Tuning the nanocellulose-borate interaction to achieve highly flame retardant hybrid materials

Publication Date (Web): March 21, 2016 in Chem. Mater


We show that the pH-dependent molecular pathways for cross-linking boric acid and nanocellulose have a strong influence on the flame retardancy and ignition resistance of nanocellulose-based foams. Solid-state NMR revealed that cross-linking at alkaline conditions results in the formation of thermally stable borate ester bonds. Boric acid cross-linking also modifies the thermal degradation pathway of nanocellulose; the cellulose structure is transformed into stable aromatic char during thermal annealing and the evolution of flammable volatile levoglucosan is small. We show that composite foam panels of the nanocellulose-borate hybrids and sepiolite nanoclay prepared at alkaline conditions did not ignite on radiant heat exposure in cone calorimetry testing and maintained their structural integrity after prolonged heat exposure.

Effect of particle size on the flame retardancy of poly(butylene succinate)/Mg(OH)2 composites

Fire Mater. 2016      pdf: Click here

Poly(butylene succinate)/magnesium hydroxide (PBS/Mg(OH)2) composites were prepared by melt compounding to investigate the effect of particle size on the flame retardancy of PBS. Their flammability properties were investigated by limiting oxygen index, UL-94, and cone calorimeter tests, which suggested that the medium-sized Mg(OH)2-5 μm displayed the best flame retardancy. The residual char structure were analyzed and indicated that Mg(OH)2-5 μm could form a better protective layer than other sized particles, leading to the better flame retardancy to PBS.

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