 1200, 2400, 3000, 4000 and 6000, retention rose and then fell with side-chain length. Retention in that series peaked at an EPEG of 2400 when the ester ratio rose with the molecular weight, and at 4000 when the ratio was held fixed; the paper does not report the 3000 grade on its own.
The Sobute patent claims the opposite direction: side chains of 110 to 350 ethylene-oxide units, with worked examples on macromonomers of 6000 to 12000. In the Sobute patent’s comparison at 0.1 % dosage, swapping in an allyl macromonomer of 2400 left cement-paste flow at 223 mm after 180 min, against 310 mm for its allyl 8000 example. The graded series and the patent used different starters, esters and tests, so neither settles whether going above 4000 pays.
Using the Same Macromonomer as the Water Reducer
The retainer does not have to use the reducer’s macromonomer, and we found no study or patent example that tests a matched pair against an unmatched one. In the W. R. Grace patent, the worked example that pairs the two uses two Nippon Shokubai polymers of the same type; the retainer differs only in having fewer carboxylate anchors per side chain. The Grace example blends reducer, retainer and sodium gluconate at 1 : 2 : 0.6 by weight.
Using one macromonomer for both components means one raw material to qualify and stock; a different family for the retainer is worth the second raw material only when it retains better in your cement. Test the blend rather than each component.
On dosage, the Sobute patent’s application example added its retainer at 0.02 % to 0.1 % on top of 0.1 % of a commercial PCE, a retainer-to-reducer ratio of 0.2 : 1 to 1 : 1. The patent’s description warns that too much retainer can make the concrete gain flow later, or segregate and bleed.