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High-performance carboxylate superplasticizers for concretes: Interplay between the polymerization temperature and properties

Tajbakhshian, A ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1002/app.44908
  3. Abstract:
  4. Polycarboxylate superplasticizers based on acrylic acid (AA) and maleic anhydride (MAn) were synthesized via free-radical copolymerization with an ethylene glycol monomer and characterized. The copolymerization temperature (ranging from 50 to 90 °C) appeared to be the key operating factor governing the chemical structure of the superplasticizers. The chemical structures of the products were analyzed by gel permeation chromatography, whereas an optimized sample was further analyzed by Fourier transform infrared spectroscopy and 1H-NMR. Superplasticizers of the AA and MAn classes were then incorporated into concrete, and their performances were measured by slump and slump loss tests, where a large dependency of the microstructure on the synthesis temperature was recognized. The optimum temperatures were found to be 50 and 80 °C for the AA and MAn modifiers, respectively. At their own optimum temperatures, the AA and MAn superplasticizer revealed slump losses from 23 to 4 cm and 15 to 5 cm, respectively, after 45 min. The chemical structures of the plasticizers were patterned illustratively to speculate the performance of each superplasticizer according to changes that took place in the backbone length and side-chain density. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44908. © 2017 Wiley Periodicals, Inc
  5. Keywords:
  6. Plasticizer ; Radical polymerization ; Acrylic monomers ; Carboxylation ; Chemical analysis ; Chromatography ; Concretes ; Copolymerization ; Ethylene ; Ethylene glycol ; Fourier transform infrared spectroscopy ; Free radical polymerization ; Free radicals ; Gel permeation chromatography ; Molecular recognition ; Plasticizers ; Polymerization ; Reinforced plastics ; Solvents ; Structure (composition) ; Acrylic acids ; Free radical copolymerization ; Operating factors ; Optimum temperature ; Polycarboxylates ; Polymerization temperature ; Superplasticizers ; Synthesis temperatures ; Ascorbic acid
  7. Source: Journal of Applied Polymer Science ; Volume 134, Issue 23 , 2017 ; 00218995 (ISSN)
  8. URL: https://onlinelibrary.wiley.com/doi/abs/10.1002/app.44908