Stabilizing nanocellulose-nonionic surfactant composite foams by delayed Ca-induced gelation
Number of Authors: 5
2016 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 472, 44-51 p.Article in journal (Refereed) Published
Aggregation of dispersed rod-like particles like nanocellulose can improve the strength and rigidity of percolated networks but may also have a detrimental effect on the foamability. However, it should be possible to improve the strength of nanocellulose foams by multivalent ion-induced aggregation if the aggregation occurs after the foam has been formed. Lightweight and highly porous foams based on TEMPO-mediated oxidized cellulose nanofibrils (CNF) were formulated with the addition of a nonionic surfactant, pluronic P123, and CaCO3 nanoparticles. Foam volume measurements show that addition of the non-ionic surfactant generates wet CNF/P123 foams with a high foamability. Foam bubble size studies show that delayed Ca-induced aggregation of CNF by gluconic acid-triggered dissolution of the CaCO3 nanoparticles significantly improves the long-term stability of the wet composite foams. Drying the Ca-reinforced foam at 60 degrees C results in a moderate shrinkage and electron microscopy and X-ray tomography studies show that the pores became slightly oblate after drying but the overall microstructure and pore/foam bubble size distribution is preserved after drying. The elastic modulus (0.9-1.4 MPa) of Ca-reinforced composite foams with a density of 9-15 kg/m(3) is significantly higher than commercially available polyurethane foams used for thermal insulation.
Place, publisher, year, edition, pages
2016. Vol. 472, 44-51 p.
Nanocellulose, Foams, Surfactant, Gelation, Multivalent-ion, Strength, X-ray tomography
IdentifiersURN: urn:nbn:se:su:diva-130629DOI: 10.1016/j.jcis.2016.03.031ISI: 000374620600005PubMedID: 27003498OAI: oai:DiVA.org:su-130629DiVA: diva2:933115