Elastic Aerogels of Cellulose Nanofibers@Metal–Organic Frameworks for Thermal Insulation and Fire Retardancy  

作　　者：Shengyang Zhou Varvara Apostolopoulou‑Kalkavoura Marcus Vinicius Tavares da Costa Lennart Bergstrom Maria Stromme Chao Xu 

机构地区：[1]Nanotechnology and Functional Materials,Department of Engineering Sciences,Angstrom Laboratory,Uppsala University,75121 Uppsala,Sweden [2]Department of Materials and Environmental Chemistry,Stockholm University,10691 Stockholm,Sweden [3]Applied Mechanics,Department of Engineering Sciences,Angstrom Laboratory,Uppsala University,75121 Uppsala,Sweden

出　　处：《Nano-Micro Letters》2020年第1期102-114,共13页纳微快报（英文版）

基　　金：the Aforsk research grant (19-493)

摘　　要：Metal–organic frameworks(MOFs)with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials.However,the difficulties in processing and shaping MOFs have largely hampered their applications in these areas.This study outlines the fabrication of hybrid CNF@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers(CNFs)with continuous nanolayers of MOFs.The cross-linking gives the aerogels high mechanical strength but superelasticity(80%maximum recoverable strain,high specific compression modulus of^200 MPa cm3 g−1,and specific stress of^100 MPa cm3 g−1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity,which render the aerogels with relatively low thermal conductivity of^40 mW m−1 K−1.The hydrophobic,thermally stable MOF nanolayers wrapped around the CNFs result in good moisture resistance and fire retardancy.This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials.It presents a pathway for the design of thermally insulating,superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.Metal-organic frameworks（MOFs） with high microporosity and relatively high thermal stability are potential thermal insulation and flame-retardant materials.However,the difficulties in processing and shaping MOFs have largely hampered their applications in these areas.This study outlines the fabrication of hybrid CNP@MOF aerogels by a stepwise assembly approach involving the coating and cross-linking of cellulose nanofibers（CNPs） with continuous nanolayers of MOFs.The cross-linking gives the aerogels high mechanical strength but superelasticity(80% maximum recoverable strain,high specific compression modutus of～200 MPa cm3 g-1,and specific stress of～100 MPa cm3 g-1).The resultant lightweight aerogels have a cellular network structure and hierarchical porosity,which render the aerogels with relatively low thermal conductivity of～40 mW m-1 K-1.The hydrophobic,thermally stable MOF nanolayers wrapped around the CNPs result in good moisture resistance and fire retardancy.This study demonstrates that MOFs can be used as efficient thermal insulation and flame-retardant materials.It presents a pathway for the design of thermally insulating,superelastic fire-retardant nanocomposites based on MOFs and nanocellulose.

关 键 词：Metal-organic frameworks NANOCELLULOSE Superelastic aerogel Thermal insulation Fire retardancy 

分 类 号：O627[理学—有机化学] O648.17[理学—化学]