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

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 168 ◽  
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.

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

Materials ◽  
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.

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.

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.

Preparation and characterization of phenolic foam reinforced with expandable graphite and expanded graphite

2017 ◽  
Vol 54 (3) ◽  
pp. 545-559 ◽  
Author(s):  
Kejing Yu ◽  
Xia Luo ◽  
Menglei Wang ◽  
Kun Qian
Keyword(s):  
Mechanical Properties ◽  
Expanded Graphite ◽  
Expandable Graphite ◽  
Test Results ◽  
Compressive Test ◽  
Compression Performance ◽  
Phenolic Foam ◽  
Mean Diameter ◽  
The Mean

In this paper, two kinds of phenolic foams modified with expandable graphite and expanded graphite were prepared and the effect of particles on the mechanical properties and structure of the foams has been discussed. The mechanical properties, density and morphology of reinforced phenolic foams were studied. The images of scanning electron microscope showed that the size of the modified phenolic foams was smaller and more complete. The mean diameter of the expanded graphite-reinforced phenolic foams was smaller than that of the expandable graphite-reinforced phenolic foams due to the specific surface area of the expanded graphite. The compressive test results showed that the expandable graphite and expanded graphite could enhance the mechanical properties of the foams obviously. And the smaller cell size of the expanded graphite-reinforced foams provided them better mechanical properties. When the addition of the reinforcement reached to 0.8 wt%, the reinforced phenolic foams showed the best compression performance. The compressive strength and modulus with the 0.8 wt% expandable graphite were increased by 70% and 48% and that with the 0.8 wt% expanded graphite were increased by 80% and 69%.

scholarly journals Multifractal characterization of saprolite particle-size distributions after topsoil removal

Geoderma ◽  
2006 ◽  
Vol 134 (3-4) ◽  
pp. 373-385 ◽  
Author(s):  
J.G.V. Miranda ◽  
E. Montero ◽  
M.C. Alves ◽  
A. Paz González ◽  
E. Vidal Vázquez
Keyword(s):  
Particle Size ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Topsoil Removal

Preparation and Properties of Halogen-Free Flame Retardant Polyurethane Foams

2011 ◽  
Vol 418-420 ◽  
pp. 540-543 ◽  
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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