Issue 8, 2018

All-natural and highly flame-resistant freeze-cast foams based on phosphorylated cellulose nanofibrils

Abstract

Pure cellulosic foams suffer from low thermal stability and high flammability, limiting their fields of application. Here, light-weight and flame-resistant nanostructured foams are produced by combining cellulose nanofibrils prepared from phosphorylated pulp fibers (P-CNF) with microfibrous sepiolite clay using the freeze-casting technique. The resultant nanocomposite foams show excellent flame-retardant properties such as self-extinguishing behavior and extremely low heat release rates in addition to high flame penetration resistance attributed mainly to the intrinsic charring ability of the phosphorylated fibrils and the capability of sepiolite to form heat-protective intumescent-like barrier on the surface of the material. Investigation of the chemical structure of the charred residue by FTIR and solid state NMR spectroscopy reveals the extensive graphitization of the carbohydrate as a result of dephosphorylation of the modified cellulose and further dehydration due to acidic catalytic effects. Originating from the nanoscale dimensions of sepiolite particles, their high specific surface area and stiffness as well as its close interaction with the phosphorylated fibrils, the incorporation of clay nanorods also significantly improves the mechanical strength and stiffness of the nanocomposite foams. The novel foams prepared in this study are expected to have great potential for application in sustainable building construction.

Graphical abstract: All-natural and highly flame-resistant freeze-cast foams based on phosphorylated cellulose nanofibrils

Supplementary files

Article information

Article type
Paper
Submitted
12 Dec 2017
Accepted
05 Feb 2018
First published
06 Feb 2018
This article is Open Access
Creative Commons BY license

Nanoscale, 2018,10, 4085-4095

All-natural and highly flame-resistant freeze-cast foams based on phosphorylated cellulose nanofibrils

M. Ghanadpour, B. Wicklein, F. Carosio and L. Wågberg, Nanoscale, 2018, 10, 4085 DOI: 10.1039/C7NR09243A

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