scholarly journals Expendable Graphite as an Efficient Flame-Retardant for Novel Partial Bio-Based Rigid Polyurethane Foams

2020 ◽  
Vol 6 (2) ◽  
pp. 27
Author(s):  
Felipe M. de Souza ◽  
Jonghyun Choi ◽  
Sanket Bhoyate ◽  
Pawan K. Kahol ◽  
Ram K. Gupta
Keyword(s):  
Flame Retardant ◽  
Cell Structure ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Ene Reaction ◽  
Flammability Test ◽  
Closed Cell ◽  
One Step ◽  
Cost Efficient ◽  
High Conversion Yield

The rigid polyurethane foam (PU) is a versatile material, used especially for construction and household applications. The current situation demands a facile, cost-efficient, and greener approach for developing the polyurethanes from bio-derived materials. In this study, we present a novel bio-polyol synthesized using carvone, an extract from caraway, spearmint, or dill seeds via facile thiol-ene reaction. Our one-step reaction uses a UV irradiation to allow the room temperature conversion of the carvone to a high purity bio-polyol, as confirmed from the standard analytical characterizations. The hydroxyl number of 365 mg KOH/g close to its theoretical limit confirms the high conversion yield of the polyol for rigid PU synthesis. To overcome the flammability issues in PU, expandable graphite (EG) powder was used as an additive flame-retardant during the synthesis step. The resulting foams with EG maintained the uniform closed cell structure (>95%) with a high compression strength of 175 kPa. The addition of EG in PU results in the formation of a protective char layer during the flammability test and reduces the weight loss from 40.70% to 3.55% and burning time from 87 to 11 s. Our results confirm that the carvone-based polyol can be a novel alternative to the petroleum polyols for an industrial-scale application.

scholarly journals Novel Biobased Polyol Using Corn Oil for Highly Flame-Retardant Polyurethane Foams

2019 ◽  
Vol 5 (1) ◽  
pp. 13 ◽  
Author(s):  
Sneha Ramanujam ◽  
Camila Zequine ◽  
Sanket Bhoyate ◽  
Brooks Neria ◽  
Pawan Kahol ◽  
...  
Keyword(s):  
Heat Release ◽  
Flame Retardant ◽  
Corn Oil ◽  
Gel Permeation Chromatography ◽  
Polyurethane Foams ◽  
Cell Content ◽  
Ene Reaction ◽  
Closed Cell ◽  
Improved Stability ◽  
Flame Retardant Properties

A novel bio-based polyol was synthesized using corn oil and 2-mercaptoethanol via thiol-ene reaction as an alternative to petroleum-based polyol for the synthesis of polyurethane foams. The polyol was analyzed using wet chemical techniques to obtain hydroxyl number and viscosity. Infrared spectroscopy and gel permeation chromatography were used to confirm the structural properties of the foams. Flame-retardant polyurethane foams were prepared by the addition of different concentrations of dimethyl methyl phosphonate (DMMP) in final foam composition. The effect of DMMP on the thermo-mechanical properties of the polyurethane foams was analyzed. The TGA analysis showed improved stability of the final char with addition of DMMP in the foams. All the foams maintained a well-defined cellular structure and over 95% of closed cell content. The horizontal burning test showed reduced burning time and weight loss from 115 s and 38 wt.% for the neat foams, to 3.5 s and 5.5 wt.% for DMMP-containing foams (1.94 wt.% P). The combustion test using cone calorimeter showed a considerable reduction in heat release rate and total heat release. Thus, our study shows that corn-oil based polyol can be used to produce renewable polyol for industrially producible rigid polyurethane foams. The addition of a small amount of DMMP could result in a significant reduction in the flame-retardant properties of the polyurethane foams.

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.

A facile strategy to fabricate microencapsulated expandable graphite as a flame-retardant for rigid polyurethane foams

2015 ◽  
Vol 132 (31) ◽  
pp. n/a-n/a ◽  
Author(s):  
Xiao-Liang Zhang ◽  
Hong-Ji Duan ◽  
Ding-Xiang Yan ◽  
Li-Quan Kang ◽  
Wei-Qin Zhang ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Polyurethane Foams ◽  
Expandable Graphite ◽  
Rigid Polyurethane Foams

Expandable Graphite For Halogen-Free Flame-Retardant of High-Density Rigid Polyurethane Foams

2005 ◽  
Vol 44 (7) ◽  
pp. 1323-1337 ◽  
Author(s):  
Lei Shi ◽  
Zhong-Ming Li ◽  
Ming-Bo Yang ◽  
Bo Yin ◽  
Qiu-Ming Zhou ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Polyurethane Foams ◽  
High Density ◽  
Expandable Graphite ◽  
Rigid Polyurethane Foams ◽  
Halogen Free

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.

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