Effect of Adding Electrolyte in Cement Paste on the Dispersing Force of Polycarboxylate-Type Superplasticizer

2009 ◽  
Vol 405-406 ◽  
pp. 160-165
Author(s):  
Jun Ying Lai ◽  
Xiao Qian Qian ◽  
Shu Lin Zhan ◽  
Min Hui Fang
Keyword(s):  
Free Radical ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Cement Paste ◽  
Electrolyte Concentration ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Hydrodynamic Diameter ◽  
Free Radical Copolymerization ◽  
Poly Ethylene

A series of water-soluble polycarboxylate-type superplasticizer (PCA) were synthesized by free-radical copolymerization of methyl acrylic acid and methoxy poly(ethylene glyco1) monoacrylate macromonomers in water solutions．Micelles were formed from the resultant PCA with predetermined hydrophobic and hydrophilic blocks in water. The hydrodynamic diameter and size distribution of micelles were determined by dynamic light scattering. The change of the concentration of the electrolyte results directly in the variation of the dispersing force of PCA in cement paste. The dispersing force degrades with increasing electrolyte concentration.

scholarly journals EXTRACTION AND REEXTRACTION OF HISTIDINE AND RIBOFLAVIN BY N-VINYLCAPROLACTAME COPOLYMERS WITH 1-VINYL- AND 1-METHACRYLOYL-3,5-DIMETHYLPYROZOLE

2018 ◽  
Vol 59 (7) ◽  
pp. 55
Author(s):  
Maria S. Lavlinskaya ◽  
Gennadiy V. Shatalov ◽  
Nadezhda Ya. Mokshina ◽  
Oksana A. Pakhomova ◽  
Vyacheslav A. Kuznetsov
Keyword(s):  
Free Radical ◽  
Uv Spectroscopy ◽  
Aqueous Media ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Solution Temperature ◽  
Free Radical Copolymerization ◽  
Critical Solution Temperature ◽  
Two Phases ◽  
Degree Of Extraction

Copolymers of N-vinylcaprolactam (VC) with 1-vinyl-3,5-dimethylpyrazole (VDMP) and 1-methacryloyl-3,5-dimethylpyrazole (MDMP) were synthesized by free radical copolymerization  in dioxane with azodiisobutironitrole as initiator. Both water-soluble and water-insoluble copolymers were obtained. The copolymers compositions were determined by FTIR and UV-spectroscopy. The copolymerization constants were calculated and they were: for VC (М1)–VDMP, r1 = 0.65 ± 0.03, r2 = 0.43 ± 0.03; for VC (М1)–MDMP, r1 = 0.79 ± 0.04, r2 = 0.21 ± 0.02. These values show that VC (М1) exhibits somewhat higher activity compared to М2 and that the tendency toward alternation of comonomer units is more pronounced in VC–MDMP copolymers (r1r2 = 0.17) compared to VC–VDMP copolymers (r1r2 = 0.27). It was found that VC–VDMP copolymers are water-soluble at VC content higher than 75 mol %, and VC–MDMP copolymers at VC content higher than 88 mol %. The water-soluble copolymers based on VC have lower critical solution temperature. Their values are in range of 54-69 °C. Two-phases water-salts systems based on synthesized water-soludle thermoresponsive copolymers are proposed for histidine and riboflavin (re)extraction in aqueous media. It was found that extraction systems based on VC-VDMP copolymers are more efficient then VC-MDMP systems. Degree of extraction for both substances in a case of VC-VDMP copolymers achieved 96%. Reextraction carried out by thermoprecipitation of VC (co)polymers. It was shown that reextraction is more efficient at pH 7.6 and its degree achieved 61.7 % for histidine.

scholarly journals Strong Antimicrobial Activity of Highly Stable Nanocomposite Containing AgNPs Based on Water-Soluble Triazole-Sulfonate Copolymer

Pharmaceutics ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 206
Author(s):  
Alexander Pozdnyakov ◽  
Artem Emel’yanov ◽  
Anastasiya Ivanova ◽  
Nadezhda Kuznetsova ◽  
Tat’yana Semenova ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Reduction ◽  
Gel Permeation Chromatography ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Morphological Properties ◽  
Hydrodynamic Diameter ◽  
Scanning Calorimetry ◽  
Free Radical Copolymerization ◽  
Strong Antimicrobial Activity

A new hydrophilic polymeric nanocomposite containing AgNPs was synthesized by chemical reduction of metal ions in an aqueous medium in the presence of the copolymer. A new water-soluble copolymer of 1-vinyl-1,2,4-triazole and vinylsulfonic acid sodium salt (poly(VT-co-Na-VSA)) was obtained by free-radical copolymerization and was used as a stabilizing precursor agent. The structural, dimensional, and morphological properties of the nanocomposite were studied by UV–Vis, FTIR, X-ray diffraction, atomic absorption, transmission and scanning electron microscopy, dynamic and electrophoretic light scattering, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. Hydrodynamic diameter of macroclubs for the copolymer was 171 nm, and for the nanocomposite it was 694 nm. Zeta potential for the copolymer was −63.8 mV, and for the nanocomposite it was −70.4 mV. The nanocomposite had strong antimicrobial activity towards Gram-negative and Gram-positive microorganisms: MIC and MBC values were in the range of 0.25–4.0 and 0.5–8.0 μg/mL, respectively.

High-pressure free-radical copolymerization of ethene and 2-ethylhexyl acrylate

1996 ◽  
Vol 197 (12) ◽  
pp. 4119-4134 ◽  
Author(s):  
Michael Buback ◽  
Thomas Dröge ◽  
Alex Van Herk ◽  
Frank-Olaf Mähling
Keyword(s):  
High Pressure ◽  
Free Radical ◽  
Radical Copolymerization ◽  
Free Radical Copolymerization

Free Radical Copolymerization of Ethylene with Vinyl Acetate under Mild Conditions

2017 ◽  
Vol 50 (9) ◽  
pp. 3516-3523 ◽  
Author(s):  
A. Zarrouki ◽  
E. Espinosa ◽  
C. Boisson ◽  
V. Monteil
Keyword(s):  
Free Radical ◽  
Vinyl Acetate ◽  
Radical Copolymerization ◽  
Free Radical Copolymerization ◽  
Mild Conditions

Synthesis and characterization of hyperbranched associative polyacrylamide

RSC Advances ◽  
2016 ◽  
Vol 6 (45) ◽  
pp. 39522-39529 ◽  
Author(s):  
Wanfen Pu ◽  
Daijun Du ◽  
Rui Liu ◽  
Jiongyi Gu ◽  
Kewei Li ◽  
...  
Keyword(s):  
Free Radical ◽  
Radical Copolymerization ◽  
Synthesis And Characterization ◽  
Functional Monomer ◽  
Free Radical Copolymerization ◽  
Ultrafine Silica ◽  
Hyperbranched Polyamide

HDPAM was synthesized by water free-radical copolymerization based on functional hyperbranched polyamide-modified ultrafine silica as functional monomer.

Strain hardening and highly resilient hydrogels crosslinked by chain-extended reactive pseudo-polyrotaxane

RSC Advances ◽  
2014 ◽  
Vol 4 (100) ◽  
pp. 56791-56797 ◽  
Author(s):  
Yulin Cui ◽  
Mei Tan ◽  
Aidi Zhu ◽  
Mingyu Guo
Keyword(s):  
Free Radical ◽  
Strain Hardening ◽  
Radical Copolymerization ◽  
Free Radical Copolymerization

Hydrogels with obvious strain hardening and high resilience properties in both stretching and compressing processes are constructed by simple free-radical copolymerization of acrylamide and reactive pseudo-polyrotaxane.

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