Investigation Of Effects Of Two Flame Retardants On The Fire Characterisit Ics Of Flexible Poly Ether Foam

CHAPTER THREE
EXPERIMENTAL
3.1    Materials and Methods
The materials include:
1.    Polyol
2.    Toluene diisocynate (TDI)
3.    Silicone
4.    Dimethylethanol amine
5.    Water
6.    Stanous octate 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 .
3.1.1    Apparatus
Apparatus used for the experiment are:
1.    Carbolite muffle furnace, AAF 11/18 serial No: 20    – 501901
3.2    Methods
3.2.1    Polyurethane foam formulations
Marthar foams industries formula for foam production was used for the foam recipe. The quantity of raw mat erials used in the production of polyurethane foam were constant, only the concentration of flame retar dants were varied as shown in Table 4 below.
Table 4: Formulation for polyurethane retarded with melamine

DAME    =    Dimethyl amino ethanol
TDI    =    Toluene diisocyanate
Table 5:        Formulation for polyurethane retarded with    tri ammonium orthophosphate

FR b =    Flame retardant Tri ammonium Orthophosphate
A measured quantity of polyol ether was weighed into a mixer. Then a known quantity of the flame retardant was thoroughly mixed with water and poured in to the mixer. This was followed by the addition of silicone, DMAE (2 – dimethylamino ethanol) and tin (II) stannous octate and the mixtures stirred very well in one direction to obtain a homogenous mixture. A weighed quantity of TDI (Toluene diisocyanate) was finally added and the mixture was stirred very quickly and poured into a mould for rising and curing to take place. After the curing, the polyurethane foam produced was then removed from the mould.
The quantity of flame retardant sample use in the production of polyurethane foam varies from 5% , 10% , 15% , 20% , and 25% while the measurement of the raw materials were constant.
3.3    Preparation of the foam samples for characterization
Each sample of polyurethane foam was measured and cut in a rectangular piece of area 80cm2 (20cm x 4cm, thickness 3cm), the following tests were carried out using the samples.
3.3.1    Flame characteristic s
There are many ways of studying the flame characteristics of materials. These include flame propagation rate, after – glow time,    ignition    –    time,    flame    duration,    char    formation, limiting    oxygen        index        (LOI),    smoke        density,    and thermogravimetric analysis.        In this study we adopted only After – glow time, flame duration, ignition time, and flame propagation rate and % char for mation.
3.3.2    Determination of After glow time (AGT)
A piece of the foam sample was clamped vertically in a draught free room. The sample was ignited at the base by means of a cigarette lighter until it was burning freely. The flame was blown out and the time between the flame – out and the last visually perceptible glow recorded with a stop – watch [29]. This is the after glow time. The tests were carried out for five times and the average times in seconds were recorded for accuracy.