Flammability of Rigid Polyurethane Foams Blown with Pentane: Limiting Oxygen Index Data and Thermovision Characteristics

Flame-retardant rigid polyurethane foams incorporating N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol have been prepared. After adding N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol, the density and compressive strength of the polyurethane foams were seen to decrease. The flame retardancy of the polyurethane foams has been characterized by limiting oxygen index, upper limit–94, and cone calorimeter tests. The polyurethane foam with 2.27 wt% N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol gave a highest limiting oxygen index of 33.4%, and the peak heat release rate of polyurethane foam reduced to 19.5 kW/m2 from 47.6 kW/m2 of PU-0 without N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol. Upper limit–94 revealed N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol did not change the burning rating, and all polyurethane foams had passed V-0 rating. The thermal stability of polyurethane foams has been investigated by thermogravimetric analyzer. N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly increased the initial decomposition temperature of polyurethane foams and their residues. In addition, the morphology of residual char from the flame-retarded polyurethane foams after cone calorimeter tests has also been characterized by digital photographs. The results indicated that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol significantly enhanced the strength and compatibility of the char layer formed by the polyurethane foams. These results indicate that N,N-(pyromellitoyl)-bis-l-phenylalanine diacid ester glycol can improve both the quality and quantity of the char, which has a significant effect on the flame-retardant properties of the foam.

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

Letters in Organic Chemistry ◽

10.2174/1570178617666200224104336 ◽

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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Effects of Various Types of Expandable Graphite and Blackcurrant Pomace on the Properties of Viscoelastic Polyurethane Foams

Materials ◽

10.3390/ma14071801 ◽

2021 ◽

Vol 14 (7) ◽

pp. 1801

Author(s):

Rafał Oliwa ◽

Joanna Ryszkowska ◽

Mariusz Oleksy ◽

Monika Auguścik-Królikowska ◽

Małgorzata Gzik ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Structure ◽

Oxygen Index ◽

Polyurethane Foams ◽

Expandable Graphite ◽

Ftir Analysis ◽

Limiting Oxygen Index ◽

Peak Heat Release Rate ◽

Physical And Chemical ◽

Scanning Electron

We investigated the effect of the type and amount of expandable graphite (EG) and blackcurrant pomace (BCP) on the flammability, thermal stability, mechanical properties, physical, and chemical structure of viscoelastic polyurethane foams (VEF). For this purpose, the polyurethane foams containing EG, BCP, and EG with BCP were obtained. The content of EG varied in the range of 3–15 per hundred polyols (php), while the BCP content was 30 php. Based on the obtained results, it was found that the additional introduction of BCPs into EG-containing composites allows for an additive effect in improving the functional properties of viscoelastic polyurethane foams. As a result, the composite containing 30 php of BCP and 15 php of EG with the largest particle size and expanded volume shows the largest change in the studied parameters (hardness (H) = 2.65 kPa (+16.2%), limiting oxygen index (LOI) = 26% (+44.4%), and peak heat release rate (pHRR) = 15.5 kW/m2 (−87.4%)). In addition, this composite was characterized by the highest char yield (m600 = 17.9% (+44.1%)). In turn, the change in mechanical properties is related to a change in the physical and chemical structure of the foams as indicated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis.

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Influence of the Characteristics of Expandable Graphite on the Morphology, Thermal Properties, Fire Behaviour and Compression Performance of a Rigid Polyurethane Foam

Polymers ◽

10.3390/polym11010168 ◽

2019 ◽

Vol 11 (1) ◽

pp. 168 ◽

Cited By ~ 6

Author(s):

Pablo Acuña ◽

Zhi Li ◽

Mercedes Santiago-Calvo ◽

Fernando Villafañe ◽

Miguel Rodríguez-Perez ◽

...

Keyword(s):

Particle Size ◽

Oxygen Index ◽

Fire Behavior ◽

Polyurethane Foams ◽

Expandable Graphite ◽

Size Distributions ◽

Limiting Oxygen Index ◽

Compression Performance ◽

Cone Calorimeter Test

Three types of expandable graphite (EG) differing in particle size and expansion volume, are compared as flame retardant additives to rigid polyurethane foams (RPUFs). In this paper we discuss microstructure, thermal stability, fire behavior, and compression performance. We find that ell size distributions were less homogeneous and cell size was reduced. Furthermore, thermal conductivity increased along with EG loading. Thermogravimetric analysis (TGA) showed that EG only increased residue yield differently. The results indicate that a higher expansion of EG increased the limiting oxygen index (LOI) value, whereas a bigger particle size EG improved the rating of the vertical burning test (UL94). Results from the cone calorimeter test showed that a bigger particle size EG effectively reduced peak of heat release rate (pHRR). Furthermore, a higher expansion, led to a decrease in smoke production (TSP). The combination of both characteristics gives extraordinary results. The physical–mechanical characterization of the EG/RPUF foams revealed that their compression performance decreased slightly, mostly due to the effect of a bigger size EG.

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Preparation and Properties of Halogen-Free Flame Retardant Polyurethane Foams

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.540 ◽

2011 ◽

Vol 418-420 ◽

pp. 540-543 ◽

Cited By ~ 2

Author(s):

Ding Meng Chen ◽

Yi Ping Zhao ◽

Jia Jian Yan ◽

Li Chen ◽

Zhi Zhi Dong ◽

...

Keyword(s):

Flame Retardant ◽

Flame Retardants ◽

Oxygen Index ◽

Mechanical Analysis ◽

Polyurethane Foams ◽

Dimethyl Methylphosphonate ◽

Limiting Oxygen Index ◽

Layer Composite ◽

Halogen Free ◽

Thermal Stable

Polyurethane foams (PUFs) filled with several halogen-free flame retardants and composite halogen-free flame retardants were prepared. The flame retardant, thermal stable and mechanical properties of the PUFs were investigated. The results of limiting oxygen index (LOI) and thermogravimetric analysis (TGA) revealed that PUFs filled with dimethyl methylphosphonate (DMMP) had better flame retardancy compared with other flame retardants and DMMP degraded at a low temperature to form several phosphorated acids which accelerated the formation of char layer. Composite flame retardant of DMMP and melamine (MA) had a synergistic effect between phosphorus and nitrogen. The combination of DMMP and MA slightly altered the density of the PUFs. Results from the mechanical analysis revealed that with the increase in concentration of MA in the composite flame retardant of DMMP and MA, the tensile strength of PUFs reduced firstly and then increased up to a constant.

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Preparation and Characterization of Excellent Flame Retarded Rigid Polyurethane Foams

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.374-377.1563 ◽

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.

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Fire Phenomena of Rigid Polyurethane Foams

Polymers ◽

10.3390/polym10101166 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1166 ◽

Cited By ~ 15

Author(s):

Martin Günther ◽

Alessandra Lorenzetti ◽

Bernhard Schartel

Keyword(s):

Cross Sections ◽

Cone Calorimeter ◽

Morphological Changes ◽

Methodological Approach ◽

Thermal Inertia ◽

Polyurethane Foams ◽

Fire Behaviour ◽

Limiting Oxygen Index ◽

Rigid Polyurethane Foams ◽

Insight Into

Rigid polyurethane foams (RPUFs) typically exhibit low thermal inertia, resulting in short ignition times and rapid flame spread. In this study, the fire phenomena of RPUFs were investigated using a multi-methodological approach to gain detailed insight into the fire behaviour of pentane- and water-blown polyurethane (PUR) as well as pentane-blown polyisocyanurate polyurethane (PIR) foams with densities ranging from 30 to 100 kg/m3. Thermophysical properties were studied using thermogravimetry (TG); flammability and fire behaviour were investigated by means of the limiting oxygen index (LOI) and a cone calorimeter. Temperature development in burning cone calorimeter specimens was monitored with thermocouples inside the foam samples and visual investigation of quenched specimens’ cross sections gave insight into the morphological changes during burning. A comprehensive investigation is presented, illuminating the processes taking place during foam combustion. Cone calorimeter tests revealed that in-depth absorption of radiation is a significant factor in estimating the time to ignition. Cross sections examined with an electron scanning microscope (SEM) revealed a pyrolysis front with an intact foam structure underneath, and temperature measurement inside burning specimens indicated that, as foam density increased, their burning behaviour shifted towards that of solid materials. The superior fire performance of PIR foams was found to be based on the cellular structure, which is retained in the residue to some extent.

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Structure and Flame-Retardant Actions of Rigid Polyurethane Foams with Expandable Graphite

Polymers ◽

10.3390/polym11040686 ◽

2019 ◽

Vol 11 (4) ◽

pp. 686 ◽

Cited By ~ 4

Author(s):

Yongjun Chen ◽

Yuanfang Luo ◽

Xiaohui Guo ◽

Lijuan Chen ◽

Tiwen Xu ◽

...

Keyword(s):

Flame Retardancy ◽

Photoelectron Spectroscopy ◽

Oxygen Index ◽

Optical Microscope ◽

Carbon Layer ◽

Polyurethane Foams ◽

Limit Oxygen Index ◽

Expandable Graphite ◽

Rigid Polyurethane Foams ◽

Blending Method

In this paper, rigid polyurethane foams that were filled with expandable graphite (RPUF/EG) composites were prepared by the liquid blending method, and then the structure and flame retardancy performance of materials were investigated through optical microscope, scanning electron microscope, limit oxygen index, cone calorimeter, thermogravimetric analysis coupled to fourier transform infrared spectrum, and X-ray photoelectron spectroscopy. The results showed that a large number of EG could be good to the exhibition of flame retardancy of RPUF, where the optimal material was found at loading 15 phr EG that showed an increased limit oxygen index value and a decreased calorific or fuming value. TGA coupled FTIR and XPS revealed that EG could disassembled before RPUF under heating treatment, and it could form a pyknotic and enahnced residual carbon layer on RPUF surface after the fire, which restricted the transfer of gas, like oxygen or heat into PU matrix, finally resulting in the promotion of flame retardancy of RPUF.

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Bio-Based Rigid Polyurethane Foams Modified with Phosphorus Flame Retardants

Polymers ◽

10.3390/polym14010102 ◽

2021 ◽

Vol 14 (1) ◽

pp. 102

Author(s):

Marcin Zemła ◽

Aleksander Prociak ◽

Sławomir Michałowski

Keyword(s):

Rapeseed Oil ◽

Flame Retardants ◽

Thermal Conductivity Coefficient ◽

Oxygen Index ◽

Cell Structure ◽

Polyurethane Foams ◽

Triethyl Phosphate ◽

Rigid Polyurethane Foams ◽

Foaming Process ◽

Cone Calorimeter Test

Rigid polyurethane foams (RPURF) containing a bio-polyol from rapeseed oil and different phosphorus-based flame retardants were obtained. Triethyl phosphate (TEP), dimethyl propane phosphonate (DMPP) and cyclic phosphonates Addforce CT 901 (20 parts per hundred polyol by weight) were used in the synthesis of RPURF. The influence of used flame retardants on foaming process, cell structure, and physical–mechanical properties as well as flammability of RPURF were examined. The addition of flame retardants influenced the parameters of the cellular structure and decreased compressive strength. All obtained foam materials had a low thermal conductivity coefficient, which allows them to be used as thermal insulation. The research results of bio-based RPURF were compared with foams obtained without bio-polyol. All modified materials had an oxygen index above 21 vol%; therefore, they can be classified as self-extinguishing materials. The analysis of parameters obtained after the cone calorimeter test showed that the modified RPURF have a lower tendency to fire development compared to the reference foams, which was particularly noticeable for the materials with the addition of DMPP.

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The Effect of Soluble Ammonium Polyphosphate on the Properties of Water Blown Semirigid Polyurethane Foams

Advances in Materials Science and Engineering ◽

10.1155/2017/5282869 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Weiguo Yao ◽

Hanmo Wang ◽

Dongbo Guan ◽

Tao Fu ◽

Tianqi Zhang ◽

...

Keyword(s):

Mechanical Property ◽

Fourier Transform ◽

Flame Retardant ◽

Oxygen Index ◽

Degradation Mechanism ◽

Polyurethane Foams ◽

Ammonium Polyphosphate ◽

Limiting Oxygen Index ◽

Flame Retardant Property ◽

Blowing Agent

Soluble ammonium polyphosphate (SAPP) is employed to prepare flame retardant semirigid polyurethane foam (SPUF) using water as blowing agent. The flame retardant property of SPUF is evaluated by limiting oxygen index (LOI) and horizontal burning test. Also the thermal degradation mechanism is studied by TG and Fourier transform infrared (FTIR). The results show that, with the increase of the content of SAPP, flame retardant property of SPUF improves obviously as the LOI value increases and the horizontal burning rate decreases. And residual char is increased up to 20% with 19 wt% SAPP. Moreover, the mechanical property of SPUF is enhanced dramatically.

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