Amino-silica microcapsules as effective curing agents for polyurethane foams
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The present paper regards the development of functional microcapsules (MCs), containing encapsulated glycerol, to act as sustainable solid curing agents for one-component polyurethane (PU) foams. They consist of silica-based MCs with an aminosilane surface treatment, obtained through sol–gel processing technique. These MCs are intended to burst and release their content only at the spraying process, in order to promote an accelerated curing of the PU foam. The superficial amino groups react with the isocyanate groups present in the PU pre-polymer, producing polyurea moieties on the MCs’ surface, which prevents the leaching of encapsulated glycerol inside the PU aerosol can. This enables the long shelf life of the product, required for commercial application. The amino-silica MCs exhibit a perfect spherical shape, without significant leaching, in opposition to silica-based MCs and led to a significant increase in the curing rate of the PU foam. The study involved various characterization techniques, such as scanning electron microscopy, Fourier transformed infrared spectroscopy, thermogravimetric analyses, leaching and curing speed evaluation.
KeywordsFoam Polyurea Isocyanate Group Aminosilane Porous Microsphere
ACM acknowledges the financial support from Science and Technology Foundation (FCT) through Post-Doc fellowship (SFRH/BPD/96697/2013). We are grateful to Profs. Mario Pagliaro and Rosaria Cirimmina for purposeful cooperation and to Prof. Ricardo Simões for the development and supply of the nozzle.
- 1.IAL Consultants (2014) Global overview of the spray polyurethane foam (SPF) & one component foam (OCF) markets. http://www.ialconsultants.com/uploads/CUBE_press_release/2014-08-29/SPFOCF_press_release.pdf. Accessed 11 April 2016
- 2.Thomson T (2005) Polyurethanes as specialty chemicals: principles and applications. CRC Press, Boca RatonGoogle Scholar
- 3.I. John Wiley & Sons (2003) Ed., MDI and TDI: safety, health and the environment: a source book and practical guide. Wiley, West SussexGoogle Scholar
- 7.De Schrijver A (2012) The foam manual, polyurethane foams systems for professionals and DIY. Aster De Schrijver, HergiswilGoogle Scholar
- 8.U.S. Environmental Protection Agency (2011) Methylene diphenyl diisocyanate (MDI) and related compounds action plan summary. http://www.wftaylor.com/wp-content/uploads/2012/03/EPA_MDI_Action_Plan.pdf. Accessed 11 April 2016
- 17.Almeida RM, Marques AC (2005) Characterization and properties of sol–gel materials and products. In: Sakka S (ed) Handbook of sol–gel science and technology: processing, characterization and applications, vol II. Kluwer, Osaka, pp 65–89Google Scholar
- 18.Anderson DR (1974) Chapter 10: infrared, Raman and ultraviolet spectroscopy. In: Lee Smith A (ed) Analysis of silicones. Wiley, New YorkGoogle Scholar