ABSTRACT
This work studied the effects of two flame retardants on
the fire characteristics of flexible polyether foam samples. Various
concentrations of two flame retardants melamine and tri ammonium orthophosphate
have been successfully incorporated into flexible polyurethane foam. Results of
the analyses carried out on the various foam samples showed that by appropriate
incorporation of the two flame retardants, the flammability properties (After
glow time (AGT), ignition time, flame duration time, flame propagation time and
percentage char) have been greatly improved through both condensed (solid)
phase and gas phase mechanisms specifically. The After glow time (AGT), flame
duration time and propagation rate were greatly reduced, while the ignition
time and percentage charring were increased with increase in concentration of
the two flame retardants. However, melamine showed better impact for reduction
of after glow time and flame duration time while tri ammonium orthophosphate is
preferred for increase in ignition time and reduction in flame propagation rate
with outstanding evidence of high percentage charring ability.
CHAPTER ONE
INTRODUCTION
1.1 Background
Fire is a world wild problem which claims lives and causes
significant loss of properties. Most of the immediate surroundings of man
consist of polymeric materials which are combustible materials. These include
clothes, furniture, construction materials, and interior decorations.
Generally, the interiors of homes, offices, vehicles, and packages are
decorated with foamed plastics. The constitution of foamable polymeric
materials made them liable to easy ignition and vigorous burning under right
conditions. Humans have always been plagued by unwanted fire, which usually
gulfed life and properties worth of millions of naira.
In addition to immediate fire risk posed by the polymeric materials
while burning, their combustion products often cause serious threat to human
health and environment. In United States between 1996 and 2005 it was reported
that an average of 3,932 human loss and another 20,919 injuries were as a
result of fire accidents [1].
Recently, on 9th
Oct 2009, along Enugu-Onitsha express road, over ten vehicles loaded full with
humans and property worth millions of naira were engulfed by fire. Therefore,
the need to seek efficient and affordable ways of reducing the flammability of
polymeric materials in our surroundings is of primary importance.
A flame is a rapid free radical, chain reaction of
volatile materials with oxygen in the air. It is actually the resultant flame
or fire that consumes life and properties. The term fire retardant (flame retardant)
describes materials that inhibit or resist flammability of polymers. In the
same vein a fire retardant chemical is used to denote a compound or mixture of
compounds that when added to, or incorporated chemically into polymers, serve
to slow down or hinder the ignition or growth of fire [2]. In other words, a
flame retardant chemical is therefore a compound or mixture of compounds which
when added to or chemically incorporated into a polymeric material,
substantially suppresses the ease of ignition and/or flame propagation [3].
The
above definitions of flame retardant denote that it generally either lower
ignition susceptibility or lower the flame propagation once the ignition has
occurred. The products on which flame retardants can be applied include
apparels, carpets, and rugs, construction materials (thermal) insulation foams,
wall coverings and composites to meet governmental regulations for buildings,
aircraft, auto mobiles. Flame retardants can be incorporated into a material
either as a reactive component or as an additive component. As a reactive, such
flame retardants are incorporated into the polymer structure of the plastics,
example, when polyurethane and polyamides are retarded with red phosphorus....
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