Direct foaming and seeding of highly porous, lightweight gypsum

Elisabet Roch Isern, Gary Lynn Messing

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

This paper describes the direct-foaming of plaster of Paris (CaSO4·1/2H2O) with up to 1.7 wt% of a nonionic surface-active agent to obtain highly porous, lightweight gypsum (CaSO4·2H2O) with 65-70% total porosity and a homogeneous, bimodal pore size distribution. Based on viscosity and temperature changes in the setting plaster of Paris slurry, the nonionic surfactant is seen to retard gypsum crystallization and thus extend the working time at higher water to solid ratios. The increase in viscosity during gypsum crystallization stabilizes the macropores formed during foaming. Gypsum foams of 32% density with a submicron matrix pore size, and relatively uniform macropore size of ∼100 m were obtained. Seeding the process with 0.5 wt% 100 m diameter gypsum particles accelerates gypsum crystallization in the presence of the nonionic surfactant and results in a more uniform, finer (92 m) macropore structure due to less time for bubble coalescence.

Original languageEnglish (US)
Pages (from-to)2244-2251
Number of pages8
JournalJournal of Materials Research
Volume31
Issue number15
DOIs
StatePublished - Aug 15 2016

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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