Improved mechanical property, thermal performance, flame retardancy and fire behavior of lignin-based rigid polyurethane foam nanocomposite

The current study aims at comparatively investigating the effect of apparent density on flame retardancy, thermal degradation and combustion behaviors of rigid polyurethane foam (RPUF), RPUF/ expandable graphite (EG) and RPUF/ ammonium polyphosphate (APP). A series of RPUF, RPUF/EG and RPUF/APP samples with different apparent densities (30, 60 and 90 kg/m3) were prepared. The flame retardancy, thermal degradation, and combustion behaviors of each sample were investigated. Limiting oxygen index (LOI) results indicated that increasing apparent density was beneficial to the flame retardancy of all foam systems. The effect of apparent density on the enhancement of flame retardancy followed the sequence of RPUF < RPUF/APP < RPUF/EG. Thermogravimetric analysis (TGA) results showed that an increase in the apparent density can cause more weight loss in the first degradation stage and less weight loss in the second degradation stage for all foam systems. The combustion behaviors also showed significant differences. The samples with a higher apparent density showed a longer duration of heat release and higher total heat release (THR). The findings in this study demonstrated that apparent density played an important role in flame retardancy, thermal degradation, and combustion behaviors of RPUF, which must be paid more attention in the studies of flame-retardant RPUF.

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Effects of Tung Oil-Based Polyols on the Thermal Stability, Flame Retardancy, and Mechanical Properties of Rigid Polyurethane Foam

Polymers ◽

10.3390/polym11010045 ◽

2018 ◽

Vol 11 (1) ◽

pp. 45 ◽

Cited By ~ 10

Author(s):

Wei Zhou ◽

Caiying Bo ◽

Puyou Jia ◽

Yonghong Zhou ◽

Meng Zhang

Keyword(s):

Thermal Stability ◽

Polyurethane Foam ◽

Flame Retardancy ◽

Covalent Bond ◽

Rigid Polyurethane Foam ◽

Limiting Oxygen Index ◽

Sem Micrographs ◽

Tung Oil ◽

Char Layer ◽

Ring Opening Reaction

A phosphorus-containing tung oil-based polyol (PTOP) and a silicon-containing tung oil-based polyol (PTOSi) were each efficiently prepared by attaching 9,10-dihydro-9-oxa-10-phosphaphenanthrene (DOPO) and dihydroxydiphenylsilane (DPSD) directly, respectively, to the epoxidized monoglyceride of tung oil (EGTO) through a ring-opening reaction. The two new polyols were used in the formation of rigid polyurethane foam (RPUF), which displayed great thermal stability and excellent flame retardancy performance. The limiting oxygen index (LOI) value of RPUF containing 80 wt % PTOP and 80 wt % PTOSi was 24.0% and 23.4%, respectively. Fourier transfer infrared (FTIR), Nuclear Magnetic Resonance (NMR) and thermogravimetric (TG) analysis revealed that DOPO and DPSD are linked to EGTO by a covalent bond. Interestingly, PTOP and PTOSi had opposite effects on Tg and the compressive strength of RPUF, where, with the appropriate loading, the compressive strengths were 0.82 MPa and 0.25 MPa, respectively. At a higher loading of PTOP and PTOSi, the thermal conductivity of RPUF increased while the RPUF density decreased. The scanning electron microscope (SEM) micrographs showed that the size and closed areas of the RPUF cells were regular. SEM micrographs of the char after combustion showed that the char layer was compact and dense. The enhanced flame retardancy of RPUF resulted from the barrier effect of the char layer, which was covered with incombustible substance.

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The synthesis and characterization of a DOPO derivative bearing an active terminal epoxy group: e-DOPO and its application in rigid polyurethane foam

Journal of Fire Sciences ◽

10.1177/0734904118812227 ◽

2018 ◽

Vol 37 (1) ◽

pp. 47-66 ◽

Cited By ~ 3

Author(s):

Daikun Jia ◽

Jiyu He ◽

Rongjie Yang

Keyword(s):

Thermogravimetric Analysis ◽

Polyurethane Foam ◽

Thermal Performance ◽

Oxygen Index ◽

Epoxy Group ◽

Polymer Materials ◽

Ionization Mass ◽

Rigid Polyurethane Foam ◽

Cone Calorimetry ◽

Limiting Oxygen Index

DOPO and its derivatives are excellent phosphorus-based flame retardants, which are applied to a series of polymer materials. In this article, a DOPO derivative bearing an active terminal epoxy group was synthesized using a non-solvent method. Fourier transform infrared spectroscopy, nuclear magnetic resonance, mass spectrometry, ultra-performance liquid chromatography, differential scanning calorimetry, thermogravimetric analysis, and viscosity measurements were performed to determine its molecular structure, purity, thermal performance, and fluidity. A possible fragmentation mechanism of the as-prepared DOPO derivative was analyzed using electron ionization mass spectrometer. All the results indicate that the synthesis was successful and the product had satisfactory purity and its initial decomposition temperature (T5%) under nitrogen and air atmosphere was 246°C and 240°C, respectively. Then, as a comparison with dimethyl methyl phosphonate, triethyl phosphate, and DOPO, e-DOPO was applied to a rigid polyurethane foam to investigate its effect on the flame retardancy, thermal stability, and cell morphology of polyurethane foam by limiting oxygen index, cone calorimetry, thermogravimetric analysis, and scanning electron microscopy. The results indicate that e-DOPO has a greater effect than DOPO and can effectively reduce the heat release and smoke release and improve the limiting oxygen index and thermal performance of the polyurethane foam. The cell size of the sample containing e-DOPO was more uniform.

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Enhanced thermal stability and flame retardancy of polyurethane foam composites with polybenzoxazine modified ammonium polyphosphates

RSC Advances ◽

10.1039/c5ra27256d ◽

2016 ◽

Vol 6 (16) ◽

pp. 13418-13425 ◽

Cited By ~ 25

Author(s):

Fubin Luo ◽

Kun Wu ◽

Mangeng Lu

Keyword(s):

Thermal Stability ◽

Thermal Behavior ◽

Polyurethane Foam ◽

Flame Retardancy ◽

Ammonium Polyphosphate ◽

Rigid Polyurethane Foam

The influence of polybenzoxazine modified ammonium polyphosphate (BMAPP) on the thermal behavior and flame retardancy of a rigid polyurethane foam (PU) are investigated using various techniques.

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