Studying The Effect of Some Inorganic Phosphors Salts on Fire Retardant And Mechanical Properties of Unsaturated Polyester Composite

In this work, the effect of four types of inorganic phosphors salts on flammability and mechanical properties (Flexural and Tensile) strength, of unsaturated polyester reinforced with glass fibers has been studied ; also , the influence of two types form of glass fibers (chopped strand mat and woven roving ), on flammability and mechanical properties of the composite, were studied . Sheets of composites with different weight percentage of additives and reinforced with two layers of each type of glass fibers, were prepared. Four standard test methods used to measure the flame retardation and mechanical properties, which are: ASTM: D – 2863, ASTM: D – 635, ASTM: D – 790 and ASTM: D – 638. Results obtained from these tests indicated that, additive IV has high efficiency as a flame retardant, self – extinguishing (S.E.) was occur at the percentage 1.5 % and non – burning ( N.B. ) was occur at the percentage 2.5 % for resin reinforced with glass fiber type woven roving and showed high effect to reduce the values of the mechanical behaviors, but additive I have low effect on retard composition and showed low effect on the values of mechanical properties.


Introduction
Polymers, also called macromolecules are giant molecules in which atoms are linked together by covalent bonds along molecules [1] .The polymers were prepared by process called polymerization where monomers (structural units) react together chemically to form linear or branched chains or three dimensional polymer network [2] .In the cross linked polymers, the chains are joined chemically at fastening points.The degree of cross-linking has effect on the physical and chemical properties of polymer [3] .
Composite is generally defined as any physical combination of two or more dissimilar materials used to produce a result that cannot be obtained by each component individually [4] Properties of composites are strongly influenced by the properties of their constituent materials, their distribution and the interaction between them.Besides specifying the constituent materials and their properties, a composite material as a system is described by the geometry of reinforcement [5] .The geometry of reinforcement may be described by some important factors [6] : shape, size and size distribution of reinforcing materials ; concentration distribution and orientation of reinforcing material.
Most composite materials developed thus for have been fabricated to improve mechanical properties [7] .The interaction between the matrix and rcfibers are effective in improving the fracture resistance of the matrix.The fibers have small cross sectional dimensions so that they are embedded in matrix materials to form fibrous composites [8] .Most of reinforced plastics are glass fiber reinforced polyesters .They are used in many important applications [9,10] , so that , in this work the influence of increasing the ratio of additives as flame-resistance on mechanical properties of reinforced polyester composite were studied .measuring flammability of polymers [11] .b-ASTM: D-635 : The measurement of rate of burning (R.B), average extent of burning (A.E.B) , average time of burning ( A.T.B ) , self -extinguishing ( S.E ) and nonburning ( N.B. ) [12] .c-ASTM : D-790 : The measurement of flexural strength, by three point method [13] , with constant rate of displacement (crosshead speed) equal to 1 mm/Min., by using Instron-1122 instrument.d-ASTM: D-638 : The measurement of tensile strength [14] , with constant rate of displacement (crosshead speed) equal to 1 mm/Min., by using Instron -1122 instrument .

Preparing of specimens
The specimens of polymeric material containing additives and reinforced with two layers from two types of glass fibers were prepared in dimensions (150 x 150 x 5) mm, two sheets were prepared for each percentage, weight (0.5, 1.0, 1.5, 2.0 & 2.5) % of flame retardant materials with each type of glass fibers.These sheets cut as a samples according to ASTM standard were used in this work .

Results and discussion A/ Flammability Tests:
The results of the flammability tests for unsaturated polyester resin reinforced with glass fibers in the form of chopped strand mat and in the form of woven roving, were showed in Tables 1 -4 , for limiting oxygen index and rate of burning respectively .The limiting oxygen index (LOI), were increased with increasing the weight percentage of additives, as shown in Tables 1 & 2 respectively, and illustrated in Figures 1 & 2 for tow types form of glass fibers respectively.
The rate of burning (R.B) of the resin reinforced with glass fibers in two types form with the additives has a continuous reduction with increasing the percentage weight of additives (inversely proportional), as in tables 3 & 4 respectively.Figures 3  & 4 showed the flame speed curves of flame retardation for resin in two types form .This results indicated that, the additive IV has high efficiency on self-extinguishing (S.E) of resin, especially in percentage 2.0 % for the resin reinforced with glass fiber type chopped strand mat and in percentage 1.5 % for resin reinforced with glass fiber type woven roving.Non-burning (N.B) occur in percentage 2.5 % for the resin reinforced with glass fiber type woven roving .In general , additive IV has the best efficiency on retard combustion.This high efficiency depends in basically on the structure of this material (Polyammoniumphosphate), its contain in their structure on phosphour element and nitrogen which have high effect on retard combustion.The free radicals were form from decomposition of this materials (P .and N .) will reacted rapidly with the free radicals of flame chain, such as (H flammable.The char will form as results from the thermal decomposition of the specimen; it covered the polymer specimen's roof .
The difference in the results of the flammability tests between the polyester reinforced with chopped strand mat and that reinforced with woven roving, results from the difference in the form and size distribution of glass fibers.The layers of glass fibers in the resin reinforced with the woven roving of glass fiber would move away from one another during the burning of the composite due to the presence of the resinrich layers between the plies, this movement led to facility in the flame spread, while that did not occur in the case of the resin reinforced with the chopped strand mat of glass fiber.

B/ Mechanical Properties Tests
The mechanical properties of polymers depend on many factors like: molecular structure, types of branching, space distribution between main chains which contains molecular groups and the percentage of cross linking density between these back-bones chains [15][16][17] .
In this work, the mechanical properties of composites depend on two factors; the types form of glass fibers and the structure of additives.The woven roving form of glass fibers caused increase in the mechanical behavior comparing with the chopped strand mat form, because regularly distribution of fibers in woven roving form, caused high density cross linking of this composite .The results of the mechanical tests for the resin reinforced with two types form of glass fibers and containing different percentage of additives, shown that the mentioned additives would led to lower values, as illustrated in Figures 5 & 6 .This reduction in the mechanical behaviors is attributed to influence of these additives on matrix, because the hard particles placed in brittle material lead to stress concentration in adjacent matrix and the presence of these additives between polymer chains obstructs local mobility of chains and thus, the polymer will show little strain, and their effect on the interface where they reduce the adhesion (interfacial bonding) between the fibers and matrix .
Also, results of tests appeared that the additives caused decrease in mechanical strength and modulus for composites with increasing of the percentage of additives, as shown in Tables 5 & 6 for both tests (flexural and tensile) respectively.

Conclusions
The main conclusions of this work can be summarized as follows: 1-The efficiency of the flame retardation for additives were in the following order: IV > III > II > I 2-Limiting oxygen index (LOI) was increased with increasing of weight percentage of additives, but the rate of burning (R.B) was decreased with increasing of weight percentage of additives.3-Additive IV has high effect on retard combustion for two type of composite, but it reduces the mechanical properties.4-Additive I showed low effect on retard combustion for two types of composite, and it showed little effect on the values of mechanical properties comparing with additive IV.
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& Tech. Journal, Vol.28, No.17, 2010 Studying the Effect of Some Inorganic Phosphors Salts on Fire Retardant and Mechanical Properties of Unsaturated
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Table ( 2) Limiting Oxygen Index (LOI) of unsaturated polyester resin reinforced with glass fiber type woven roving, with additives
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Journal, Vol.28, No.17, 2010 Studying the Effect of Some Inorganic Phosphors Salts on Fire Retardant and Mechanical Properties of Unsaturated Polyester Composite 5554 Table (4) Rate of burning (R.B) of unsaturated polyester resin reinforced with glass fiber type (woven roving) with additives
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Journal, Vol.28, No.17, 2010 Studying the Effect of Some Inorganic Phosphors Salts on Fire Retardant and Mechanical Properties of Unsaturated Polyester Composite 5555 Table (5) Flexural Strength (S F ) and Flexural Modulus (E F ) of unsaturated polyester resin reinforced with glass fiber (in two forms) with additives
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Tech. Journal, Vol.28, No.17, 2010 Studying the Effect of Some Inorganic Phosphors Salts on Fire Retardant and Mechanical Properties of Unsaturated Polyester Composite 5556 Table (6) Tensile Strength (σ T ) and Young Modulus (Е) of unsaturated polyester resin reinforced with glass fiber (in two forms) with additives
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