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 ...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.展开更多
The mechanical properties of wood flour/high-density polyethylene composites(WPC)were improved by adding a small amount of nano-SiO_(2)to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO_(2)ne...The mechanical properties of wood flour/high-density polyethylene composites(WPC)were improved by adding a small amount of nano-SiO_(2)to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO_(2)network.The wood flour was modified with a fire retardant(a mixture of sodium octabonate and amidine urea phosphate)to improve its fire retardancy.The flexural properties,creep resistance,thermal expansion,and fire retardancy of the WPC were compared to a control(WPCCTRL)without nano-SiO_(2)or fire retardant.The flexural strength and modulus of the WPC containing only 0.55 wt.%nano-SiO_(2)were 6.6%and 9.1%higher than the control,respectively,while the creep strain and thermal expansion rate at 90°C were 33.8%and 13.6%lower,respectively.The cone calorimetry tests revealed that the nano-SiO_(2)network physically shielded the WPC,giving it lower heat release and smoke production rates.The thermal expansion was further decreased by incorporating fire retardants into the WPC,which showed the lowest total heat release and total smoke production and the highest mass retention.This study demonstrates a facile procedure for producing WPC with desired performances by forming a continuous honeycomb-like network by adding a small amount of nanoparticles.展开更多
Wastes from polypropylene(PP)packages are accumulating every year because it is one of the most widely consumed and short lifecycle products.This paper aims to develop low thermal conductive and fire-retardant materia...Wastes from polypropylene(PP)packages are accumulating every year because it is one of the most widely consumed and short lifecycle products.This paper aims to develop low thermal conductive and fire-retardant materials from post-consumer PP(pPP)packages.Ammonium polyphosphate(APP)and hollow glass microsphere(HGM)were further added to improve the fire retardancy and thermal conductivity of pPP.The influence of APP and HGM on the mechanical and thermal properties,fire retardancy and thermal conductivity of pPP were investigated and compared with that of virgin PP(vPP).HGM was constantly added at 5 wt%while the content of APP was varied from 5 to 20 wt%.Experimental results showed that the tensile and flexural strengths were reduced with increasing APP concentrations.A morphological study confirmed the poor interfacial adhesion and debonding of each component during the applied load.Formulations containing APP less than 10 wt%did not show a satisfying fire retardancy rating due to the long self-extinguishing time.Further flame dipping and cotton ignition were observed for these formulations.With 15 and 20 wt%APP,the fire rating was significantly improved from no rating to V-0.The conductive heat transfer coefficient(k)was reduced by the presence of HGM.Based on these results,the formulation with 15 and 20 wt%could be used as a low k,fire-retardant building material.展开更多
High flammability of polymers has become a major issue which has restricted its applications.Recently,highly crystalline materials and metal–organic frameworks(MOFs),which consisted of metal ions and organic linkers,...High flammability of polymers has become a major issue which has restricted its applications.Recently,highly crystalline materials and metal–organic frameworks(MOFs),which consisted of metal ions and organic linkers,have been intensively employed as novel fire retardants(FRs)for a variety of polymers(MOF/polymer).The MOFs possessed abundant transition metal species,fire-retardant elements and potential carbon source accompanied with the facile tuning of the structure and property,making MOF,its derivatives and MOF hybrids promising for fire retardancy research.The recent progress and strategies to prepare MOF-based FRs are emphasized and summarized.The fire retardancy mechanisms of MOF/polymer composites are explained,which may guide the future design for efficient MOF-based FRs.Finally,the challenges and prospects related to different MOFbased FRs are also discussed and aim to provide a fast and holistic overview,which is beneficial for researchers to quickly get up to speed with the latest development in this field.展开更多
Thermoplastic polyurethane(PU)elastomers have attracted significant attention because of their many important industrial applications.However,the creation of fire-retardant and anti-dripping PU elastomers has remained...Thermoplastic polyurethane(PU)elastomers have attracted significant attention because of their many important industrial applications.However,the creation of fire-retardant and anti-dripping PU elastomers has remained a grant challenge due to the lack of crosslinking and weak interchain interactions.Herein,we report a mechanically robust,biodegradable,fire-retardant,and anti-dripping biobased PU elastomer with excellent biodegradability using an abietic acid-based compound as hard segments and polycaprolactone diol(PCL)as soft segments,followed by physically crosslinking with cellulose nanocrystals(CNC)through dynamic hydrogen-bonding.The resultant elastomer shows the balanced mechanical and fire-retardant properties,e.g.,a tensile strength and break strain of 9.1 MPa and 560%,a self-extinguishing ability(V-0 rating in UL-94 testing),and an anti-dripping behavior.Moreover,the as-developed PU can be completely degraded in 1.0 wt.%lipase solution at 37℃ in 60 days,arising from the catalytic and wicking effect of CNC on PU chains.This work provides an innovative and versatile strategy for constructing robust,fire-retardant,anti-dripping,and biodegradable PU elastomers,which hold great promise for practical applications in electronic and automobile sectors.展开更多
Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy...Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity(Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon6 nanofiber.展开更多
A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene(PP)/organically modified montmorillonite(OMMT) nanocomposites.The investigation was focused on the e...A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene(PP)/organically modified montmorillonite(OMMT) nanocomposites.The investigation was focused on the effects of annealing temperature on the structural changes and protective layer formation.The decomposition of OMMT and degradation of PP/OMMT nanocomposites were characterized by means of thermogravimetric analysis(TGA).The structural evolution and composition change in the surface region of PP...展开更多
Wood-based functional materials have developed rapidly.But the flammability significantly limits its further application.To improve the flame retardancy,the balsa wood was delignified by NaClO2 solution to create a ce...Wood-based functional materials have developed rapidly.But the flammability significantly limits its further application.To improve the flame retardancy,the balsa wood was delignified by NaClO2 solution to create a cellulose scaffold,and then alternately immersed in CaCl_(2) ethanol solution and NaHCO3 aqueous solution under vacuum.The high porosity and wettability resulting from delignification benefited the following mineralization process,changing the thermal properties of balsa wood significantly.The organic-inorganic wood composite showed abundant CaCO_(3) spherical particles under scanning electron microscopy.The peak of the heat release rate of delignified balsa-CaCO_(3) was reduced by 33%compared to the native balsa,according to the cone calorimetric characterization.The flame test demonstrated that the mineralized wood was flame retardant and selfextinguish.Additionally,the mineralized wood also displayed lower thermal conductivity.This study developed a feasible way to fabricate a lightweight,fire-retardant,self-extinguishing,and heat-insulating wood composite,providing a promising route for the valuable application of cellulosic biomass.展开更多
文摘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.
基金supported by the National Key Research and Development Program of China(Nos.2019YFD1101204 and 2019YFD1101203)the National Natural Science Foundation of China(Nos.31870547 and 31901251)+3 种基金the Project funded by China Postdoctoral Science Foundation(No.2019M652919)the Research and Development Program in Key Areas of Guangdong Province(No.2020B020216002)the Project of Guangzhou Municipal Key Laboratory of Woody Biomass Functional New Materials(No.201905010005)the Project of Key Disciplines of Forestry Engineering of Bureau of Education of Guangzhou Municipality.
文摘The mechanical properties of wood flour/high-density polyethylene composites(WPC)were improved by adding a small amount of nano-SiO_(2)to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO_(2)network.The wood flour was modified with a fire retardant(a mixture of sodium octabonate and amidine urea phosphate)to improve its fire retardancy.The flexural properties,creep resistance,thermal expansion,and fire retardancy of the WPC were compared to a control(WPCCTRL)without nano-SiO_(2)or fire retardant.The flexural strength and modulus of the WPC containing only 0.55 wt.%nano-SiO_(2)were 6.6%and 9.1%higher than the control,respectively,while the creep strain and thermal expansion rate at 90°C were 33.8%and 13.6%lower,respectively.The cone calorimetry tests revealed that the nano-SiO_(2)network physically shielded the WPC,giving it lower heat release and smoke production rates.The thermal expansion was further decreased by incorporating fire retardants into the WPC,which showed the lowest total heat release and total smoke production and the highest mass retention.This study demonstrates a facile procedure for producing WPC with desired performances by forming a continuous honeycomb-like network by adding a small amount of nanoparticles.
基金supported by the Energy Conservation and Promotion Fund Office(Contract No.014/2562)in collaboration with Thailand Science Research and Innovation(TSRI)and Srinakharinwirot University(Contract No.034/2564).
文摘Wastes from polypropylene(PP)packages are accumulating every year because it is one of the most widely consumed and short lifecycle products.This paper aims to develop low thermal conductive and fire-retardant materials from post-consumer PP(pPP)packages.Ammonium polyphosphate(APP)and hollow glass microsphere(HGM)were further added to improve the fire retardancy and thermal conductivity of pPP.The influence of APP and HGM on the mechanical and thermal properties,fire retardancy and thermal conductivity of pPP were investigated and compared with that of virgin PP(vPP).HGM was constantly added at 5 wt%while the content of APP was varied from 5 to 20 wt%.Experimental results showed that the tensile and flexural strengths were reduced with increasing APP concentrations.A morphological study confirmed the poor interfacial adhesion and debonding of each component during the applied load.Formulations containing APP less than 10 wt%did not show a satisfying fire retardancy rating due to the long self-extinguishing time.Further flame dipping and cotton ignition were observed for these formulations.With 15 and 20 wt%APP,the fire rating was significantly improved from no rating to V-0.The conductive heat transfer coefficient(k)was reduced by the presence of HGM.Based on these results,the formulation with 15 and 20 wt%could be used as a low k,fire-retardant building material.
基金This research is partly supported by the scholarship from China Scholarship Council under the Grant CSC(201608060071).
文摘High flammability of polymers has become a major issue which has restricted its applications.Recently,highly crystalline materials and metal–organic frameworks(MOFs),which consisted of metal ions and organic linkers,have been intensively employed as novel fire retardants(FRs)for a variety of polymers(MOF/polymer).The MOFs possessed abundant transition metal species,fire-retardant elements and potential carbon source accompanied with the facile tuning of the structure and property,making MOF,its derivatives and MOF hybrids promising for fire retardancy research.The recent progress and strategies to prepare MOF-based FRs are emphasized and summarized.The fire retardancy mechanisms of MOF/polymer composites are explained,which may guide the future design for efficient MOF-based FRs.Finally,the challenges and prospects related to different MOFbased FRs are also discussed and aim to provide a fast and holistic overview,which is beneficial for researchers to quickly get up to speed with the latest development in this field.
基金support of the National Natural Science Foundation of China(Nos.32301545 and 32071712)the Jiangsu Key Laboratory of Biomass Energy and Materials(No.JSBEM-S-202312)the Australian Research Council(Nos.FT190100188 and LP230100278).
文摘Thermoplastic polyurethane(PU)elastomers have attracted significant attention because of their many important industrial applications.However,the creation of fire-retardant and anti-dripping PU elastomers has remained a grant challenge due to the lack of crosslinking and weak interchain interactions.Herein,we report a mechanically robust,biodegradable,fire-retardant,and anti-dripping biobased PU elastomer with excellent biodegradability using an abietic acid-based compound as hard segments and polycaprolactone diol(PCL)as soft segments,followed by physically crosslinking with cellulose nanocrystals(CNC)through dynamic hydrogen-bonding.The resultant elastomer shows the balanced mechanical and fire-retardant properties,e.g.,a tensile strength and break strain of 9.1 MPa and 560%,a self-extinguishing ability(V-0 rating in UL-94 testing),and an anti-dripping behavior.Moreover,the as-developed PU can be completely degraded in 1.0 wt.%lipase solution at 37℃ in 60 days,arising from the catalytic and wicking effect of CNC on PU chains.This work provides an innovative and versatile strategy for constructing robust,fire-retardant,anti-dripping,and biodegradable PU elastomers,which hold great promise for practical applications in electronic and automobile sectors.
基金the financial support provided by the Defence Research Development Organisation (DRDO),New Delhi,for this project (ERIPR/ER/0905103/M/01/1279)
文摘Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity(Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon6 nanofiber.
基金supported by the National Natural Science Foundation of China for the Outstanding Youth Fund (No.50525311)general project(No.50473029)the Fund for Creative Research Groups(No.50621302)
文摘A model experiment was done to clear the formation mechanism of protective layers during combustion of polypropylene(PP)/organically modified montmorillonite(OMMT) nanocomposites.The investigation was focused on the effects of annealing temperature on the structural changes and protective layer formation.The decomposition of OMMT and degradation of PP/OMMT nanocomposites were characterized by means of thermogravimetric analysis(TGA).The structural evolution and composition change in the surface region of PP...
基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040013)National Natural Science Foundation of China(22108088)State Key Laboratory of Pulp and Paper Engineering(202105)for the financial support of this work.
文摘Wood-based functional materials have developed rapidly.But the flammability significantly limits its further application.To improve the flame retardancy,the balsa wood was delignified by NaClO2 solution to create a cellulose scaffold,and then alternately immersed in CaCl_(2) ethanol solution and NaHCO3 aqueous solution under vacuum.The high porosity and wettability resulting from delignification benefited the following mineralization process,changing the thermal properties of balsa wood significantly.The organic-inorganic wood composite showed abundant CaCO_(3) spherical particles under scanning electron microscopy.The peak of the heat release rate of delignified balsa-CaCO_(3) was reduced by 33%compared to the native balsa,according to the cone calorimetric characterization.The flame test demonstrated that the mineralized wood was flame retardant and selfextinguish.Additionally,the mineralized wood also displayed lower thermal conductivity.This study developed a feasible way to fabricate a lightweight,fire-retardant,self-extinguishing,and heat-insulating wood composite,providing a promising route for the valuable application of cellulosic biomass.