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 ◽  
...  

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.

2011 ◽  
Vol 374-377 ◽  
pp. 1563-1566
Author(s):  
An Zhen Zhang ◽  
Yi He Zhang

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.


2017 ◽  
Vol 35 (2) ◽  
pp. 99-117 ◽  
Author(s):  
Qianqiong Zhao ◽  
Congyan Chen ◽  
Ruilan Fan ◽  
Yong Yuan ◽  
Yalin Xing ◽  
...  

A halogen-free flame retardant containing nitrogen and phosphorus, 2-[anilino-(6-oxobenzo[c][2,1]benzoxaphosphinin-6-yl)methyl]phenol (PDOP), has been synthesized by reaction of benzo[c][2,1]benzoxaphosphinine-6-oxide (DOPO) with 2-( N-phenyliminomethyl)phenol. Halogen-free flame-retardant rigid polyurethane foams (RPUF-PDOP) were prepared using PDOP as a flame retardant. The flammability was investigated using limiting oxygen index, a vertical burning test (UL-94), and a cone calorimeter. When PDOP (10 wt%) as flame retardant was added to RPUF (RPUF-PDOP10%), the limiting oxygen index value was increased from 18% to 27%, and a UL-94 V-0 rating was achieved; meanwhile, the peak heat release rate, total heat release, and the average mass-loss rates of RPUF-PDOP10% were reduced from 246 to 207 kW m−2, from 26.9 to 21.0 MJ/m2, and from 0.043 to 0.033 g/s, respectively. Especially, the initial decomposition temperature of RPUF-PDOP10% was decreased from 228°C to 209°C. The final residual char from decomposition of RPUF-PDOP10% was significantly increased up to 35.6%. The addition of PDOP did not markedly decrease the mechanical properties of the resulting flame-retardant RPUFs.


1993 ◽  
Vol 11 (5) ◽  
pp. 442-456 ◽  
Author(s):  
Jun Zhang ◽  
Michael E. Hall ◽  
A. Richard Horrocks

This paper is the first in a series of four which investigates the burning behaviour and the influence of flame retardant species on the flam mability of fibre-forming polymer and copolymers of acrylonitrile. A pressed powdered polymer sheet technique is described that enables a range of polymer compositions in the presence and absence of flame retardants to be assessed for limiting oxygen index, burning rate and char residue deter minations. The method offers a rapid, reproducible and convenient means of screening possible flame retardant systems, and LOI values compare favourably with those of films and fabrics comprising the same polymeric type. Burning rates, however, are sensitive to changes in physical sample character such as form (film vs. powder sheet) and density. Thus the technique forms an excellent basis for the generation of burning data which will enable comprehensive studies of acrylic polymer flammability and flame retardancy to be undertaken.


2015 ◽  
Vol 30 (6) ◽  
pp. 816-826 ◽  
Author(s):  
Yiren Huang ◽  
Jianwei Yang ◽  
Zhengzhou Wang

Flame-retardant properties of ammonium polyphosphate (APP) and its two microcapsules, APP with a shell of melamine–formaldehyde (MF) resin (MFAPP) and APP with a shell of epoxy resin (EPAPP), were studied in styrene–butadiene–styrene (SBS). The results indicate that APP after the microencapsulation leads to an increase in limiting oxygen index in SBS compared with APP. When dipentaerythritol is incorporated into the SBS composites containing the APP microcapsules, a further improvement in flame retardancy of the composites is observed. The microencapsulation does not result in much improvement of mechanical properties. Moreover, the effect of a compatibilizer (SBS grafted with maleic anhydride) on flame-retardant and mechanical properties of SBS/APP composites was investigated.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2554 ◽  
Author(s):  
Zhi Geng ◽  
Shuaishuai Yang ◽  
Lianwang Zhang ◽  
Zhenzhen Huang ◽  
Qichao Pan ◽  
...  

Introducing fire-retardant additives or building blocks into resins is a widely adopted method used for improving the fire retardancy of epoxy composites. However, the increase in viscosity and the presence of insoluble additives accompanied by resin modification remain challenges for resin transfer molding (RTM) processing. We developed a robust approach for fabricating self-extinguishing RTM composites using unmodified and flammable resins. To avoid the effects on resin fluidity and processing, we loaded the flame retardant into tackifiers instead of resins. We found that the halogen-free flame retardant, a microencapsulated red phosphorus (MRP) additive, was enriched on fabric surfaces, which endowed the composites with excellent fire retardancy. The composites showed a 79.2% increase in the limiting oxygen index, a 29.2% reduction in heat release during combustion, and could self-extinguish within two seconds after ignition. Almost no effect on the mechanical properties was observed. This approach is simple, inexpensive, and basically applicable to all resins for fabricating RTM composites. This approach adapts insoluble flame retardants to RTM processing. We envision that this approach could be extended to load other functions (radar absorbing, conductivity, etc.) into RTM composites, broadening the application of RTM processing in the field of advanced functional materials.


2017 ◽  
Vol 54 (3) ◽  
pp. 561-576 ◽  
Author(s):  
Jacek Lubczak ◽  
Renata Lubczak

Thermally resistant polyurethane foams containing 1,3,5-triazine ring were modified with additive flame retardants. It has been found that addition of melamine, melamine polyphosphate, or isocyanurate at the foaming step resulted in reduction of foam flammability. The physical properties of flame-retardant modified foams were compared with those of non-modified foams. The obtained modified foams showed oxygen index 22.2–24.2 and were highly thermally resistant even at long lasting 200℃ temperature exposure.


2018 ◽  
Vol 36 (6) ◽  
pp. 535-545 ◽  
Author(s):  
Daikun Jia ◽  
Yi Tong ◽  
Jin Hu

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.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Bo Li ◽  
Jianxun Liu ◽  
Feng Han ◽  
Xiaoling Li ◽  
Liangying Li ◽  
...  

Improving the compatibility between flame retardant and asphalt is a difficult task due to the complex nature of the materials. This study explores a low dosage compound flame retardant and seeks to improve the compatibility between flame retardants and asphalt. An orthogonal experiment was designed taking magnesium hydroxide, ammonium polyphosphate, and melamine as factors. The oil absorption and activation index were tested to determine the effect of titanate on the flame retardant additive. The pavement performance test was conducted to evaluate the effect of the flame retardant additive. Oxygen index test was conducted to confirm the effect of flame retardant on flame ability of asphalt binder. The results of this study showed that the new composite flame retardant is more effective in improving the compatibility between flame retardant and asphalt and reducing the limiting oxygen index of asphalt binder tested in this study.


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