Industrial Chemistry Project Topics

Investigation of Effects of Two Flame Retardants on the Fire Characterisit Ics of Flexible Poly Ether Foam

Investigation of Effects of Two Flame Retardants on the Fire Characterisit Ics of Flexible Poly Ether Foam

Investigation of Effects of Two Flame Retardants on the Fire Characterisitics of Flexible Poly Ether Foam

CHAPTER ONE

The objectives of the Study;

  • The effects of melamine and tri ammoniumorthophosphate on the fire characteristics of the flexible polyurethane foams were
  • The fire characteristics of  flexible  polyurethane  that was flame retarded with melamine was compared with that of flame retarded with t ri ammon ium orthophosphate .
  • The reduction  of   the  flammability of the flexible polyurethane foams was
  • The extent of the effects of the two flame retardants on the ignition behaviour of flexible  polyurethane  foams was established .

CHAPTER TWO

LITERATURE REVIEW

Fire, Pyrolyses and Combustion

Fire is the reaction involving fuel and oxygen that produces heat and light . It results from rapid chemical reaction between a fuel (wood,  gasoline) or  polymeric materials (plastic, cellulose) and oxygen. In order to produce fire a combustible materials and oxygen must be present and in contact  at sufficient high temperature to initiate combustion. Th e two substances (oxygen and fuel) must continue to be in contact for combustion to be sustained.

A flame is a gas phase combustion reaction which is able to propagate through space  [10]. Fire is a common term for combustion especially when out of control combustion refers to exothermic reaction in  any phase.  It usually       implies propagation and oxidation.  In  most  combustion  processes the exothermic stages occur in the gas  phase  regardless  of the  initial  phases  of  the  reactants.  Therefore , flames are associated with most combustion      processes. The combustibility  of  a   substance   depends  on   its  chemical composition  and physical state     [3,10] . For instance, if the source of oxygen is air, then the molecules of any flammable gas  escaping  into  the  air,  will mix with   oxygen molecules and at ignition temperature,  will  burn.  In  case  of  a  liquid, the flammable liquid must first be vapourized and its vapour mixed with oxygen, and it will burn. Similarly, solids must usually be liquefied  and  vapourized,  or  at lease reduced to small particles, with large surface area before it will burn.

Every   material  must  be   raised   to   its    specific ignition temperature before a fire will occur, though oxidation of the material may take place below this temperature. Oxidation normally  involve s atmospheric           oxygen,    but many  other oxidizers produce flames and some flames do not involves oxidation reactions. Above the ignition temperature, the heat of oxidation does not dissipate fast enough and  raises  the next area of unburned fuel to ignition temperature. Normally the ignition temperature of solids are higher than  those of the liquids.

When a part of any material is exposed to external source of heat, its temperature will rise as a result of heat transfer. As temperature progressively increases, a point is reached when enough thermal energy has been imbibed as to break bonds.

 

CHAPTER THREE

EXPERIMENTAL

Materials and Methods

The materials include:

  1. Polyol
  2. Toluenediisocynate (TDI)
  3. Silicone
  4. Dimethylethanol amine
  5. Water
  6. Stanousoctate or Tin II
  7. Melamine
  8. Tri ammonium orthophosphate

Material (1 – 6) above were all obtained from Marthar foams industries Ltd., Nkpor – Obosi Road, Onitsha Anambra State Nigeria.

Melamine and tri ammonium orthophosphate were bought from Laboratory of National Research Institute for Chemical Technology (NARICT), Zaria .

Apparatus

Apparatus used for the experiment are:

  • Carbolite muffle  furnace,  AAF  11/ 18 serial No: 20– 501901

Methods

Polyurethane foam formulations

Marthar  foams industries formula  for foam production was used for  the foam recipe. The quantity of raw materials used in the production of polyurethane foam were  constant,  only the concentration  of flame retardants were varied.

CHAPTER FOUR

RESULTS AND DISCUSSION

After Glow Time (AGT)

The results  of the  after glow time produced with the two  flame  retardants  are  shown  in   Table 6, 3 below . The incorporation of  these two   flame retardants into the  substrate substantially reduced AGT – as much as six – fold at 2.5pph melamine concentration. Glow is an exothermal oxidative combustion of material without a flame and is known to depend on quantity of carbonaceous char available   [47]. Thus, the higher the char, the longer the AGT values.  In the  Fig. 3 below, at all concentrations after glow is decreased with respect to untreated sample. The significance of this observation becomes clear if it is realized that in fire situation, what is most striking is the flame and that attracts fire combatants. There have been countless cases  when after the flame  have  been dowsed and everybody gone home, and the fire starting all over later. This scenario is because ; the   usually not perceptible glow was  not  extinguished. Of cause  , the longer the  AGT time, the higher the risk of  re-enlightenment of a fire. Obviously therefore, reduction of AGT is a very useful technique in fire chemistry.

CHAPTER FIVE

CONCLUSION

The following conclusion can be made from the results of the study.

The two flame retardants, melamine  and tri ammonium orthophosphate ,  were successfully  incorporated in the production of flexible polyurethane foams under the production  conditions of a commercial foam industry.

Hence, it  is  clear  that the two flame retardants are  suitable for producing commercial foams that are affordable and maintains the quality.

The two flame retardants are effective in  reducing the after – glow time (AGT), flame duration time and propagation rate properties . The reduction of these fire char5acterisitcis is paramount  to reduction  of  flammability of the polyurethane foam which leads to safety of lives and properties.

Dramatic increase in ignition time and charring percentage shown by t ri ammonium orthophosphate is evidence that its incorporation into polyurethane will delay burning on occasions of fire, t hereby increases time for safety of life and properties.

However,  melamine showed better impact for after-glow time and flame duration time, while triammoniumorthophosphate is preferred  for  reduction  of  ignition  time and  propagation rate due to  increase in high percentage charring.

RECOMMENDATION

  1. The two flame retardants are recommended for use for retarding commercial polyurethane foams, that will reduce the incident of fire and destruction of life and
  2. Tri ammonium ortho phosphate is preferred for retarding flexible polyurethane foams to
  3. The commercial foam industries that are not incorporating any flame retardants to their products, because of cost, can now start to make use of these two flame retardants because  of  its  availability and low

REFERENCES

  • National Fire Protection Association (2008) fire loss in US during  2005,   abridg ed   report  ( http:/ / usfa. gov/ statistic / National) ( Retrieved, February 28, 2010)
  • M. Avento, (1980), Flame Retardant , an Overview. Encyclop aedia of Chemical Technology Vol. 10, John Wiley & Sons. New York , pp 348 – 372.
  • N. Eboatu (1992) Fire, Flammability  and Fire Fighting . Anchor Ednal Press,  Lagos, p.25
  • Nguyen  Huy  (2008)  “Flame Reta rdants” Microsoft Student  (DVD), Redmond: WA: Microsoft Corporation 2007
  • Gum;  W.  Riese; and H. Ulrich, (1992), Reaction Polymers; Oxford University Press , New York, pp . 108 – 112.
  • Ulrich (1996) Chemistry  and Technology of Isocyanates;  John Wiley &  Sons ICN, New York, pp. 98– 100.
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