The Experts below are selected from a list of 26895 Experts worldwide ranked by ideXlab platform

Liping Gao - One of the best experts on this subject based on the ideXlab platform.

  • thermal performance mechanical property and Fire Behavior of epoxy thermoset based on reactive phosphorus containing epoxy monomer
    Journal of Thermal Analysis and Calorimetry, 2017
    Co-Authors: Liping Gao, Guangyao Zheng, Xiaoan Nie, Yigang Wang
    Abstract:

    In this work, renewable diphenolic acid was used to prepare reactive phosphorus-containing epoxy monomer (PCDGEDP) and its chemical structure was characterized by FTIR, 1H-NMR and 31P-NMR spectra. Subsequently, PCDGEDP was reacted with diaminodiphenylmethane (DDM) to obtain phosphorus-containing PCDGEDP/DDM thermoset. The performances of corresponding thermoset in terms of thermal stability, mechanical property, combustion performance and Fire Behavior have been investigated in detail. It is worth noting that phosphorus-containing PCDGEDP/DDM thermoset showed high glass transition temperature (127 °C), good thermal stability with high mass residue (16.1 % at 700 °C) as well as good mechanical properties. Meanwhile, phosphorus-containing PCDGEDP/DDM thermoset exhibited improved flame retardant property with UL-94V-0 grade and high LOI value (29.6 %). Moreover, incorporating reactive phosphorus-containing epoxy monomer PCDGEDP into epoxy network can significantly decrease the heat release rate, total heat release, smoke produce rate, total smoke release and therefore enhance the Fire safety of epoxy thermoset during combustion. It is implying that incorporating rigid phenyldiphosphate structure into epoxy molecular backbone can impart flame retardancy and smoke suppression properties to epoxy thermoset. It is tightly related to its higher phosphorus content (3.3 %) and higher mass residue (18.53 %) of phosphorus-containing PCDGEDP/DDM thermoset.

  • Improved mechanical property, thermal performance, flame retardancy and Fire Behavior of lignin-based rigid polyurethane foam nanocomposite
    Journal of Thermal Analysis and Calorimetry, 2015
    Co-Authors: Liping Gao, Guangyao Zheng, Lihong Hu, Yonghong Zhou, Guodong Feng
    Abstract:

    Liquefied lignin-based polyol (LBP) was successfully obtained by liquefying calcium lignosulphonate with a polyhydroxy alcohol mixture, which can substitute 30 % petroleum-based polyether polyol to prepare rigid polyurethane foam (RPUF). In an effort to reduce the flammability and smoke release from RPUF, liquefied LBP in combination with commercial flame retardant polyol (FRP), polyurethane microencapsulated ammonium polyphosphate (MAPP) and organically modified layered double hydroxide (OLDH) were used to fabricate halogen-free flame retardant RPUF nanocomposite. The influences of incorporating LBP, FRP, MAPP and OLDH into RPUF on the thermal conductivity, mechanical property, thermal performance, flame retardancy and Fire Behaviors of RPUFs were comprehensively investigated. It is noteworthy that simultaneously incorporating LBP, FRP, MAPP and OLDH into RPUF can significantly improve the mechanical property, thermal performance, flame retardancy and Fire Behavior of RPUF. The improved flame retardancy and Fire Behavior of RPUF are attributable to combined effects among LBP, FRP, MAPP and OLDH in gas phase and condensed phase.

  • synergistic effect of expandable graphite diethyl ethylphosphonate and organically modified layered double hydroxide on flame retardancy and Fire Behavior of polyisocyanurate polyurethane foam nanocomposite
    Polymer Degradation and Stability, 2014
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Meng Zhang
    Abstract:

    Abstract Halogen-free flame-retarded rosin-based rigid PIR foam nanocomposites have been successfully prepared by in-situ polymerization, which were based on renewable rosin polyester polyol, halogen-free flame retardants (such as expandable graphite and diethyl ethylphosphonate) and organically-modified nanoclay (such as organically-modified montmorillonite or organically-modified layered double hydroxide). The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behavior of PIR foam nanocomposites were comprehensively investigated. Furthermore, potential synergistic effect between organically-modified nanoclay and flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam has been investigated in detail. X-ray diffraction and transmission electron microscopy studies confirmed that exfoliated structure of OMMT or OLDH in PIR-FR45-OMMT2.0 or PIR-FR45-OLDH3.0 nanocomposite. The flammability and compressive strength tests showed that PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed significantly improved flame retardancy and slightly enhanced mechanical property compared with neat PIR foam. At the same time, PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed relatively low thermal conductivity, which can meet requirement of engineering applications as insulating material. Furthermore, commonly OMMT showed no synergistic effect with flame retardants when dealing with Fire Behavior. However, OLDH showed synergistic effect with flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam. The reason is that OLDH can promote the formation of reinforced char layer, provide an effective barrier against heat and oxygen, release noncombustible gases, and simultaneously effectively suppress smoke and gases during the combustion process.

  • synergistic effect of expandable graphite melamine polyphosphate and layered double hydroxide on improving the Fire Behavior of rosin based rigid polyurethane foam
    Industrial Crops and Products, 2013
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Youli Xie
    Abstract:

    Abstract The halogen-free flame retardant rosin-based rigid polyurethane foams were successfully prepared based on renewable rosin polyester polyol, intumescent flame retardants (such as expandable graphite and melamine polyphosphate) and layered double hydroxide. The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behaviors of all RPUFs were comprehensively investigated. Furthermore, potential synergy between layered double hydroxide (LDH), expandable graphite (EG) and melamine polyphosphate (MPP) on Fire Behavior of rosin-based RPUF has been investigated in detail. XRD results showed that LDH is exfoliated and well dispersed in rosin-based RPUF. The results of SEM and thermal conductivity tests showed that adding intumescent flame retardants (such as EG and MPP) or further adding LDH into RPUF does not have significant influence on the cell structure and thermal conductivity of rosin-based RPUF. The results of TGA showed that adding EG, MPP or further adding LDH into RPUF decreases the initial decomposition temperature and the second-stage maximum-rate decomposition temperature of RPUF, while increases the char residue of RPUF at high temperature whether under N2 atmosphere or air atmosphere. Furthermore, it is noteworthy that simultaneously adding EG, MPP and LDH into RPUF can significantly improve the flame retardancy, mechanical property and Fire Behavior of rosin-based RPUF. The LOI value of EG10/MPP10/LDH3.0/RPUF sample increases from 19.1 to 28.0% compared to that of pure RPUF. The compressive strength and specific compressive strength (compressive strength/density) for EG10/MPP10/LDH3.0/RPUF sample in parallel direction increase about 8.3% and 7.1% compared to that of pure RPUF, respectively. The cone calorimeter test results showed that simultaneously adding EG, MPP and LDH into RPUF can significantly decrease the heat release rate (HRR), total heat release (THR) and smoke emission Behavior of RPUF sample. The average heat release rate (Av-HRR) and total heat release (THR) decrease about 32.5% and 5.2% compared to that of pure RPUF, respectively. The average smoke production rate (Av-SPR), average rate of smoke release (Av-RSR), average specific extinction area (Av-SEA), total smoke release (TSR) and CO/CO2 weight ratio of EG10/MPP10/LDH3.0/RPUF sample decrease about 26.9%, 25.5%, 2.7%, 0.8% and 16.7% compared to that of pure RPUF, respectively. These test results indicating that LDH has synergistic effect with intumescent flame retardants (such as EG and MPP) on improving the Fire Behavior of rosin-based rigid polyurethane foam.

Guodong Feng - One of the best experts on this subject based on the ideXlab platform.

  • Improved mechanical property, thermal performance, flame retardancy and Fire Behavior of lignin-based rigid polyurethane foam nanocomposite
    Journal of Thermal Analysis and Calorimetry, 2015
    Co-Authors: Liping Gao, Guangyao Zheng, Lihong Hu, Yonghong Zhou, Guodong Feng
    Abstract:

    Liquefied lignin-based polyol (LBP) was successfully obtained by liquefying calcium lignosulphonate with a polyhydroxy alcohol mixture, which can substitute 30 % petroleum-based polyether polyol to prepare rigid polyurethane foam (RPUF). In an effort to reduce the flammability and smoke release from RPUF, liquefied LBP in combination with commercial flame retardant polyol (FRP), polyurethane microencapsulated ammonium polyphosphate (MAPP) and organically modified layered double hydroxide (OLDH) were used to fabricate halogen-free flame retardant RPUF nanocomposite. The influences of incorporating LBP, FRP, MAPP and OLDH into RPUF on the thermal conductivity, mechanical property, thermal performance, flame retardancy and Fire Behaviors of RPUFs were comprehensively investigated. It is noteworthy that simultaneously incorporating LBP, FRP, MAPP and OLDH into RPUF can significantly improve the mechanical property, thermal performance, flame retardancy and Fire Behavior of RPUF. The improved flame retardancy and Fire Behavior of RPUF are attributable to combined effects among LBP, FRP, MAPP and OLDH in gas phase and condensed phase.

  • synergistic effect of expandable graphite diethyl ethylphosphonate and organically modified layered double hydroxide on flame retardancy and Fire Behavior of polyisocyanurate polyurethane foam nanocomposite
    Polymer Degradation and Stability, 2014
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Meng Zhang
    Abstract:

    Abstract Halogen-free flame-retarded rosin-based rigid PIR foam nanocomposites have been successfully prepared by in-situ polymerization, which were based on renewable rosin polyester polyol, halogen-free flame retardants (such as expandable graphite and diethyl ethylphosphonate) and organically-modified nanoclay (such as organically-modified montmorillonite or organically-modified layered double hydroxide). The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behavior of PIR foam nanocomposites were comprehensively investigated. Furthermore, potential synergistic effect between organically-modified nanoclay and flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam has been investigated in detail. X-ray diffraction and transmission electron microscopy studies confirmed that exfoliated structure of OMMT or OLDH in PIR-FR45-OMMT2.0 or PIR-FR45-OLDH3.0 nanocomposite. The flammability and compressive strength tests showed that PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed significantly improved flame retardancy and slightly enhanced mechanical property compared with neat PIR foam. At the same time, PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed relatively low thermal conductivity, which can meet requirement of engineering applications as insulating material. Furthermore, commonly OMMT showed no synergistic effect with flame retardants when dealing with Fire Behavior. However, OLDH showed synergistic effect with flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam. The reason is that OLDH can promote the formation of reinforced char layer, provide an effective barrier against heat and oxygen, release noncombustible gases, and simultaneously effectively suppress smoke and gases during the combustion process.

  • synergistic effect of expandable graphite melamine polyphosphate and layered double hydroxide on improving the Fire Behavior of rosin based rigid polyurethane foam
    Industrial Crops and Products, 2013
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Youli Xie
    Abstract:

    Abstract The halogen-free flame retardant rosin-based rigid polyurethane foams were successfully prepared based on renewable rosin polyester polyol, intumescent flame retardants (such as expandable graphite and melamine polyphosphate) and layered double hydroxide. The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behaviors of all RPUFs were comprehensively investigated. Furthermore, potential synergy between layered double hydroxide (LDH), expandable graphite (EG) and melamine polyphosphate (MPP) on Fire Behavior of rosin-based RPUF has been investigated in detail. XRD results showed that LDH is exfoliated and well dispersed in rosin-based RPUF. The results of SEM and thermal conductivity tests showed that adding intumescent flame retardants (such as EG and MPP) or further adding LDH into RPUF does not have significant influence on the cell structure and thermal conductivity of rosin-based RPUF. The results of TGA showed that adding EG, MPP or further adding LDH into RPUF decreases the initial decomposition temperature and the second-stage maximum-rate decomposition temperature of RPUF, while increases the char residue of RPUF at high temperature whether under N2 atmosphere or air atmosphere. Furthermore, it is noteworthy that simultaneously adding EG, MPP and LDH into RPUF can significantly improve the flame retardancy, mechanical property and Fire Behavior of rosin-based RPUF. The LOI value of EG10/MPP10/LDH3.0/RPUF sample increases from 19.1 to 28.0% compared to that of pure RPUF. The compressive strength and specific compressive strength (compressive strength/density) for EG10/MPP10/LDH3.0/RPUF sample in parallel direction increase about 8.3% and 7.1% compared to that of pure RPUF, respectively. The cone calorimeter test results showed that simultaneously adding EG, MPP and LDH into RPUF can significantly decrease the heat release rate (HRR), total heat release (THR) and smoke emission Behavior of RPUF sample. The average heat release rate (Av-HRR) and total heat release (THR) decrease about 32.5% and 5.2% compared to that of pure RPUF, respectively. The average smoke production rate (Av-SPR), average rate of smoke release (Av-RSR), average specific extinction area (Av-SEA), total smoke release (TSR) and CO/CO2 weight ratio of EG10/MPP10/LDH3.0/RPUF sample decrease about 26.9%, 25.5%, 2.7%, 0.8% and 16.7% compared to that of pure RPUF, respectively. These test results indicating that LDH has synergistic effect with intumescent flame retardants (such as EG and MPP) on improving the Fire Behavior of rosin-based rigid polyurethane foam.

Guangyao Zheng - One of the best experts on this subject based on the ideXlab platform.

  • thermal performance mechanical property and Fire Behavior of epoxy thermoset based on reactive phosphorus containing epoxy monomer
    Journal of Thermal Analysis and Calorimetry, 2017
    Co-Authors: Liping Gao, Guangyao Zheng, Xiaoan Nie, Yigang Wang
    Abstract:

    In this work, renewable diphenolic acid was used to prepare reactive phosphorus-containing epoxy monomer (PCDGEDP) and its chemical structure was characterized by FTIR, 1H-NMR and 31P-NMR spectra. Subsequently, PCDGEDP was reacted with diaminodiphenylmethane (DDM) to obtain phosphorus-containing PCDGEDP/DDM thermoset. The performances of corresponding thermoset in terms of thermal stability, mechanical property, combustion performance and Fire Behavior have been investigated in detail. It is worth noting that phosphorus-containing PCDGEDP/DDM thermoset showed high glass transition temperature (127 °C), good thermal stability with high mass residue (16.1 % at 700 °C) as well as good mechanical properties. Meanwhile, phosphorus-containing PCDGEDP/DDM thermoset exhibited improved flame retardant property with UL-94V-0 grade and high LOI value (29.6 %). Moreover, incorporating reactive phosphorus-containing epoxy monomer PCDGEDP into epoxy network can significantly decrease the heat release rate, total heat release, smoke produce rate, total smoke release and therefore enhance the Fire safety of epoxy thermoset during combustion. It is implying that incorporating rigid phenyldiphosphate structure into epoxy molecular backbone can impart flame retardancy and smoke suppression properties to epoxy thermoset. It is tightly related to its higher phosphorus content (3.3 %) and higher mass residue (18.53 %) of phosphorus-containing PCDGEDP/DDM thermoset.

  • Improved mechanical property, thermal performance, flame retardancy and Fire Behavior of lignin-based rigid polyurethane foam nanocomposite
    Journal of Thermal Analysis and Calorimetry, 2015
    Co-Authors: Liping Gao, Guangyao Zheng, Lihong Hu, Yonghong Zhou, Guodong Feng
    Abstract:

    Liquefied lignin-based polyol (LBP) was successfully obtained by liquefying calcium lignosulphonate with a polyhydroxy alcohol mixture, which can substitute 30 % petroleum-based polyether polyol to prepare rigid polyurethane foam (RPUF). In an effort to reduce the flammability and smoke release from RPUF, liquefied LBP in combination with commercial flame retardant polyol (FRP), polyurethane microencapsulated ammonium polyphosphate (MAPP) and organically modified layered double hydroxide (OLDH) were used to fabricate halogen-free flame retardant RPUF nanocomposite. The influences of incorporating LBP, FRP, MAPP and OLDH into RPUF on the thermal conductivity, mechanical property, thermal performance, flame retardancy and Fire Behaviors of RPUFs were comprehensively investigated. It is noteworthy that simultaneously incorporating LBP, FRP, MAPP and OLDH into RPUF can significantly improve the mechanical property, thermal performance, flame retardancy and Fire Behavior of RPUF. The improved flame retardancy and Fire Behavior of RPUF are attributable to combined effects among LBP, FRP, MAPP and OLDH in gas phase and condensed phase.

  • synergistic effect of expandable graphite diethyl ethylphosphonate and organically modified layered double hydroxide on flame retardancy and Fire Behavior of polyisocyanurate polyurethane foam nanocomposite
    Polymer Degradation and Stability, 2014
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Meng Zhang
    Abstract:

    Abstract Halogen-free flame-retarded rosin-based rigid PIR foam nanocomposites have been successfully prepared by in-situ polymerization, which were based on renewable rosin polyester polyol, halogen-free flame retardants (such as expandable graphite and diethyl ethylphosphonate) and organically-modified nanoclay (such as organically-modified montmorillonite or organically-modified layered double hydroxide). The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behavior of PIR foam nanocomposites were comprehensively investigated. Furthermore, potential synergistic effect between organically-modified nanoclay and flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam has been investigated in detail. X-ray diffraction and transmission electron microscopy studies confirmed that exfoliated structure of OMMT or OLDH in PIR-FR45-OMMT2.0 or PIR-FR45-OLDH3.0 nanocomposite. The flammability and compressive strength tests showed that PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed significantly improved flame retardancy and slightly enhanced mechanical property compared with neat PIR foam. At the same time, PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed relatively low thermal conductivity, which can meet requirement of engineering applications as insulating material. Furthermore, commonly OMMT showed no synergistic effect with flame retardants when dealing with Fire Behavior. However, OLDH showed synergistic effect with flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam. The reason is that OLDH can promote the formation of reinforced char layer, provide an effective barrier against heat and oxygen, release noncombustible gases, and simultaneously effectively suppress smoke and gases during the combustion process.

  • synergistic effect of expandable graphite melamine polyphosphate and layered double hydroxide on improving the Fire Behavior of rosin based rigid polyurethane foam
    Industrial Crops and Products, 2013
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Youli Xie
    Abstract:

    Abstract The halogen-free flame retardant rosin-based rigid polyurethane foams were successfully prepared based on renewable rosin polyester polyol, intumescent flame retardants (such as expandable graphite and melamine polyphosphate) and layered double hydroxide. The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behaviors of all RPUFs were comprehensively investigated. Furthermore, potential synergy between layered double hydroxide (LDH), expandable graphite (EG) and melamine polyphosphate (MPP) on Fire Behavior of rosin-based RPUF has been investigated in detail. XRD results showed that LDH is exfoliated and well dispersed in rosin-based RPUF. The results of SEM and thermal conductivity tests showed that adding intumescent flame retardants (such as EG and MPP) or further adding LDH into RPUF does not have significant influence on the cell structure and thermal conductivity of rosin-based RPUF. The results of TGA showed that adding EG, MPP or further adding LDH into RPUF decreases the initial decomposition temperature and the second-stage maximum-rate decomposition temperature of RPUF, while increases the char residue of RPUF at high temperature whether under N2 atmosphere or air atmosphere. Furthermore, it is noteworthy that simultaneously adding EG, MPP and LDH into RPUF can significantly improve the flame retardancy, mechanical property and Fire Behavior of rosin-based RPUF. The LOI value of EG10/MPP10/LDH3.0/RPUF sample increases from 19.1 to 28.0% compared to that of pure RPUF. The compressive strength and specific compressive strength (compressive strength/density) for EG10/MPP10/LDH3.0/RPUF sample in parallel direction increase about 8.3% and 7.1% compared to that of pure RPUF, respectively. The cone calorimeter test results showed that simultaneously adding EG, MPP and LDH into RPUF can significantly decrease the heat release rate (HRR), total heat release (THR) and smoke emission Behavior of RPUF sample. The average heat release rate (Av-HRR) and total heat release (THR) decrease about 32.5% and 5.2% compared to that of pure RPUF, respectively. The average smoke production rate (Av-SPR), average rate of smoke release (Av-RSR), average specific extinction area (Av-SEA), total smoke release (TSR) and CO/CO2 weight ratio of EG10/MPP10/LDH3.0/RPUF sample decrease about 26.9%, 25.5%, 2.7%, 0.8% and 16.7% compared to that of pure RPUF, respectively. These test results indicating that LDH has synergistic effect with intumescent flame retardants (such as EG and MPP) on improving the Fire Behavior of rosin-based rigid polyurethane foam.

Yonghong Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Improved mechanical property, thermal performance, flame retardancy and Fire Behavior of lignin-based rigid polyurethane foam nanocomposite
    Journal of Thermal Analysis and Calorimetry, 2015
    Co-Authors: Liping Gao, Guangyao Zheng, Lihong Hu, Yonghong Zhou, Guodong Feng
    Abstract:

    Liquefied lignin-based polyol (LBP) was successfully obtained by liquefying calcium lignosulphonate with a polyhydroxy alcohol mixture, which can substitute 30 % petroleum-based polyether polyol to prepare rigid polyurethane foam (RPUF). In an effort to reduce the flammability and smoke release from RPUF, liquefied LBP in combination with commercial flame retardant polyol (FRP), polyurethane microencapsulated ammonium polyphosphate (MAPP) and organically modified layered double hydroxide (OLDH) were used to fabricate halogen-free flame retardant RPUF nanocomposite. The influences of incorporating LBP, FRP, MAPP and OLDH into RPUF on the thermal conductivity, mechanical property, thermal performance, flame retardancy and Fire Behaviors of RPUFs were comprehensively investigated. It is noteworthy that simultaneously incorporating LBP, FRP, MAPP and OLDH into RPUF can significantly improve the mechanical property, thermal performance, flame retardancy and Fire Behavior of RPUF. The improved flame retardancy and Fire Behavior of RPUF are attributable to combined effects among LBP, FRP, MAPP and OLDH in gas phase and condensed phase.

  • synergistic effect of expandable graphite diethyl ethylphosphonate and organically modified layered double hydroxide on flame retardancy and Fire Behavior of polyisocyanurate polyurethane foam nanocomposite
    Polymer Degradation and Stability, 2014
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Meng Zhang
    Abstract:

    Abstract Halogen-free flame-retarded rosin-based rigid PIR foam nanocomposites have been successfully prepared by in-situ polymerization, which were based on renewable rosin polyester polyol, halogen-free flame retardants (such as expandable graphite and diethyl ethylphosphonate) and organically-modified nanoclay (such as organically-modified montmorillonite or organically-modified layered double hydroxide). The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behavior of PIR foam nanocomposites were comprehensively investigated. Furthermore, potential synergistic effect between organically-modified nanoclay and flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam has been investigated in detail. X-ray diffraction and transmission electron microscopy studies confirmed that exfoliated structure of OMMT or OLDH in PIR-FR45-OMMT2.0 or PIR-FR45-OLDH3.0 nanocomposite. The flammability and compressive strength tests showed that PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed significantly improved flame retardancy and slightly enhanced mechanical property compared with neat PIR foam. At the same time, PIR-FR45-OMMT2.0 and PIR-FR45-OLDH3.0 nanocomposites possessed relatively low thermal conductivity, which can meet requirement of engineering applications as insulating material. Furthermore, commonly OMMT showed no synergistic effect with flame retardants when dealing with Fire Behavior. However, OLDH showed synergistic effect with flame retardants on improving the flame retardancy and Fire Behavior of rosin-based rigid PIR foam. The reason is that OLDH can promote the formation of reinforced char layer, provide an effective barrier against heat and oxygen, release noncombustible gases, and simultaneously effectively suppress smoke and gases during the combustion process.

  • synergistic effect of expandable graphite melamine polyphosphate and layered double hydroxide on improving the Fire Behavior of rosin based rigid polyurethane foam
    Industrial Crops and Products, 2013
    Co-Authors: Liping Gao, Guangyao Zheng, Guodong Feng, Yonghong Zhou, Youli Xie
    Abstract:

    Abstract The halogen-free flame retardant rosin-based rigid polyurethane foams were successfully prepared based on renewable rosin polyester polyol, intumescent flame retardants (such as expandable graphite and melamine polyphosphate) and layered double hydroxide. The morphology, thermal conductivity, mechanical property, thermal stability, flame retardancy and Fire Behaviors of all RPUFs were comprehensively investigated. Furthermore, potential synergy between layered double hydroxide (LDH), expandable graphite (EG) and melamine polyphosphate (MPP) on Fire Behavior of rosin-based RPUF has been investigated in detail. XRD results showed that LDH is exfoliated and well dispersed in rosin-based RPUF. The results of SEM and thermal conductivity tests showed that adding intumescent flame retardants (such as EG and MPP) or further adding LDH into RPUF does not have significant influence on the cell structure and thermal conductivity of rosin-based RPUF. The results of TGA showed that adding EG, MPP or further adding LDH into RPUF decreases the initial decomposition temperature and the second-stage maximum-rate decomposition temperature of RPUF, while increases the char residue of RPUF at high temperature whether under N2 atmosphere or air atmosphere. Furthermore, it is noteworthy that simultaneously adding EG, MPP and LDH into RPUF can significantly improve the flame retardancy, mechanical property and Fire Behavior of rosin-based RPUF. The LOI value of EG10/MPP10/LDH3.0/RPUF sample increases from 19.1 to 28.0% compared to that of pure RPUF. The compressive strength and specific compressive strength (compressive strength/density) for EG10/MPP10/LDH3.0/RPUF sample in parallel direction increase about 8.3% and 7.1% compared to that of pure RPUF, respectively. The cone calorimeter test results showed that simultaneously adding EG, MPP and LDH into RPUF can significantly decrease the heat release rate (HRR), total heat release (THR) and smoke emission Behavior of RPUF sample. The average heat release rate (Av-HRR) and total heat release (THR) decrease about 32.5% and 5.2% compared to that of pure RPUF, respectively. The average smoke production rate (Av-SPR), average rate of smoke release (Av-RSR), average specific extinction area (Av-SEA), total smoke release (TSR) and CO/CO2 weight ratio of EG10/MPP10/LDH3.0/RPUF sample decrease about 26.9%, 25.5%, 2.7%, 0.8% and 16.7% compared to that of pure RPUF, respectively. These test results indicating that LDH has synergistic effect with intumescent flame retardants (such as EG and MPP) on improving the Fire Behavior of rosin-based rigid polyurethane foam.

Scott L Stephens - One of the best experts on this subject based on the ideXlab platform.

  • disease fuels and potential Fire Behavior impacts of sudden oak death in two coastal california forest types
    Forest Ecology and Management, 2015
    Co-Authors: Alison B Forrestel, Benjamin S Ramage, Tadashi J Moody, Max A Moritz, Scott L Stephens
    Abstract:

    In the Douglas-fir (Pseudotsuga menziesii Mirb. Franco) and redwood (Sequoia sempervirens (D. Don) Endl.) forests of the central California coast, Sudden Oak Death (SOD) has led to landscape-scale mortality of tanoak (Notholithocarpus densiflorus (Hook. and Arn.) Manos, Cannon and S.H. Oh). As tanoak mortality progresses, fuel loads and potential Fire Behavior in these forests are changing. We documented increases in fuel loads over time in long-term monitoring plots in infested forests at Point Reyes National Seashore. Throughout the study, we observed a significant positive relationship between dead tanoak basal area and surface fuels. We used the Fire Behavior modeling program BehavePlus to compare potential Fire Behavior between diseased and healthy stands. Model outputs indicated the potential for longer flame lengths, higher rates of spread and more intense surface Fire in diseased stands. The potential for increased Fire intensity in diseased redwood and Douglas-fir forests may create additional challenges for Fire and natural resources managers and may affect the ecology of these forests into the future.

  • silvicultural and reserve impacts on potential Fire Behavior and forest conservation twenty five years of experience from sierra nevada mixed conifer forests
    Biological Conservation, 2005
    Co-Authors: Scott L Stephens, Jason J Moghaddas
    Abstract:

    Most administrators and ecologists agree that reducing the levels of hazardous fuels on forests is essential to restore healthy watersheds and protect adjacent human communities. The current debate over the appropriateness, technique, and timing of treatments utilized to restore vegetation structure and composition is currently on-going at local, state, and national levels. To provide information for these forums, the efficacy of seven traditional silvicultural systems and two types of reserves used in the Sierra Nevada mixed conifer forests is evaluated in terms of vegetation structure, fuel bed characteristics, modeled Fire Behavior, and potential wildFire related mortality. The systems include old-growth reserve, young-growth reserve, thinning from below, individual tree selection, overstory removal, and four types of plantations. These are the most commonly used silvicultural systems and reserves on federal, state, and private lands in the western United States. Each silvicultural system or reserve had three replicates and varied in size from 15 to 25 ha; a systematic design of plots was used to collect tree and fuel information. The majority of the traditional silvicultural systems examined in this work (all plantation treatments, overstory removal, individual tree selection) did not effectively reduce potential Fire Behavior and effects, especially wildFire induced tree mortality at high and extreme Fire weather conditions. Overall, thinning from below, and old-growth and young-growth reserves were more effective at reducing predicted tree mortality.

  • experimental fuel treatment impacts on forest structure potential Fire Behavior and predicted tree mortality in a california mixed conifer forest
    Forest Ecology and Management, 2005
    Co-Authors: Scott L Stephens, Jason J Moghaddas
    Abstract:

    Abstract Fuel treatments have been suggested as a means to limit the size and intensity of wildFires but few experiments are available to analyze the effectiveness of different treatments. This paper presents information from a replicated, stand level experiment from mixed conifer forests in the north-central Sierra Nevada that investigated how control, mechanical (crown thinning, thinning from below followed, rotary mastication), prescribed Fire, and mechanical followed by prescribed Fire treatments affected fuels, forest structure, potential Fire Behavior, and modeled tree mortality at 80th, 90th, and 97.5th percentile Fire weather conditions. Fuels Management Analyst was used to model Fire Behavior and tree mortality. Thinning and mastication each reduced crown bulk density by approximately 19% in mechanical only and mechanical plus Fire treatments. Prescribed burning significantly reduced the total combined fuel load of litter, duff, 1, 10, 100, and 1000 h fuels by as much as 90%. This reduction significantly altered modeled Fire Behavior in both mechanical plus Fire and Fire only treatments in terms of Fireline intensity and predicted mortality. The prescribed Fire only and mechanical followed by prescribed Fire treatments resulted in the lowest average Fireline intensities, rate of spread, and predicted mortality. The control treatment resulted in the most severe modeled Fire Behavior and tree mortality. Mechanical only treatments were an improvement over controls but still resulted in tree mortality at severe Fire weather when compared with the treatments that included prescribed Fire. Restoration of mixed conifer ecosystems must include an examination of how proposed treatments affect Fire Behavior and effects. Variation in existing stand structures will require solutions that are site specific but the principals outlined in this work should help managers make better decisions.