Mechanical Properties of Unsaturated Polyester Filled With Silica Fume, Glass Powder and Carbon Black

-In this study a polymer matrix composites (PMCs) have been prepared with the aid of ultrasonic wave dispersion method for mixing , using of unsaturated polyester resin with Silica Fume(SF), Glass Powder (GP)and Carbon Black (CB). Moulds were prepared by hand-made from silicon rubber according to the ASTM standard table (4). The fillers added separately with different ratios as (0%,0.5%, 1%, 1.5 %, 2%,2.5% and 3%).The results show increase the hardness and impact strength when added GP, SF, and CB to polymer matrix. Flexural strength and maximum shear stress decrease when added silica fume , but when added glass powder and carbon black led to increase flexural strength and maximum shear stress to certain percent at ( 2%, 1.5% for GP and CB respectively) then dropped when increase weight fraction of GP, CB . Compressive strength decrease when added glass powder and carbon black, while it is increase when added silica fume to polymer matrix. Wear rate decrease when increase weight fraction of carbon black but it increases when added GP and SF.


Introduction
Composites are characterized as materials which incorporate at least two or more physical and chemical various phases, the distinct interface separated between them. The various systems combine with each other to form a system possesses the properties of structural and functional more than constituent alone. Composites, are wonderful materials have become a basic part of today's materials because of the advantages possessed by such as low weight, high fatigue strength, corrosion resistance, assembly faster, which is used widely as materials in the manufacture of the shuttle space structures, packaging to medical equipment and construction [1]. Flores et al. studied the influence of filler structure onto micro-hardness (H) for low density Polyethylene-carbon black and polycarbonate -carbon black composites. They were used two kind from microadditives at various average particles sizes. It was found that the morphology of the polymer matrix affect on the hardness of composites which depend on the composites and the volume concentration for filler. The micro-hardness for polycarbonatecarbon black composites shown a step like behavior regarding to content of carbon black, whilst the H values for low density polyethylenecarbon black composite linear increasing with increase volume concentricity for filler. Their Results shown the smaller particle size of carbon black enhances the micro hardness of the composites [2]. Hassan et al. developed polyester/eggshell particulate composites, he was utilized carbonized and uncarbonized eggshell particles as reinforcing into polyester matrix. Eggshell particles at (10%, 20%, 30%, 40% and 50%) of weight were add to polyester as reinforcing materail. The microstructural analysis for the particulate composites (polyester/eggshell) was carried out utilization a scanning Electron Microscopy (SEM)) and Energy Dispersive Spectroscopy (EDS). Results shown the hardness and density for the particulate composite increased with increasing the addition of eggshell. The bending strength and tensile for the composite increased with increasing for weight of eggshell particles into polyester matrix, from the SEM detected better strengthening effect of carbonized eggshell due to better interfacial bond between polyester matrix and carbonized particles [3]. Alkhafaji studied the mechanical and electrical behavior for composites from polymer matrix and their hybrids, particles of carbon black used as reinforcing material at constant volume fraction (10) % and boron particles at various volume fractions (0%, 2%, 4%, 6%) which are bounded with unsaturated polyester resin. Results showed increasing in hardness values with volume fractions of boron powder. It is observed the values of hardness are increased with increasing volume fraction of reinforced boron 146 particles to matrix due to the boron particles have excellent hardness compared with black carbon particles, in hybrid composite material: polyester resin reinforced with hybrid particles of (black carbon-boron), the hardness increase with contain of boron [4]. Saleh et al. studied mechanical properties of epoxy filled with fly ash and silica fume added each filler separately with various ratios as (10%, 20%, 30%, 40%, 50%), their results showed that the increase of additives ratios of silica fume and fly ash caused increasing the compression strength and tensile strength, the increase of additives ratio of silica fume causes decreasing in bending strength [5]. Musa studied the influence of adding glass powder of grain size (35μm) with various volume fraction (10%, 20%) to the blend of unsaturated polyester and polyurethane. Her results have shown that the addition of particles to the polymer blends lead largely in mechanical properties it has shown that the values of young modulus, impact strength and hardness (shore D) were increase with increasing of volume fraction of glass powder. Fracture surface of the samples were examined using optical microscope with magnification (40 X) and the results showed that the nature of fracture is seems brittle fracture for all samples [6]. This work aimed to evaluate the mechanical properties (hardness, bending, impact strength, compression strength, and wear) for unsaturated polyester as a matrix with silica fume, glass powder and carbon black as reinforcement composite systems.  is a by-product of melting process in ferrosilicon and silicon industry. The decrease for high pureness quartz to silicon at temperature up to 2000 C° output SiO 2 vapour, that oxidizes and condense at lower temperature zone to teeny particles consist of noncrystalline silica. Table 2 shows the typical characteristics of silica that used in this research. b. Carbon Black Carbon black is a material produced by an insufficient combustion from heavy products of petroleum. Carbon black is a take shape of amorphous carbon that has a high surface to area ratio. Traditionally, carbon black is utilized as a reinforcement agent in tires. Today, due to the unique properties owned by carbon black, has expanding its uses to include pigment, stabilizing ultraviolet light (UV), and conductive agent in a variety of every day and specialty products of high performance which include: tires, products of industrial rubber, electrical discharge compounds, high performance coating, ink and toners printing [7].

Nomenclature
c. Glass Powder Glass is a solid material generally composed of noncrystalline silica, calcium oxide, sodium oxide and another components. The chemical composition rely on the raw materials utilized and vary slightly from each kind of glass. Glasses generally refer to hard, brittle, transparent material; have low ductility, low thermal expansion and low thermal conductivity so it has low resistance to thermal shock. Glasses have a resistant to many solvents, acids and other chemicals [6]. Glass powder used in this research was prepared from the cups transparent glass; it was crushed to small pieces and then milled to micro-scale (75μm).

Preparation Technique I. Mould Preparation
The moulds of specimens used in the compression, bending, and hardness, impact and wear test are fabricated from silicone rubber, The shape and dimension of all moulds are fabricated according to the standard dimensions (ASTM) for each test. Samples dimensions shown in Table 4.

II. Preparation of polymer matrix composites
Polymer matrix composites (PMCs) were prepared from additives (silica fume, glass powder and carbon black) filled unsaturated polyester matrix at different weight fraction (0, 0.5, 1, 1.5, 2, 2.5, 3) %. In the present work, the ultrasound technique is used for manufacturing of PMCs due to its efficiency in breaking the agglomerating of microparticles and making them homogeneously dispersed in the polymer matrix, as well as, to ease of cleaning tools. .

II. Hardness test
This test was carried out utilize a Digital Micro Shore D (Durometer) (QUALITEST HPE) device according to (ASTM D2240), it is manufactured in USA. Seven measurements of hardness were made at different positions on the specimens to determine the average value.

III. Bending Test
This test is called three points test, the bending tests were performed according to ASTM-D790 standard with dimensions of sample: length (100mm), width: (10 mm) and height: (5mm).
The test was carried out using the universal mechanical test machine (Model RH1 5DZ, Tiniusoisen Ltd), it was made in England.
The main purpose of this test is to calculate the maximum flexural strength and maximum shear stress by equations (2) and (3) respectively:

IV. Compression Test
Specimens were presented according to standard (ASTM D 695) at room temperature with a speed rate of (1mm/min), as shown in

Results and Discussions
I. Impact strength Figure 7 indicating the relation between the impact strength and the weight fraction for GP, SF, and CB that are added to the UP matrix.
Results have detected that the maximum amount of impact strength (4.357kJ/m 2 at 3%), (4.01762.598 kJ/m 2 at 3%) and (4.181kJ/m 2 at 2.5%) for GP, CB and SF respectively, compared to the impact strength of the neat (2.598kJ/m 2 ).The increase in the concentration of the filler increase the ability of matrix to soak up energy and that way increases the toughness, so that impact strength is increases. It is observed that the filler with smaller particle size show a higher increase of impact strength. The dropping in the impact strength value may be attributed to low the adhesion between the particulate filler with the matrix or the presence the tiny voids within the sample, which led to a decline in values of impact strength.

II. Hardness Test
Hardness is a measure of the resistance to penetrate the surface, as they are a function of stress required to produce some certain types of deformation of the surface [8]. Figure 8 indicating the relation between the hardness shore D and a weight fraction for GP, SF and CB tha are added to UP matrix. Results show a higher value for hardness shore D is (87.93 at 3%), (84.16at 0.5%) and (84.21at 3%) for GP, SF, CB respectively, compared to the hardness shore D of the neat (65). The increase in hardness values with increase weight fraction of glass powder and carbon black agree with results of Musa [6] and Flores [9]. Hardness values increased for all samples which strengthen by glass powder, silica fume, carbon black due to increased crosslinking and stacking of the unsaturated polyester matrix (which reduces the. movement. of polymer molecules), which led to increased resistance to scratching material and cutting, thus increase hardness values.

III. Bending test
Bending describe the behavior of a structural element subjected to an outer force applied vertical to the axis of the element [10]. Figure 9 shows the relation between the bending (flexural) strength and the weight fraction of GP, SF and CB that were added to UP resin. From results show decrease in flexural strength when adding SF as filler, while flexural strength increase to (665.61Mpa at 2%) and (383.9Mpa at 1.5%) when added GP, CB respectively, and then dropped when increase in weight fraction of GP, CB. The increase in flexural strength may be attributed to a small amount of particles dispersed homogenously in unsaturated polyester, that leads to a strong interface between particles surface and unsaturated polyester because of its own higher surface area, and thus got improved in the flexural strength. Figure 10 shows the relation between the shear stress and weight fraction of the GP, SF and CB, from the Figure 10 showed particle-reinforced composites, most of these composite materials, the particulate phase is harder and stiffer compared to the matrix. These reinforcement particles tend to restrict the movement of the matrix phase in the closeness of each particle. The principle of the matrix transfers some of the applied stress to the particle. The degree of reinforcement or improvement of mechanical behavior depends on strong bonding at the matrix -particle interface [11].

IV. Compression Test
This test includes an axial compression force applied on the compression standard specimen with a square cross-section. Figure 11 shows the effect of GP, SF, and CB at various loading level on compressive stress of unsaturated polyester matrix. Properties of wear can be changed substantially by the change in the microstructure, mechanical properties of the reinforcing phase, the weight fraction, and the nature of the interface between reinforcement and matrix [9].