Citation

Köklükaya O, Carosio F, Grunlan JC, Wagberg L. ACS Appl. Mater. Interfaces 2015; 7(42): 23750-23759.

Copyright

(Copyright © 2015, American Chemical Society)

DOI

10.1021/acsami.5b08105

PMID

26457504

Abstract

The highly flammable character of cellulose-rich fibers from wood limits their use in some advanced materials. In order to suppress the flammability and introduce flame-retardant properties to individual pulp fibers, nanometer thin films consisting of cationic chitosan (CH) and anionic poly(vinylphosphonic acid) (PVPA) were deposited on fibers using the layer-by-layer (LbL) technique. The build-up of the multilayer film was investigated in the presence and absence of salt (NaCl) using model cellulose surfaces and a quartz crystal microbalance technique. Fibers were then treated with the same strategy and the treated fibers were used to prepare paper sheets. A horizontal flame test (HFT) and cone calorimetry were conducted to evaluate the combustion behavior of paper sheets as a function of the number of bilayers deposited on fibers. In HFT, paper made of fibers coated with 20 CH/PVPA bilayers (BL), self-extinguished the flame, while uncoated fibers were completely consumed. Scanning electron microscopy of charred paper after HFT revealed that a thin shell of the charred polymeric multilayer remained after the cellulose fibers had been completely oxidized. Cone calorimetry demonstrated that the phosphorus-containing thin films (20 BL is ̴ 25 nm) reduced the peak heat release rate by 49%. This study identifies a unique and highly effective way to impart flame-retardant characteristic to pulp fibers and the papers made from these fibers.

Language: en