Effects of Expandable Graphite on the Flame-retardant and Mechanical Performances of Rigid Polyurethane Foams

2021 ◽  
Author(s):  
Xin-chao Wang ◽  
Ya-peng Sun ◽  
Jie Sheng ◽  
Tie Geng ◽  
Lih-Sheng (Tom) Turng ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Flame Retardant ◽  
Fire Resistance ◽  
Mass Density ◽  
Ignition Time ◽  
Thermo Gravimetric Analysis ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Gravimetric Analysis ◽  
Limiting Oxygen Index

Abstract Polyurethane foams (PUFs) are found everywhere in our daily life, but they suffer from poor fire resistance. In this study, expansible graphite (EG) as flame retardant was incorporated into PUFs to improve material fire resistance. With the presence of EGs in the PU matrix, bubble size in PUF became smaller as confirmed by the scanning electron microscopy (SEM). The mass density of PUFs is directly proportional to the content of EG additive. The compression strengths of EG0/PUF and EG30/PUF decrease from 0.51 MPa to 0.29 MPa. The FTIR analysis of RPUFs showed that the addition of EGs did not change the functional group structures of RPUFs. Thermo-gravimetric analysis (TGA) testing results showed that the carbon residue weight of EG30/PUF is higher than other PU composite foams. The combination of TGA and FTIR indicated that the EG addition did not change the thermal decomposition products of EG0/PUF, but effectively inhibited its thermal decomposition rate. Cone calorimeter combustion tests indicated that the peak of the heat release rate (PHRR) of EG30/PUF significantly decreased to 100.5 kW/m2 compared to 390.6 kW/m2 for EG0/PUF. The ignition time of EG/PUF composites also increased from 2 s to 11 s with incorporation of 30wt% EGs. The limiting oxygen index (LOI) and UL-94 standard tests show that the LOI of EG30/PUF can reach 55 vol%, and go through V-0 level. This study showed that adding EG into PU foams could significantly improve the thermal stability and flame retardancy properties of EG/PUF composites without significantly sacrificing material compression strength. The research results provide useful guidelines on industrial production and applications of PUFs.

Preparation and Characterization of Excellent Flame Retarded Rigid Polyurethane Foams

2011 ◽  
Vol 374-377 ◽  
pp. 1563-1566
Author(s):  
An Zhen Zhang ◽  
Yi He Zhang
Keyword(s):  
Flame Retardant ◽  
Flame Retardants ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Dimethyl Methylphosphonate ◽  
Limiting Oxygen Index ◽  
Rigid Polyurethane Foams ◽  
Foaming Process ◽  
Flame Retarded

Rigid polyurethane foams were excellent thermal insulation materials with widely used, which was highly flammable at the same time. In order to obtain safe application, flame retarded polyurethane foams were needed. In this paper, series flame retarded rigid polyurethane foams were prepared with loading different flame retardants such as ammonium polyphosphate, expandable graphite, red phosphorus, Tri (2-chloroethyl) phosphate and dimethyl methylphosphonate. The effects of flame retardants on the foaming-process and flame retardant property of the rigid polyurethane foams were investigated by otary viscometer and limiting oxygen index. The results showed that the combination of solid and liquid flame retardants was necessary to improve the flame retardant and different flame retardants played synergistic roles in rigid polyurethane foams. The limiting oxygen indexes of the foams could be up to 30wt% and 29.6% with 25wt% solid flame retardants and 10wt% liquid retardants, respectively.

Nacre-mimetic CH/MMT fabrication coating on PET fabric for improving anti-dripping performance

2020 ◽  
Vol 32 (6) ◽  
pp. 803-812
Author(s):  
Yinchun Fang ◽  
Xinhua Liu ◽  
Wenqing Fei
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Thermo Gravimetric Analysis ◽  
Original Research ◽  
Gravimetric Analysis ◽  
Experimental Basis ◽  
Limiting Oxygen Index ◽  
Content Type ◽  
Pet Fabric ◽  
Assembly Method

PurposePET fiber is widely used in many fields, such as clothing and decorative materials. However, the high flammability and dripping problem restrict its applications. It is vital for PET fiber to overcome these two main drawbacks for practical applications.Design/methodology/approachIn this paper nacre-mimetic flame retardant coating of chitosan (CH) and Montmorillonite (MMT) was fabricated on PET fabrics through the layer-by-layer assembly method. The flame retardancy and anti-dripping performance of the treated PET fabric were investigated.FindingsThe results of limiting oxygen index (LOI) value and vertical burning test revealed the anti-dripping performance of PET fabrics which was greatly improved, while the flame retardancy has not been improved. The dripping phenomena was eliminated when the CH/MMT bilayers were over 5 BL. Thermo gravimetric analysis (TGA) results revealed that nacre-mimetic coated CH/MMT bilayers on PET fabrics would promote the char formation both under nitrogen atmosphere and under air atmosphere indicating the obviously condensed phase flame retardant action. scanning electron microscopy (SEM) images of the char residues revealed that coated PET fabrics would promote the formation of char.Research limitations/implicationsHowever, the char was an unstable char which would further combust to change the thermal degradation and combustion process of PET fabric. Though PET fabric coated by this CH/MMT nacre-mimetic system had no flame retardancy, the anti-dripping performance was greatly improved. This research would provide experimental basis for improving the anti-dripping performance for thermoplastic materials.Originality/valueThis research is the original research for the flame retardant treatment by fabrication nacre-mimetic CH/MMT coating on PET fabric, which has not been reported previously. This research would provide experimental basis for improving the anti-dripping performance for thermoplastic polymer fabrics.

Coconut shell extract imparting multifunction properties to ligno-cellulosic material

2017 ◽  
Vol 47 (6) ◽  
pp. 1261-1290 ◽  
Author(s):  
Mangesh D Teli ◽  
Pintu Pandit ◽  
Santanu Basak
Keyword(s):  
Flame Retardant ◽  
Degradation Mechanism ◽  
Thermo Gravimetric Analysis ◽  
Coconut Shell ◽  
Phytochemical Analysis ◽  
Gravimetric Analysis ◽  
Cellulosic Material ◽  
Thermo Gravimetric ◽  
Limiting Oxygen Index ◽  
Jute Fabric

Flame retardant textiles are increasingly in demand. There have been a number of approaches by which textile material is made flame retardant. The plant extracts imparting such properties to lingo-cellulosic material has been studied in this work. The paper reports the application of green coconut ( Cocosnucifera Linn) shell extract which is a natural waste source onto jute fabric. The acidic coconut shell extract was applied in neutral and alkaline conditions on jute fabric in different concentrations. The emerging fabric showed good flame retardant properties which were measured by different standard flammability tests. The limiting oxygen index value found to increase by 48% after application of alkaline coconut shell extract as such and on concentrating the coconut shell extract, it was found to increase 81%. The thermo gravimetric behaviour and degradation mechanism were studied by using thermo gravimetric analysis in nitrogen atmosphere. The presence of different elements, chemical groups and the structural topography of the untreated and coconut shell extract-treated lingo-cellulosic fabric were analysed by attenuated total reflection-Fourier transform infrared, Scanning electron microscopy, energy dispersive X-ray analysis and phytochemical analysis tests. In addition to the flame retardant property, the treated fabric showed natural colour (measured by colour strength value) and antibacterial property against both gram positive and gram negative bacteria.

Preparation of Colloidal Antimony Pentoxide and Synergist Effect on Brominated Flame Retardant

2014 ◽  
Vol 1081 ◽  
pp. 165-170
Author(s):  
Li Yun Lin ◽  
Xiang Zhou ◽  
Ya Rong Wu
Keyword(s):  
Flame Retardant ◽  
Oxygen Index ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
Brominated Flame Retardant ◽  
Thermo Gravimetric ◽  
Simple Method ◽  
Limiting Oxygen Index ◽  
Experimental Parameters ◽  
Strength Retention

Colloidal Antimony Pentoxide was prepared through a simple method based on reflux oxidization system. Detailed investigations about the effects of experimental parameters on the colloid stability and size distribution of the final products were carried out. The use of the combination of a brominated flame retardant 2,3-dibromo-succinic anhydride (DBrFR) as the flame-retarding agent and colloidal antimony pentoxide (APO) as the synergist to reduce the flammability of PET/cotton blend fabric was also studied. The BFR was effective in reducing the flammability of the blended fabric whereas APO enhances the effectiveness of DBrFR due to bromine–antimony synergism. The limiting oxygen index (LOI) value and the breaking strength retention of PET/ cotton fabric treated with DBrFR and APO were studied and the thermal behaviors of different treated fabrics were investigated via thermo gravimetric analysis (TGA).

scholarly journals Vermiculite Filler Modified with Casein, Chitosan, and Potato Protein as a Flame Retardant for Polyurethane Foams

2021 ◽  
Vol 22 (19) ◽  
pp. 10825
Author(s):  
Karolina Miedzińska ◽  
Sylwia Członka ◽  
Anna Strąkowska ◽  
Krzysztof Strzelec
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Flame Retardant ◽  
Ignition Time ◽  
Polyurethane Foams ◽  
Flame Resistance ◽  
Potato Protein ◽  
Limiting Oxygen Index ◽  
Polyurethane Composites ◽  
The Impact

In this study, polyurethane (PU) composite foams were modified with 2 wt.% of vermiculite fillers, which were themselves modified with casein, chitosan, and potato protein. The impact of the fillers on selected properties of the obtained composites, including their rheological (foaming behavior, dynamic viscosity), thermal (temperature of thermal decomposition stages), flame-retardant (e.g., limiting oxygen index, ignition time, heat peak release), and mechanical properties (toughness, compressive strength (parallel and perpendicular), flexural strength) were investigated. Among all the modified polyurethane composites, the greatest improvement was noticed in the PU foams filled with vermiculite modified with casein and chitosan. For example, after the addition of modified vermiculite fillers, the foams’ compressive strength was enhanced by ~6–18%, their flexural strength by ~2–10%, and their toughness by ~1–5%. Most importantly, the polyurethane composites filled with vermiculite filler and modified vermiculite fillers exhibited improved flame resistance characteristics (the value of total smoke release was reduced by ~34%, the value of peak heat release was reduced by ~25%).

Synergistic effects of red phosphorus masterbatch with expandable graphite on the flammability and thermal stability of polypropylene/thermoplastic polyurethane blends

2019 ◽  
Vol 28 (3) ◽  
pp. 209-219 ◽  
Author(s):  
Na Wang ◽  
Lingtong Li ◽  
Yang Xu ◽  
Kun Zhang ◽  
Xiaolang Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heat Release ◽  
Flame Retardant ◽  
Synergistic Effects ◽  
Thermoplastic Polyurethane ◽  
Expandable Graphite ◽  
Gravimetric Analysis ◽  
Red Phosphorus ◽  
Limiting Oxygen Index ◽  
Ul 94

The flammability characterization and synergistic effects of red phosphorus masterbatch (RPM) with expandable graphite (EG) in flame-retardant polypropylene (PP)/thermoplastic polyurethane (TPU) composites are investigated by limiting oxygen index, UL-94 testing, cone calorimeter tests, thermal gravimetric analysis, Fourier transform infrared (FTIR), and scanning electron microscopy. The results show that the flame retardancy of PP/TPU/EG/RPM composites is greatly influenced by RPM. The synergistic effects between RPM and EG take place in the flame-retardant composites. The presence of RPM with EG decreases significantly the heat release rates and total heat release, and UL-94 V-0 rating is achieved when suitable amount of RPM substitutes for EG in the PP/TPU/EG/RPM composites. The T onset and T 10 wt% of the composites are improved because of the presence of RPM. The FTIR spectra show that the incorporation of RPM improves the thermo-oxidative stability of PP/TPU at higher temperatures. The morphological observations indicate the reinforcement of thermal stability, and flame-retardant performance is attributed to the compact and stable char layers promoted by RPM with EG acted as an effective heat barrier and thermal insulation.

Thermal Degradation Kinetics of a Intumescent Flame Retardant System for Halogen-Free Flame Retarded EVA

2012 ◽  
Vol 550-553 ◽  
pp. 2767-2772
Author(s):  
Xiu Yun Li ◽  
De Tian Liao ◽  
Han Bing Ma ◽  
Kang Lin Xu ◽  
An Bin Tang
Keyword(s):  
Thermal Degradation ◽  
Flame Retardant ◽  
Degradation Kinetics ◽  
Thermo Gravimetric Analysis ◽  
Intumescent Flame Retardant ◽  
Thermal Degradation Kinetics ◽  
Flame Retardance ◽  
Gravimetric Analysis ◽  
Heating Rates ◽  
Limiting Oxygen Index

An intumescent flame retardant (IFR) system containing phosphorus-silicon (EMPZR) and ammonium polyphosphate (APP) was used to improve the flame retardancy of poly(ethylene-co-vinyl acetate)(EVA). The influence of EMPZR contents on the flame retardance of EVA/EMPZR/APP composites has been studied. It was found that the reasonable mass ratio of EMPZR/APP in EVA/EMPZR/APP composites is 20/20, whose limiting oxygen index (LOI) value was improved from 19.0 for EVA to 28.6, and the burning grading reached to UL-94 V-0. The thermal behavior of EVA and IFR-EVA was investigated by dynamic thermo gravimetric analysis (TGA) at different heating rates and then the thermal degradation activation energies of EVA and IFR-EVA were determined by using Flynn-Wall-Ozawa method. Meanwhile, morphology of the char residue obtained from burning IFR-EVA in LOI test was studied through the scanning electron microscopy SEM observation, the rich compact char layer in which could explain the good flame retardance and the synergistic effect between EMPZR and APP.

scholarly journals The Synergistic Effect of Ionic Liquid-Modified Expandable Graphite and Intumescent Flame-Retardant on Flame-Retardant Rigid Polyurethane Foams

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3095 ◽  
Author(s):  
Yongjun Chen ◽  
Yuanfang Luo ◽  
Xiaohui Guo ◽  
Lijuan Chen ◽  
Demin Jia
Keyword(s):  
Thermal Decomposition ◽  
Ionic Liquid ◽  
Flame Retardant ◽  
Polyurethane Foams ◽  
Molecular Structures ◽  
Intumescent Flame Retardant ◽  
Expandable Graphite ◽  
Thermal Decomposition Mechanism ◽  
Rigid Polyurethane Foams ◽  
Synergistic Flame Retardant

In this study, a nitrogen–phosphorus intumescent flame-retardant 3-(N-diphenyl phosphate) amino propyl triethoxy silane (DPES), the ionic liquid (IL) of 1-butyl-3-methyl-imidazole phosphate, and a phosphorous-containing ionic liquid-modified expandable graphite (IL-EG), were synthesized, and their molecular structures were characterized. The flame-retardant rigid polyurethane foams (RPUFs) were compounded with synergistic flame-retardant IL-EG/DPES to study the effects of the combination IL-EG and DPES on the pore structure, mechanical properties, thermal decomposition behavior and thermal decomposition mechanism of RPUF. The results showed that IL-EG/DPES had good thermal stability, and an excellent expansibility and char yield. The flame-retardant RPUF, modified with IL-EG and DPES at the ratio of 1:1, had a relatively uniform pore size, the highest compressive strength, and an excellent flame-retardant performance due to the form interwoven hydrogen bonds between IL-EG and DPES, as well as the new synergistic flame-retardant coating on the RPUF surface to restrict the transfer of gas or heat into the PU matrix.

Preparation and Characterization of Soybean Oil-based Flame Retardant Rigid Polyurethane Foams Containing Phosphaphenanthrene Groups

2020 ◽  
Vol 17 (10) ◽  
pp. 760-771
Author(s):  
Qirui Gong ◽  
Niangui Wang ◽  
Kaibo Zhang ◽  
Shizhao Huang ◽  
Yuhan Wang
Keyword(s):  
Soybean Oil ◽  
Flame Retardant ◽  
Chemical Structure ◽  
Cell Structure ◽  
Polyurethane Foams ◽  
Limiting Oxygen Index ◽  
Rigid Polyurethane Foams ◽  
Degradation Activation Energy ◽  
Ft Ir

A phosphaphenanthrene groups containing soybean oil based polyol (DSBP) was synthesized by epoxidized soybean oil (ESO) and 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Soybean oil based polyol (HSBP) was synthesized by ESO and H2O. The chemical structure of DSBP and HSBP were characterized with FT-IR and 1H NMR. The corresponding rigid polyurethane foams (RPUFs) were prepared by mixing DSBP with HSBP. The results revealed apparent density and compression strength of RPUFs decreased with increasing the DSBP content. The cell structure of RPUFs was examined by scanning electron microscope (SEM) which displayed the cells as spherical or polyhedral. The thermal degradation and flame retardancy of RPUFs were investigated by thermogravimetric analysis, limiting oxygen index (LOI), and UL 94 vertical burning test. The degradation activation energy (Ea) of first degradation stage reduced from 80.05 kJ/mol to 37.84 kJ/mol with 80 wt% DSBP. The RUPF with 80 wt% DSBP achieved UL94 V-0 rating and LOI 28.3. The results showed that the flame retardant effect was mainly in both gas phase and condensed phase.

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