TY - JOUR
T1 - Processing and functional assessment of anisotropic cellulose nanofibril/Alolt/sodium silicate
T2 - based aerogels as flame retardant thermal insulators
AU - Gorgieva, Selestina
AU - Jančič, Urška
AU - Hribernik, Silvo
AU - Fakin, Darinka
AU - Stana Kleinschek, Karin
AU - Medved, Sergej
AU - Fakin, Tomaž
AU - Božič, Mojca
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Abstract: This work concerns freeze-dry processing of CNF aerogels, including aluminum hydroxide trihidrate (Alolt) particles and Sodium silicate, as active and passive flame retardants, respectively. Alkalinity of Sodium silicate promotes stability, dissociation and co-precipitation of Al(OH)3 component onto CNFs. The (auto)fluorescence-enabled confocal microscopy enabled visualization of anisotropic microstructure with open and closed-cell segments, depicting the Alolt as single and aggregated particles. Low thermal conduction (~ 0.045 W/mK) was estimated, irrespective of composition, while Alolt was found to reduce (by 30%) the aerogel moisture content. Sodium silicate promotes char formation as passive action, reducing the evolution of gaseous species, while burning test shows complete flame retardation through active endothermic reaction assigned to Alolt. Additive combinations did not amplify, nor diminish, the flame retardant effect of particular component, yet affected positively the elastic modulus. Considering simple “green” processing, low additive load, and high insulation and flame retardant efficiency, these aerogels hold promise as thermal insulation materials. Graphic abstract: [Figure not available: see fulltext.].
AB - Abstract: This work concerns freeze-dry processing of CNF aerogels, including aluminum hydroxide trihidrate (Alolt) particles and Sodium silicate, as active and passive flame retardants, respectively. Alkalinity of Sodium silicate promotes stability, dissociation and co-precipitation of Al(OH)3 component onto CNFs. The (auto)fluorescence-enabled confocal microscopy enabled visualization of anisotropic microstructure with open and closed-cell segments, depicting the Alolt as single and aggregated particles. Low thermal conduction (~ 0.045 W/mK) was estimated, irrespective of composition, while Alolt was found to reduce (by 30%) the aerogel moisture content. Sodium silicate promotes char formation as passive action, reducing the evolution of gaseous species, while burning test shows complete flame retardation through active endothermic reaction assigned to Alolt. Additive combinations did not amplify, nor diminish, the flame retardant effect of particular component, yet affected positively the elastic modulus. Considering simple “green” processing, low additive load, and high insulation and flame retardant efficiency, these aerogels hold promise as thermal insulation materials. Graphic abstract: [Figure not available: see fulltext.].
KW - Cellulose nanofibrils
KW - Composite
KW - Flame retardance
KW - Freeze-drying
KW - Thermal insulation
UR - http://www.scopus.com/inward/record.url?scp=85076206017&partnerID=8YFLogxK
U2 - 10.1007/s10570-019-02901-3
DO - 10.1007/s10570-019-02901-3
M3 - Article
AN - SCOPUS:85076206017
SN - 0969-0239
JO - Cellulose
JF - Cellulose
ER -