Effects of Molecular Structure of Polycarboxylate Water Reducers on their Performance in Cement Paste

The polycarboxylate water reducers(PCs) with different molecular structure were synthesized. The effects of molecular structure on their performance in cement paste were investigated. The results show that the PCs with a medium density of PEO side chain and/or a moderate molecular weight and its distribution have a higher dispersibility and a stronger dispersion retention stability at the same time, and that those PCs with a shorter PEO side chain exhibit a stronger dispersion retention stability. The PCs with a higher molecular weight, a lower density and/or a shorter length of PEO side chain are more easy to adsorb on the surface of cement particles. The earlier induction period is shortened while the dormant period is prolonged during the process of cement hydration in the presence of PCs. The PCs with a shorter PEO side chain show a stronger retarding effct. This effect is not very obvious with the decreasing molecular weight.

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Study on adsorption, rheology and hydration behaviours of Polycarboxylate(PCE) superplasticizer synthesized by different acid to ether ratio

Journal of Physics Conference Series ◽

10.1088/1742-6596/2133/1/012007 ◽

2021 ◽

Vol 2133 (1) ◽

pp. 012007

Author(s):

Zhijun Lin ◽

Xiaofang Zhang ◽

Zhanhua Chen ◽

Yue Xiao ◽

Yunhui Fang

Keyword(s):

Molecular Weight ◽

Adsorption Capacity ◽

Cement Paste ◽

Cement Hydration ◽

Main Chain ◽

Chain Structure ◽

Hydration Process ◽

Side Chain ◽

Structure Parameters ◽

Polycarboxylate Superplasticizer

Abstract Polycarboxylate superplasticizer is synthesised by different acid to ether ratio, which is changing the main chain structure parameters, obtained different microstructures. The effect of different microstructure PCE superplasticizer on the fluidity of cement paste, rheological thixotropy, adsorption capacity and hydration heat are studied. The results show that dispersing performance in cement with acid to ether ratio of 3.5 is the best, the molecular weight and side chain density have rather little effect on the cement hydration process.

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Less Loss of Fluidity of Polycarboxylic Acid Type Water Reducer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.3452 ◽

2011 ◽

Vol 71-78 ◽

pp. 3452-3456

Author(s):

Xun Zhong

Keyword(s):

Molecular Weight ◽

Cement Paste ◽

Side Chain ◽

Polycarboxylic Acid ◽

Acid Type ◽

Type Water ◽

Different Molecular Weight

Cement paste and concrete with different molecular weight of side-chain of polycarboxylic acid type water reducer (PC) and retarder has been researched. In this way, the method of adjusting the molecular weight of side-chain and complexing retarder to hold fluidity has been discussed. The results show that with increase molecular weight of side-chain, the dispersibility and holding dispersibility increases. With retarder and PC, the dispersibility and holding dispersibility of PC with big more molecular weight of side-chain increases and the loss of fluidity at 1h prominence reduces. But it relates to breed of cement. Especially at low ratio of water and cement, when molecular weight of side-chain is more than 2000, complexing PC and retarder can improve the fluidity and holding fluidity.

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Relationships between molecular structure and immiscibility of liquid crystalline side-chain polymers in low molecular weight nematic solvents

Macromolecules ◽

10.1021/ma00169a019 ◽

1987 ◽

Vol 20 (3) ◽

pp. 578-585 ◽

Cited By ~ 25

Author(s):

G. Sigaud ◽

M. F. Achard ◽

F. Hardouin ◽

M. Mauzac ◽

H. Richard ◽

...

Keyword(s):

Molecular Structure ◽

Molecular Weight ◽

Liquid Crystalline ◽

Side Chain ◽

Low Molecular Weight

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ANALISA KANDUNGAN BETA-GLUKAN LARUT AIR DAN LARUT ALKALI DARI TUBUH BUAH JAMUR TIRAM (Pleurotus ostreatus) DAN SHIITAKE (Lentinus edodes)

Jurnal Sains dan Teknologi Indonesia ◽

10.29122/jsti.v13i3.894 ◽

2013 ◽

Vol 13 (3) ◽

Author(s):

Netty Widyastuti ◽

Teguh Baruji ◽

Henky Isnawan ◽

Priyo Wahyudi ◽

Donowati Donowati

Keyword(s):

Molecular Structure ◽

Molecular Weight ◽

Immune System ◽

Pleurotus Ostreatus ◽

Water Soluble ◽

Low Molecular Weight ◽

Lentinus Edodes ◽

Beta Glucan ◽

Oyster Mushrooms ◽

The Difference

Beta glucan is a polysaccharide compound, generally not soluble inwater and resistant to acid. Beta glucan is used as an immunomodulator (enhancing the immune system) in mammals is usually a beta-glucan soluble in water, easily absorbed and has a low molecular weight. Several example of beta-glucan such as cellulose (β-1 ,4-glucan), lentinan (β-1 0.6-glucan) and (β-1 ,3-glucan), pleuran (β-1, 6 and β-1 ,3-glucan) are isolated from species of fungi Basidiomycota include mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes).The purpose of thisresearch activity is to obtain beta-glucan compound that can be dissolved in water and in alkali derived from fungi Basidiomycota, i.e, Oyster mushrooms (Pleurotus ostreatus) and shiitake (Lentinus edodes). The result of beta-glucan compared to characterize the resulting beta glucan that is molecular structure . The difference of beta glucan extraction is based on the differences in solubility of beta-glucan. Beta glucan could be water soluble and insoluble water.

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Metathesis Polymerization of Phenylacetylene by Tungsten Aryloxo Complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950489 ◽

1995 ◽

Vol 60 (3) ◽

pp. 489-497 ◽

Cited By ~ 4

Author(s):

Hynek Balcar ◽

Jan Sedláček ◽

Marta Pacovská ◽

Vratislav Blechta

Keyword(s):

Molecular Weight ◽

Catalytic Activity ◽

Induction Period ◽

Average Molecular Weight ◽

Molar Fraction ◽

Molar Ratio ◽

Weight Average Molecular Weight ◽

Polymer Yield ◽

Positive Effect ◽

Ligand Addition

Catalytic activity of the tungsten aryloxo complexes WCl5(OAr) and WOCl3(OAr), where Ar = 4-t-C4H9C6H4, 2,6-(t-C4H9)2C6H3, 2,6-Cl2C6H3, 2,4,6-Cl3C6H2, and 2,4,6-Br3C6H2 in polymerization of phenylacetylene (20 °C, monomer to catalyst molar ratio = 1 000) was studied. The activity of WCl5(OAr) as unicomponent catalysts increases with increasing electron withdrawing character of the -OAr ligand. Addition of two equivalents of organotin cocatalysts (Me4Sn, Bu4Sn, Ph4Sn, Bu3SnH) to WCl5(O-C6H2Cl3-2,4 ,6) has only slight positive effect (slightly higher polymer yield and/or molecular weight of poly(phenylacetylene)s was achieved). However, in the case of WOCl3(O-C6H3Cl2-2, 6) catalyst, it enhances the activity considerably by eliminating the induction period. Poly(phenylacetylene)s prepared with the catalysts studied have weight-average molecular weight ranging from 100 000 to 200 000. They are trans-prevailing and have relatively low molar fraction of monomer units comprised in cyclohexadiene sequences (about 6%).

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Dependence of viscosity and transition temperatures of a thermal rheological fluid system on the molecular weight of the side-chain crystalline block copolymer dispersant

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2019.122605 ◽

2020 ◽

Vol 243 ◽

pp. 122605 ◽

Cited By ~ 1

Author(s):

Taiga Hiromori ◽

Sho Hirai ◽

Patchiya Phanthong ◽

Ryoko Nakano ◽

Hiroshi Sekiguchi ◽

...

Keyword(s):

Molecular Weight ◽

Block Copolymer ◽

Side Chain ◽

Transition Temperatures ◽

Fluid System

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Vertical Orientation of Liquid Crystal on 4-n-Alkyloxyphenoxymethyl-Substituted Polystyrene Containing Liquid Crystal Precursor

Polymers ◽

10.3390/polym13050736 ◽

2021 ◽

Vol 13 (5) ◽

pp. 736

Author(s):

Kyutae Seo ◽

Hyo Kang

Keyword(s):

Molecular Structure ◽

Liquid Crystal ◽

Surface Energy ◽

Polymer Films ◽

Ultraviolet Irradiation ◽

Molar Fraction ◽

Side Chain ◽

Polymer Modification ◽

Vertical Orientation ◽

Surface Energies

We synthesized a series of polystyrene derivatives that were modified with precursors of liquid crystal (LC) molecules, such as 4-ethyloxyphenol (homopolymer PEOP and copolymer PEOP#; # = 20, 40, 60, and 80, where # indicates the molar fraction of 4-ethyloxyphenoxymethyl in the side chain), 4-n-butyloxyphenol (PBOP), 4-n-hexyloxyphenol (PHOP), and 4-n-octyloxyphenol (POOP), via polymer modification reaction to investigate the orientation of LC molecules on polymer films, exhibiting part of the LC molecular structure. LC molecules showed a stable and uniform vertical orientation in LC cells fabricated with polymers that have 4-ethyloxyphenoxymethyl in the range of 40–100 mol%. In addition, similar results were obtained in LC cells fabricated with homopolymers of PEOP, PBOP, PHOP, and POOP. The vertical orientation of LC molecules in LC cells fabricated with polymer films correlated to the surface energy of polymer films. For example, vertical LC orientation was observed when the total surface energies of the polymer films were lower than approximately 43.2 mJ/m2. Good alignment stabilities were observed at 150 °C and 20 J/cm2 of ultraviolet irradiation for LC cells fabricated with PEOP film.

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Crystal and molecular structure of heptacain hydrochloride

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19860264 ◽

1986 ◽

Vol 51 (2) ◽

pp. 264-270 ◽

Cited By ~ 4

Author(s):

František Pavelčík ◽

Milan Remko ◽

Jozef Čižmárik ◽

Jaroslav Majer

Keyword(s):

Molecular Structure ◽

Least Squares Method ◽

Crystal And Molecular Structure ◽

Three Dimensional ◽

Chair Conformation ◽

Piperidine Ring ◽

Side Chain ◽

Ring Plane ◽

Benzene Ring Plane ◽

Carbamate Group

The crystal and molecular structure of heptacain hydrochloride was determined from three-dimensional diffractometric data. The carbamate group was found to be rotated out of the benzene ring plane by 15.5°, whilst the piperidine ring is in a more stable chair conformation. The heptyloxy side chain is in a stable all-trans conformation. The structure was refined by the full matrix least-squares method to a final R value 0.1127 for the observed reflections.

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