Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane r...Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane rigid foams blown by water have serious defects,i.e.friability and resulting lower adhesion strength.Thus,the purpose of this study is to resolve the problems by chemical plastication.The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react.To prove the reaction when polyol-premix and polyisocyanate were mixed,the model composite was synthesized and analyzed by IR,NMR and ESI(MS).Furthermore,a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared.By testing impact strength and adhesion strength of the foams,the actual effect of adding maleate was obtained.展开更多
A bi-component alcoholysis agent containing propylene glycol(PG)and ethanolamine(ETA)was used to catalyst the degradation of the waste polyurethane rigid foam.The oligomer polyols obtained through degradation were use...A bi-component alcoholysis agent containing propylene glycol(PG)and ethanolamine(ETA)was used to catalyst the degradation of the waste polyurethane rigid foam.The oligomer polyols obtained through degradation were used as raw materials to produce recycled polyurethane rigid foam composites with lignin as reinforcing filler.The effect of alcoholysis mass ratio on degradation was investigated by analyzing the viscosity,hydroxyl content and chemical structure of the degradation products.The effect of lignin addition on the properties of regenerated polyurethane rigid foam were investigated by analyzing water absorption rate,compressive strength,porosity,thermal stability,thermal conductivity coefficient,morphology and thermal stability of the recycled polyurethane rigid foam.Results show that different mass ration of PG to ETA significantly affects the degradation of waste polyurethane rigid foam.Besides,only with the addition of appropriate amount of lignin,the regenerated polyurethane rigid foam composites can meet the Chinese national standard“rigid polyurethane foam for building thermal insulation”(GB/T21558-2008).At this point,the composite is with good mechanical and thermal prperties,including high compressive strength,excellent thermal insulation performance,complete cell morphology and good thermal stability.展开更多
The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in...The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer （NDJ-1 ）, universal testing machine （Instron3365）, s...Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer （NDJ-1 ）, universal testing machine （Instron3365）, scanning electron microscope （SEM） and differential scanning calorimeter （DSC）. The results show that the viscosity of polyether polyol increases exponentially from 62 mPa s to 6 000 mPa s with the increase of functionality from 2 to 5.6, respectively. The overall density of foam increases slightly from 31.7 kg/m^3 to 37.4 kg/m^3 with increasing functionality while core density exhibited little difference. Compressive strength of foam shows the similar behavior with density except for 2-functional sample. At the same time, dimensional stability becomes better with increasing functionality except for 5.6-functional foam that has worse stability than 4.8-functional foam. From the SEM results, the functionality is not an important factor in determining distribution of cell size of foam. According to the results of thermal analysis, the glass transition temperature （T） shifts to a higher temperature from 128.9 ℃ to 166.3 ℃ for the 2 to 5.6 functional foam, respectively.展开更多
The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in we...The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight.The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams.The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples.The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently.Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples.The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.展开更多
Biomass phytic acid has potential flame retardant value as the main form of phosphorus in plant seeds.In this study,phytate-based flame retardants aluminum phytate(PA-Al)and iron phytate(PA-Fe)were synthesized and cha...Biomass phytic acid has potential flame retardant value as the main form of phosphorus in plant seeds.In this study,phytate-based flame retardants aluminum phytate(PA-Al)and iron phytate(PA-Fe)were synthesized and characterized.Subsequently,they were introduced into rigid polyurethane foam(RPUF)as flame retardants by one-step water-blown method.The results indicated that RPUF/PA-Fe30 exhibited the highest char residue of 22.1 wt%,significantly higher than 12.4 wt%of RPUF.Cone calorimetry analysis showed that the total heat release(THR)of RPUF/PA-Al30 decreased by 17.0%and total smoke release(TSR)decreased by 22.0%compared with pure RPUF,which were the lowest,demonstrating a low fire risk and good smoke suppression.Thermogravimetric analysis-Fourier transform infrared spectrometer(TG-FTIR)implied the release intensity of flammable gases(hydrocarbons,esters)and toxic gases(isocyanate,CO,aromatic compounds,HCN)of composites was significantly reduced after the addition of PA-Fe.The analysis of char residue indicated that the RPUF composites formed a dense char layer with a high degree of graphitization after the addition of PA-Al/PA-Fe,endowing RPUF composites with excellent mass&heat transmission inhibition effect and fire resistance in the combustion process.展开更多
Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded ri...Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded rigid PVC foam composites reinforced with class C and class F fly ash. The mechanical properties: such as tensile and flexural strength of composites containing class C fly ash were superior to the composites containing class F fly ash particles. Composites containing 6 phr class C fly ash showed a 24% improvement in the tensile strength in comparison to a mere 0.5% increase in composites reinforced with class F fly ash. Similarly, the addition of 6 phr of class F fly ash to the PVC foam matrix resulted in a 5.74% decrease in the flexural strength, while incorporating the same amount of class C fly ash led to a 95% increase in flexural strength. The impact strength of the composites decreased as the amount of either type of fly ash increased in the composites indicating that fly ash particles improve the rigidity of the PVC foam composites. No significant changes were observed in the thermal properties of the composites containing either type of fly ash particles. However, the thermo-mechanical properties measured by DMA indicated a steep increase in the viscoelastic properties of composites reinforced with class C flyash. The microstructural properties studied by Scanning Electron Microscopy (SEM) confirmed that fly ash particles were mechanically interlocked in the PVC matrix with good interfacial interaction with the matrix. However, particle agglomeration and debonding was observed in composites reinforced with higher amounts of fly ash.展开更多
Rigid polyurethane foams were fabricated with five kinds of liquefied sugarcane bagasse polyols （LBP）. The foams derived from sugarcane bagasse were investigated by thermogravimetric analysis （TGA）, and the therma...Rigid polyurethane foams were fabricated with five kinds of liquefied sugarcane bagasse polyols （LBP）. The foams derived from sugarcane bagasse were investigated by thermogravimetric analysis （TGA）, and the thermal degradation data were analyzed using the Coast-Redfern method and Ozawa method to obtain the reaction order and activation energy. The results indicate that the sugarcane bagasse-foams exhibit an excellent heat-resistant property, whereas their pyrolysis procedures are quite complicated. The reaction as first order only takes place from 250 to 400 ℃, and the pyrolysis activation energies vary from 20 to 140 kJ/mol during the whole pyrolysis process.展开更多
This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were...This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were used to synthesize PU polyols. Addition of adipic acid (ADA) to polyol resulted in improvedthermal and viscoelastic properties of foam materials. ADA content was varied from 1 to 6 wt%. Results ofthe dynamic mechanical spectra indicate an increase of the storage modulus E′ and the loss modulus E″ inthe whole temperature range for specimens with higher loading of ADA. In addition, damping factor shiftedto higher temperatures, but damping intensity remained almost unaffected by the compositions. Scanningelectron microscopy of the foams’ cross sections testified that the average cells’ size of 110 mm was unaffectedby the ADA content in polyol.展开更多
文摘Water-blown polyurethane rigid foams are getting more and more attention,because the traditional blowing agent HCFC141b has already been abolished to prevent the ozone layer from destruction.However,the polyurethane rigid foams blown by water have serious defects,i.e.friability and resulting lower adhesion strength.Thus,the purpose of this study is to resolve the problems by chemical plastication.The maleate was added to polyol-premix containing water or to polyisocyanate,with both of which maleate does not react.To prove the reaction when polyol-premix and polyisocyanate were mixed,the model composite was synthesized and analyzed by IR,NMR and ESI(MS).Furthermore,a series of water-blown polyurethane rigid foams added different amount maleate were successfully prepared.By testing impact strength and adhesion strength of the foams,the actual effect of adding maleate was obtained.
文摘A bi-component alcoholysis agent containing propylene glycol(PG)and ethanolamine(ETA)was used to catalyst the degradation of the waste polyurethane rigid foam.The oligomer polyols obtained through degradation were used as raw materials to produce recycled polyurethane rigid foam composites with lignin as reinforcing filler.The effect of alcoholysis mass ratio on degradation was investigated by analyzing the viscosity,hydroxyl content and chemical structure of the degradation products.The effect of lignin addition on the properties of regenerated polyurethane rigid foam were investigated by analyzing water absorption rate,compressive strength,porosity,thermal stability,thermal conductivity coefficient,morphology and thermal stability of the recycled polyurethane rigid foam.Results show that different mass ration of PG to ETA significantly affects the degradation of waste polyurethane rigid foam.Besides,only with the addition of appropriate amount of lignin,the regenerated polyurethane rigid foam composites can meet the Chinese national standard“rigid polyurethane foam for building thermal insulation”(GB/T21558-2008).At this point,the composite is with good mechanical and thermal prperties,including high compressive strength,excellent thermal insulation performance,complete cell morphology and good thermal stability.
文摘The two kinds of rigid polyurethane （PU） foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight. The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams. The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples. The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently. Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples. The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
基金the Joint Research Foundation of CAS and Hebei Province,China(No.2004-015)
文摘Water blown rigid polyurethane foams with different functionality were prepared. The physical properties of rigid foams were measured with rotational viscometer （NDJ-1 ）, universal testing machine （Instron3365）, scanning electron microscope （SEM） and differential scanning calorimeter （DSC）. The results show that the viscosity of polyether polyol increases exponentially from 62 mPa s to 6 000 mPa s with the increase of functionality from 2 to 5.6, respectively. The overall density of foam increases slightly from 31.7 kg/m^3 to 37.4 kg/m^3 with increasing functionality while core density exhibited little difference. Compressive strength of foam shows the similar behavior with density except for 2-functional sample. At the same time, dimensional stability becomes better with increasing functionality except for 5.6-functional foam that has worse stability than 4.8-functional foam. From the SEM results, the functionality is not an important factor in determining distribution of cell size of foam. According to the results of thermal analysis, the glass transition temperature （T） shifts to a higher temperature from 128.9 ℃ to 166.3 ℃ for the 2 to 5.6 functional foam, respectively.
基金The key project of "11th Five-Year Plan" in Heilongjiang Province (No. GB06B501-3)
文摘The two kinds of rigid polyurethane(PU) foams were prepared with respectively adding the refined alkali lignin and alkali lignin modified by 3-chloro-1,2-epoxypropane to be instead of 15% of the polyether glycol in weight.The indexes of mechanical performance, apparent density, thermal stability and aging resistance were separately tested for the prepared PU foams.The results show that the mechanical property, thermal insulation and thermal stability for PU foam with modified alkali lignin are excellent among two kinds of PU foams and control samples.The additions of the refined alkali lignin and modified alkali lignin to PU foam have little effect on the natural aging or heat aging resistance except for decreasing hot alkali resistance apparently.Additionally, the thermal conductivity of modified alkali lignin PU foam is lowest among two kinds of PU foams and control samples.The alkali lignin PU foam modified by 3-chloro-1,2-epoxypropane could be applied in the heat preservation field.
基金This research was supported by National Key Research and Development Project(No.2017YFE0113200)National Natural Science Fund of China(Nos.51403004,U1833113).
文摘Biomass phytic acid has potential flame retardant value as the main form of phosphorus in plant seeds.In this study,phytate-based flame retardants aluminum phytate(PA-Al)and iron phytate(PA-Fe)were synthesized and characterized.Subsequently,they were introduced into rigid polyurethane foam(RPUF)as flame retardants by one-step water-blown method.The results indicated that RPUF/PA-Fe30 exhibited the highest char residue of 22.1 wt%,significantly higher than 12.4 wt%of RPUF.Cone calorimetry analysis showed that the total heat release(THR)of RPUF/PA-Al30 decreased by 17.0%and total smoke release(TSR)decreased by 22.0%compared with pure RPUF,which were the lowest,demonstrating a low fire risk and good smoke suppression.Thermogravimetric analysis-Fourier transform infrared spectrometer(TG-FTIR)implied the release intensity of flammable gases(hydrocarbons,esters)and toxic gases(isocyanate,CO,aromatic compounds,HCN)of composites was significantly reduced after the addition of PA-Fe.The analysis of char residue indicated that the RPUF composites formed a dense char layer with a high degree of graphitization after the addition of PA-Al/PA-Fe,endowing RPUF composites with excellent mass&heat transmission inhibition effect and fire resistance in the combustion process.
文摘Fly ash particles are usually spherical and based on their chemical composition;they are categorized into two classes: C and F. This study compares the microstructural, mechanical and thermal properties of extruded rigid PVC foam composites reinforced with class C and class F fly ash. The mechanical properties: such as tensile and flexural strength of composites containing class C fly ash were superior to the composites containing class F fly ash particles. Composites containing 6 phr class C fly ash showed a 24% improvement in the tensile strength in comparison to a mere 0.5% increase in composites reinforced with class F fly ash. Similarly, the addition of 6 phr of class F fly ash to the PVC foam matrix resulted in a 5.74% decrease in the flexural strength, while incorporating the same amount of class C fly ash led to a 95% increase in flexural strength. The impact strength of the composites decreased as the amount of either type of fly ash increased in the composites indicating that fly ash particles improve the rigidity of the PVC foam composites. No significant changes were observed in the thermal properties of the composites containing either type of fly ash particles. However, the thermo-mechanical properties measured by DMA indicated a steep increase in the viscoelastic properties of composites reinforced with class C flyash. The microstructural properties studied by Scanning Electron Microscopy (SEM) confirmed that fly ash particles were mechanically interlocked in the PVC matrix with good interfacial interaction with the matrix. However, particle agglomeration and debonding was observed in composites reinforced with higher amounts of fly ash.
基金Funded by Guangdong Provincial Natural Science Foundation (No.E06200692)Guangdong Provincial Scientific and Technological Project(No. 2006A20401001)
文摘Rigid polyurethane foams were fabricated with five kinds of liquefied sugarcane bagasse polyols （LBP）. The foams derived from sugarcane bagasse were investigated by thermogravimetric analysis （TGA）, and the thermal degradation data were analyzed using the Coast-Redfern method and Ozawa method to obtain the reaction order and activation energy. The results indicate that the sugarcane bagasse-foams exhibit an excellent heat-resistant property, whereas their pyrolysis procedures are quite complicated. The reaction as first order only takes place from 250 to 400 ℃, and the pyrolysis activation energies vary from 20 to 140 kJ/mol during the whole pyrolysis process.
文摘This article deals with the study of the viscoelastic and thermal properties of polyurethane (PU) rigid foamsfrom biobased and recycled components. Rapeseed oil (RO) and recycled poly(ethylene terephthalate)(PET) were used to synthesize PU polyols. Addition of adipic acid (ADA) to polyol resulted in improvedthermal and viscoelastic properties of foam materials. ADA content was varied from 1 to 6 wt%. Results ofthe dynamic mechanical spectra indicate an increase of the storage modulus E′ and the loss modulus E″ inthe whole temperature range for specimens with higher loading of ADA. In addition, damping factor shiftedto higher temperatures, but damping intensity remained almost unaffected by the compositions. Scanningelectron microscopy of the foams’ cross sections testified that the average cells’ size of 110 mm was unaffectedby the ADA content in polyol.
