Advances in Ma terials Physics and Che mist ry, 2012, 2, 99-101
doi:10.4236/ampc.2012.24B027 Published Online December 2012 (htt p://www.SciR
Copyright © 2012 SciRes. AM PC
Increasing the Burned Time and Mechanical Prop er t ies with
New Mix As Flame Retardant Based in Hexametaphosphate
of Sodium and Borax in Textile 100% Acrylic Fabrics
M. Olvera-Gracia1, L. Mercado-Velazquez1, A.M. Paniagua-Mercado2
1Instituto Politécnico Nacional, ESIT Secci ón de estud ios de Posgra do e invest igación, Av. IPN, México
2Instituto Politécnico Nacional, ESFM - Departamento de Ciencia de Materiales, México
Received 2012
It has been worked with textil e fabrics of Acrylic 1 00% , that have as final u se the Tapestry, th is fabrics h ave been impregnat ed with
a two products flame retardant: Commercial Retardant, which is formed by a combination of a resin polymeric and acid phosphoric
and Borax (Na2B4O5(OH)4•8H2O) with Sodium Hexametaphosphate (Na16P14O43). These Retardants has the advantage of the fact
that it can be applied to the substrates mixed with water in the relation 1:1, 1:2 or pure. In order to reduce the flammability, Textile
fabrics are coated with flame retardants. The flame retardant capabilities, mechanical properties and structural characteristics of the
textile fabri cs before and after th e use of these prod ucts were investigated throughout the special t extile meth ods for inflammability
and mechan ical resistibil ity. Aft er the use o f the fla me retardants t he mechanical p roperties o f the fabrics were impro ved or at least
remained the same as compared to fabrics without any treatment. The use of Borax / Sodium Hexametaphosphate /Water results in
the essential increase of co mbustio n retardation time about 2 minutes as compared with 8 seconds for untreated fabrics.
Keywords: Acrylic; Borax; Flame Retardant s ; Sodium Hexametametaphosphate; Textile Fabrics
1. Introduction
Flame retardants in their various forms have been used in passive
protection of timber and other building materials, including
metal structures in many textiles and synthetic fibers, as well in
a wide variety of technical applications of plastics, mainly in
the electronics industry [1,2]. Flame retardants can be incorpo-
rated into a material either as active or as additives ones. The
active components are incorporated into the polymeric str uct ure
of some types of plastics. This method is preferred because it
produces more stable and uniform properties. Additives are also
cheaper and versatile. However, they have the disadvantage to
modify the properties of base materials. This is the case of the
polybrominated flame retardants, which usually of view are
applied as coatings or mix during the pro cessing of materials
such as plasti cs and fibers [3,4].
From a technical standpoint, the effectiveness of fireproof
coating is based on two fundamental aspects in depending on
type of fibers. In natural fibers, as cotton and wool, it is impor-
tant to maintain their properties such as of touch, comfort, etc.,
which do not have other heat-resistant fibers, the durability of
retardan t ef fect again st washi ng, th e use an d a competi ti ve cost.
In synthetic fibers, the possibility of fireproof material limits
the importance of the application in the dyeing, which only has
the effectiveness in blends with natural fibers, because of the
strength of the effect brought by the incorporation of the addi-
tive mass versus fixation by impregnation [5,6].
Regarding fireproof coating for synthetic fibers, the main interest
is treatment of polyester fibers not only due to their commercial
importance, either alone or in blend with other fibers, but also
because of the obtained success with this fiber at flame retar-
dant treatment as compared with other synthetic fibers [7].
Extreme flammability of the acrylic fibers is caused by stron g
exother mic rea ction of pyrol ysis that takes p lace at temperature
of 300ºC fo r most commercial varian ts. This reactio n gives rise
to the formation of flammable nitriles and monoxide carbon. In
order to control this reaction it is possible to add a flame retar-
dant to the fiber for appreciably promotion the carbonization
[8,9]. The replacement o f acrylic fibers b y firepro of modacr ylic
ones is often useful, but this replacement has the disadvantage
because of a very high cost of these fibers. This is the reason
why there is interest of application of fireproof coating for this
type of fibers to retard of flame a nd at the same time th is coat-
ing must not affect the mechanical properties of fabrics im-
pregnat ed.
2. Exp erimenta l Pro cedu r e
Two flame retardant products based on Borax and Sodium
Hexametaphosphate was used in order to coat textile fabrics
with the composition 100% acrylic. Also the textile fabrics
were coated with a commerci al fl ame retardan t fo r compariso n.
The process of coating was carried out by the immersion me-
thod, which consists of completely submerge of the fabric in a
bath containing the aqueous solutions of flame retardant prod-
ucts. After the coatings of the fabrics were characterized with
microscopy (SEM) JEOL-6300 in order to analyze the ef fect of
the flame retardant products on the fabric. The flammability
tests for the samples with or without flame retardant products
were carried out in order to observe their behavior under fire.
Copyright © 2012 SciRes. AMPC
The tension test too was made to the samples to observe the
effect of the coatings on the mechanical properties. For tensile
test were used the NMX-A-059-INNTEX, whereas for ripped
test a NMX-A-109-INNTEX and for inflammability test the
3. Results and Discussion
3.1. Mechanical Properties
3.1.1. Tens ion Results
After the use of the flame retardants the mechanical properties
of the fabrics were improved or at least remained the same as
compared with the fabrics without any treatment, because the
retardants form a coated on the textiles, the better results for the
tension test are those for the mix Borax/Hexametap hosphate o f
Sodium/Water in the warp and weft.
The results of tension test in original samples and after the
treat ment with different retar dants ar e s ummarized in Table 1.
3.1.2. Ripped test
Only in two values the resistance to rip is equal to the original
of the acrylic warp with the commercial retardant and with the
mix of Borax/Hexametaphosphate of Sodium/Water as seen in
Table 2 . It is agreement with the values of elongation. The lost
of elongation made the acrylic more stiffness and the sample
lost resistance to rip.
3.1.3. Inflammability
The flame retard ant cap abil ities of the textil e fabrics befo re and
after the use of the flame retardant products were investigated
using the special textile methods for inflammability. The results
of the inflammability tests after the use of different products are
presented in Table 3.
From this table one can observe that the burning time of the
fabrics treated with the solution based on Borax (Na2B4O5
OH)4•8H2O) in creased in several t imes i n d ependence on Borax
concentration. The treatment with the solution Borax/H e xame-
phosphate of Sodium (Na16P14O43) lead s to the same resul ts. So,
Table 1 Results of the Tension Test (Kgf).
Water 1:1
Borax/Hex am e
taphosphate of
Table 2 Results of the Ripped Test (Kgf)
Water 1:1
Borax/Hex am e
taphosphate of
Table 3 Results of the In f lammability Resistance Tests (S ec.)
of Sodium
Figure 1. SEM micrograph of the sample coated with Borax 100g/l
/Hexametaphosphate of Sodium to 100g/l (1000X).
these flame retardant products can stop the combustion of fa-
brics on certai n di stan ce befo re the sa mple with t he co mmercial
retardant product will be completely consumed. The possible
explanation of such result is due to decomposition of Borax and
liberation of water, which retards the fire propagation in the
sample. This process takes place because of low melting point
(75ºC) of Borax. For the fabrics after treatment with solution
contained Borax and Hexametaphosphate of Sodium the same
result s were o btained. If Borax forms water at the moment of its
decomposition then the Hexametaphosphate of Sodium, which
is the compound contained phosphorus and oxygen, at the de-
composition gives rise phosphoric acid (H3PO4), which reacts
with the hydroxyl groups released by the Borax producing of
dehydration. The dehydrated materials, which were formed
from the Borax, generated remaining carbon relatively fire-
esistant, which functioned like a barrier and inhibited the de-
gradation and protected th e material from the pyrol isis.
3.1.4. Scanning Electron Micros copy
SEM was used in order to observe how the flame retardants
have been deposited onto coated fibers Figure 1 it can b e seen
the formation of small crystallites on the fiber surface after
immersing in the solution with Borax. From this image it can
be con cluded that th e covering process es of the acrylic fiber by
two different retardan t materi als are dif ferent. At the sa me time
Borax, also does not interact with the fiber chemical structure,
however instead of the film formation crystallites grew on the
fiber sur fa ce.
4. Conclusions
The flammability tests the fabrics with the prep ared new flame
retardant products showed very good results such as 8 seconds
of combustion for the untreated fabric and 2 minutes for the
fabric treated with the solution of Borax / Hexametaphosphate
from Sodium /Water. This result shows the essential in crease o f
combustion retardation time. The gained time space is very
important as during these 2 minutes at a conflagration it is
possible to save lives or to control the fire. The tension Test
Resistance is better with the mix of Borax and Hexametaphos-
phate than the original Acrylic.
The scanning electron microscopy shows that the flame
commercial r etardant is depo s ited on the su r face o f the fab r ic as
Copyright © 2012 SciRes. AMPC
a thin film and the solutions based on Borax and Hexameta-
phosphate of Sodium were deposited in the form of crystals on
surface. These coatings do not produce any new chemical spe-
cies within the internal structure of the fiber.
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