Study the mechanical properties of epoxy resin reinforcement by ziziphus spina-christi powder

Ziziphus Spina-Christi bark and other natural debris may be found in abundance in the nearby area. The mechanical qualities of all of these waste natural resources are outstanding, and they may be utilized more professionally to create composite materials for a variety of applications. Epoxy resin modified with organic natural particles such as Ziziphus Spina-Christi bark powder has been used as reinforcements in polymer matrixes instead of non-degradable synthetic reinforcement such as glass, carbon, or aramid. The tensile, impact and flexural characteristics of the Ziziphus Spina-Christi bark particles enhanced epoxy resin are examined in this publication. This paper studies the effects of weight fraction (3, 5, 7 & 9%) on the characterization of composite materials. The results show that the mechanical characterization of epoxy improved when added 7% from the particles of Christi. Where the hardness increased up to 77 (Mpa). Also, the impact strength reached 8.7 (KJ/m 2 ) with a 7 wt% filler added, and the tensile strength increased from 18 (MPa) to 45 (MPa). The flexural strength of pure epoxy is 160 (MPa), and it increases linearly with the addition of Ziziphus Spina-Christi bark to 173 (MPa).


Introduction
Epoxy resins may be made to display outstanding chemical resistance, high thermal & electrical resistance, tremendous adhesion, little shrinkage, and useful mechanical features, such as great toughness and strength, in addition to superior mechanical properties. Manufacturing, packaging, aerospace, and building all benefit from epoxy resins. As a result, they are used in a broad range of applications from bonding & adhesive applications to electrical laminates to garment finishes to fiber-reinforced plastics to flooring and pavements [1]. Zizyphus Lotus bark (Z. Lotus), sometimes called jujube, is an angiosperm member of the Rhamnaceae family. This family contains around 135-170 Zizyphus species [2]. Z. Soil conditions in China, Africa, Iran, Europe, and South Korea, particularly Cyprus, Greece, Sicily, and Spain, are ideal for growing the lotus [3][4]. tea, Honey, jam, oil, juice, bread, and cake are just some of the ways this plant is used in nutrition, health, and beauty. Traditional medicine in the Middle East and North Africa uses a few sections of Z. lotus to treat a wide range of ailments, including urinary tract infections, diabetes, fungal infections, skin infections, insomnia, bronchitis, and low blood sugar [5][6]. In contrast, the jujube, a delicious red fruit, was consumed by indigenous peoples in huge numbers fresh, dried, and processed as a food source. [7].

Epoxy Resin
The hardener used was Poly inject EP 10. It is liquid and added to the resin in a weight ratio of 1:3 (hardener: resin), and thus the chemical bonding and crosslinking were formed within the epoxy resin. produced by (Al-Rakaez Building Materials in Amman) and made in (Egypt Arabic). Typical properties of a resin used in the current experimental work are listed in Table 1.

Zizyphus lotus bark
The root barks of Zizyphus lotus were extracted with water, chloroform, ethyl acetate, and methanol to determine their anti-inflammatory and analgesic activities. Aqueous extract (50, 100, and 200 mg/kg) given intraperitoneally (i.p.) showed a significant and dose-dependent antiinflammatory and analgesic activity. Chemical analysis of Ziziphus lotus bark after (X-ray Fluorescence) using reagents Compton secondary molybdenum and Barkla scatters HOPG. Showing in Table 2. The test was completed at the University of Technology, Baghdad, Iraq .

Preparation of composites
All specimens were composited using a rubber mold. A layer of wax was applied to the mold to allow for easy removal of the specimen.

Tensile test
This test is performed according to (ASTM D638) in room temperature. Fig.1.shows specimens for tensile test stander matching with ASTM D638-03 [13]., Figure (3) shows the tensile strength machine used in this research, the test was completed in the material engineering department/ University of Technology/ Baghdad/Iraq.

Flexural test
The flexural test can also be called as bend test, Samples have been cut into the dimensions (125*12.7*3.2) mm according to ASTM D 790-86 [14].    [15]. Impact resistance is calculated for samples from the following relationship [16]. This test is performed according to (ISO-180) at room temperature. Samples have been cut into the dimensions (80*10*5) mm. the inspection was done in the material engineering department/ University of Technology/ Baghdad/Iraq.

Hardness shore (D)
The ASTM of hardness shore D test is conducted related on (D-2240) at room temperature(Annual Book of ASTM Standard, 1988). samples cut off into a diameter of 40mm and a thickness of 5 mm. device founded in the polymer laboratory at the Materials Engineering Department, University of Technology. Per each sample, five hardness tests were taken, and the average hardness was fixed. Ziziphus Spina-Christi bark) concentrations, which is likely due to the fact that tensile properties can be influenced by a variety of factors, including filler content rather than the particle-matrix interface, homogeneous particle distribution within the resin, & the stiffness of the reinforcing particles; all of these factors contributed to the enhancement of tensile properties [17 & 18]. There may have been a lack of bonding between resin and filler, which caused microcracks to form at the interfaces of the sample composites when 9 percent weight fraction Ziziphus Spina-Christi bark powder was used in epoxy resin [19].  [20]. It was discovered that the addition of 9 percent weight fraction Ziziphus Spina-Christi bark powder to epoxy resin resulted in a drop in modulus of elasticity from 11.1 to 9.2 GPa. That's because reducing deformation by rising the surface contact area between the matrix & reinforcement [21]

Flexural Test
EPO/Ziziphus Spina-Christi bark composites with various filler weight percentages are shown in fig.9. Flexural strength of the pure epoxy was 160 MPa, which grew linearly with the addition of Ziziphus Spina-Christi bark up to 169 percent, or 7 wt. percent, but decreased to 165 with the addition of 9 percent). Unofficially, the inclusion of Ziziphus Spina-Christi (7 percent weight) increases the adhesive properties of the composite with increasing mechanical joining among epoxy and filler, which rallies stress transfer after application of loads [18]. When 9 percent weight Ziziphus Spina-Christi filler was added, flexural strength was reduced because the structure's integrity deteriorated due to the agglomeration and gaps. The losses in flexural strength were attributed in part to the existence of Ziziphus Spina-Christi in the matrix, which is in line with [22]. device established at Materials Engineering Department, University of Technology. by using the machine type Laryee, Chinese made (Model 1031).

Figure 9. Flexural strength of the specimen
The fig.10. the flexural modulus of epoxy / Ziziphus Spina-Christi bark at various filler weight fractions 7. The pure epoxy has a flexural modulus of 2 GPa & is linearly increased by 7.8 GPa percent up to 7wt. percent Ziziphus Spina-Christi bark, but is decreased to 6.2 GPa when 9 percent Ziziphus Spina-Christi bark is added, as shown in figure (8). The stiffness of the epoxy in combination with its content may contribute to the composites' increased flexural modulus. The filler may restrict the polymer chain's free flow, hence limiting the polymer's capacity to deform. This might be attributed to the improved interfacial bonding between the filler & matrix, wherever stiffness is determined by the filler quantity, filler type, & filler dispersion similarity. These parameters, which determined the proper filler dispersion in the composite structure, may be checked by watching the composite's linear modulus increase [23]. By adding 9Percentage weight to the Ziziphus Spina-Christi bark, the flexural modulus qualities are limited. This is due to material aggregation & a lack of homogeneity between the filler & the cause polymer, which degrades the stiffness of the samples [24]. Figure 11. illustrates the hardness shore D values for the epoxy reinforced Ziziphus Spina-Christi bark The findings may indicate an increase in hardness with the addition of Ziziphus Spina-Christi bark, with 77 hardness shore D with 7 wt percent Ziziphus Spina-Christi bark. Increased Ziziphus Spina-Christi bark content owing to an increase in hardness. This might be because hardness is often thought to be a surface attribute, or because Ziziphus Spina-Christi bark includes materials that are harder than pure epoxy, resulting in a rise in hardness. The rationale for enhancing the hardness of composite materials is that the addition of filler results in a rise in resistance to plastic deformation; this outcome is consistent with [25].

Impact test
The impact strength results for the epoxy/Ziziphus Spina-Christi bark samples are shown in Fig. 12 of the filler matrix (epoxy) and was caused by the reduction of void spaces in polymeric composites. This may be because filler particles absorb more stress energy as their concentration in the matrix resin rises [26]. Additionally, this chart demonstrates that the impact strength is reduced with the addition of (9 percent by weight) Ziziphus Spina-Christi bark, indicating that the matrix resin is likely insufficient to effectively transmit the stress generated by a sudden impact when combined with the filler's low absorption capacity. A high filler content has been demonstrated to improve the possibility of fiber aggregation, resulting in regions of high stress that need less energy to propagate [27,28].  The impact strength drops with the addition of Ziziphus Spina-Christi bark (9 percent weight) to 7.5 KJ/m2 Ziziphus Spina-Christi bark owing to the matrix resin's inability to efficiently transmit the stress generated by a quick impact combined with the filler's poor water absorption characteristic. In certain circumstances, it has been shown that a great filler content enhances the possibility of fiber aggregation, resulting in areas of high stress that need less energy to propagate.