Analysing Some Mechanical Properties of Cinnamon Powder Reinforced with Polymeric Materials Used in Dental Application

In the dentures industry, materials must be chosen to have good mechanical properties in order to resist the conditions that may occur in the mouth. A study was conducted to assess tensile strength, elasticity coefficient, elongation, flexural strength, flexural modulus with impact properties of poly methyl methacrylate resin as matrix strengthened with cinnamon powder and also analysing these mechanical properties by using (OriginLab) software program. The samples of Poly Methyl methacrylate bio composites which containing 2%, 4%, 6%, and 8% weight fractions of cinnamon powder and an unfilled as control sample were fabricated using “hand lay up” method. The results indicate that the addition of 8% weight fraction cinnamon powder into Poly Methyl methacrylate resin improved of ultimate tensile strength, modulus elasticity ,flexural strength, flexural modulus (62 MPa, 3.7 GPa, 96 MPa, 6.4 GPa) respectively, compared with the values of pure Poly Methyl methacrylate (51 MPa, 1.5 GPa, 78MPa, 2.0 GPa) respectively. Also can be noted that the elongation at break values decreases with an increase in weight fractions of filler, where the sample (Poly Methyl methacrylate +2% cinnamon) has the best value for elongation compared with samples reinforced (4%, 6% and 8% wt). The impact strength results observe the maximum value was present in the sample (Poly Methyl methacrylate+6% cinnamon). From the results, descriptive, One Way ANOVA statistical analysis and means comparison by used (Scheffe test and Tukey test) for all mechanical properties indicated, turns out if Sig equals 1 shows that the variance in mean is significant at the level of 0.05, whereas Sig is 0 designates that the mean variance is not significant at the level 0.05. KeywordsPoly methyl methacrylate, Cinnamon powder, tensile properties, Flexural strength, Flexural modulus, Impact strength, Origin Lab. How to cite this article: A.M. Al-Ghabban., R.A. Mohammed and J.R. Mahmood, “Analysing Some Mechanical Properties of Cinnamon Powder Reinforced with Polymeric Materials Used in Dental Application,” Engineering and Technology Journal, Vol. 37, Part A, No. 3, pp. 96-105, 2019.


1.Introduction
Composites are substances that do not resolve in any other and produce new material of unique advantages. Reinforcement materials in the form (particles or fiber or both together) usually are added to the based material to improve the mechanical properties, reduced shrinkage characteristic and improve bonding nature between the base material and the reinforcing material [1][2]. Composite materials which usually consist of a one or two materials' natural, non-toxic such as (jute fiber, eggshell, banana fiber, cinnamon, Clove, Pomegranate, Walnut.... etc.) are called bio-composite materials. Biocomposites materials are used in many applications, for example (teeth, prostheses, orthodontics, hip joints etc.…). The bio-polymer resin composite materials are mostly used for immediate renovation, both posterior and anterior teeth, due to good mechanical and physical characteristic of these materials [3]. Poly Methyl methacrylate, a polymer used in the manufacture of a denture, an alternative to lose teeth and peripheral tissues, this material should be has good mechanical properties (impact strength, flexural strength and wear resistance.... etc.) and is compatible with the mouth environment, non-toxic and low water absorption [4][5]. Although Poly Methyl methacrylate materials it is widely used, but there are many drawbacks must be taken into consideration, so many researchers studied the effect of additives to improve mechanical and physical characteristic of Poly Methyl methacrylate material. Balos et al. [6] have studied effect of various additions Nano silica into Poly Methyl methacrylate resin matrix on modulus of elasticity and flexural strength. The samples are composed from Poly Methyl methacrylate resin reinforced with (0.05%, 0.1%, 0.2%, 0.5%, 1%, 2%) weight fraction Nano silica. Results observed the weight fraction (0.05% into Poly Methyl methacrylate) give the highest values of modulus of elasticity and flexural strength. Jha et al. [7]  The objective of the current work is attempting to obtain the new bio-composites prepared from cinnamon powder into poly methyl methacrylate resin which is used in the denture application. Also study the effect of various additives cinnamon powder on tensile, flexural and impact test of the poly methyl methacrylate composite.

I. Poly Methyl methacrylate
Poly Methyl methacrylate cold curing used a resin matrix kind from (Castavaria) equipped with a company "Vertex-Dental" to production the biocomposite samples used in denture base. Some mechanical and physical characteristic of Poly methyl methacrylate is indicated on the Table 1.

II. Cinnamon Natural Material
Cinnamon is a tree belonging to the Laureaceae family and crosses one of the most significant spices used in everyday life cinnamon originally contains vital oils and other derivative, example cinnamaldehyde, cinnamic acid, and cinnamate. The cinnamon can be used as an antioxidant, antimicrobial and antinflammatory [9]. Cinnamon has a beneficial effect on oral health and is utilized to treat oral infection, treat toothache with removing bad breath [10]. In this research was used cinnamon sticks after grinding for 3 hours by (Mill) to obtain cinnamon powder that used as a strengthened material at a different weight fraction (2%,4%,6%,8%) with Poly methyl methacrylate resin. The Figure 1 shows steps to prepare cinnamon powder. The particle size distribution was examined using (MASTERSIZER 2000) for cinnamon powder after grinding as illustrated in Figure 2, where the average particle size for cinnamon powder was (24µm). The chemical composition of the cinnamon powder was examined using X-ray Fluorescence spectrometer Technique, Table 2 shows the ratio oxides of the elements existent cinnamon powder, while Figure  3 (A-B) shows the ratio of elements existent cinnamon powder under the influence reagent compton secondary molybdenum , reagent Barkla scatter HOPG respectively.

Preparation Samples of Bio-Composites Materials
The dimensions of mould used in this research to prepare samples were (150 mm ×150 mm×5 mm).
The mold was made of glass and covered with a layer glass to achieve samples with fine surface and non-roughness. Poly methyl methacrylate denture base materials consist from monomer liquid and polymer powder. The mixing ratio of poly methyl methacrylate (cold cure) is usually about 17 gm powder and 9.5 gm liquid polymer. At the beginning, the specific ratio of polymer liquid is placed in a dry and clean glass flask and then adds the specified ratio of the dry powder gradually to the polymer liquid. The mixtures are mixed continuously and homogenously at room temperature and then pour the mixture into the middle of the mold. Leave the mixture inside the mold for 9-15 minutes at room temperature from beginning the mixing process to increase the viscosity of the mixture. Removing samples from the mold and put them in the oven at a temperature of 55 for 30 minutes [11] and cutting the samples according to ASTM of each test as shown Figure  4. Table 3 shows the composition details of biocomposite samples. A Tensile Test

Statistical Analysis
All statistical analysis was performed with (Origin Lab) program software using ((One-Way analysis)) of variance (ANOVA) with (Scheffe test and Tukey test) was utilized to analyze groups. The variations were always considered significant at (P-values) less than 0.05. Figure 8 shown the results of ultimate tensile strength performed on cinnamon powder based poly methyl methacrylate bio-composites. From the graph, there is clearly with the increased weight fraction of cinnamon powder leads to an increase tensile strength, where the sample (poly methyl methacrylate+ 8% cinnamon) has a high tensile value and improves the tensile strength property by 22% compared with pure sample. The reasons for increasing the tensile strength value; the first reason is that the elements and oxides found in cinnamon powder have increased the possibility of transfer the stress from poly methyl methacrylate polymer [20]. The second reason is that the average particle size of the cinnamon powder (6-200m) increases the covalent bond between the base poly methyl methacrylate resin polymer and the cinnamon powder material.    Figure 9 refers to the relation between modulus of elasticity and weight fraction of cinnamon powder into poly methyl methacrylate composite. It can be seen that the properties of the elasticity modulus improve with increase weight fraction of cinnamon powder into poly methyl methacrylate bio-composite. This advance in the properties modulus of elasticity depends on to the nature of cinnamon powder in terms of high strength. Thus modulus of elasticity values increased from (1.5GPa) for poly methyl methacrylate to (3.7GPa) for (Poly methyl methacrylate + 8% cinnamon). The elasticity modulus values improvement about (146%) compared with the pure sample this is due to the mean particle size, distributed regular of cinnamon powder inside the poly methyl methacrylate resin and easiness the penetration of polymer matrix material this leads to create good interfaces between the matrix material and reinforcing material [21].    Figure 10 illustrates the value elongation percentage of the samples poly methyl methacrylate reinforced with various weight fraction cinnamon powders. It can be observed that elongation percentage values decreased with increasing weight cinnamon powder, where an elongation value of pure sample poly methyl methacrylate (3.9%) decreased to (2.7%) with addition 8% cinnamon powder. The reason is that increase weight fraction of the reinforcement material will be the concentration of stress in polymeric composite materials and thus lead to a decrease in the value of elongation at break. In addition, the elongation properties depend on the natural behavior of the polymeric composite material (brittle or ductile) and the natural bond between the polymer matrix material and strengthening materials [22][23]. Table 6  indicates the difference of the means is not significant at (0.05) level. This meaning that the weight fractions of cinnamon powder reinforced with poly methyl methacrylate was negative on the elongation percentage at break properties. From tensile properties, can be observed the pure poly methyl methacrylate has the lowest tensile strength and elasticity coefficient (51 MPa and 1.5 GPa), respectively. Ultimate tensile strength and elasticity coefficient raise with increase weight fraction cinnamon powder into poly methyl methacrylate resin reach to (62 MPa and 3.7 GPa) respectively, while the elongation percentage at break decrease (3.9% to 2.7%) with an increasing weight fraction of cinnamon powder.

IV. Flexural Strength
The flexural strength of poly methyl methacrylate strengthening with various weights fraction cinnamon powders is shown in Figure 11. Results showed that the weight fraction (2%, 4%, 6%, 8%) has influences were significantly in flexural strength of Poly Methyl methacrylate resin, where the sample (PMMA+8% Cinnamon powder) has higher values of flexural strength (96 MPa). Lastly, the percentage improvement of the flexural strength was (23.8 %). These resultly may be attributed to dispersal of the reinforced material in a matrix resin material, which negatively affects the grade of conversion that leads to a raise nonreactant monomer that acts as plasticizer [24][25].    Figure 12 shown flexural modulus values results acquired of flexural test of the bio-composite 12.

V. Flexural Modulus
Can be observed from this figure, it the values of flexural modulus increases with increased weight fraction cinnamon powder in poly methyl methacrylate resin bio-composite. This is because the regular , randomly distribution and ease penetration poly methyl methacrylate resin outof the filler (cinnamon powder) to forming strong adherence at interfaces between matrix resin with strengthening material , all of these reasons result in increased flexural modulus with each increase in the weight fraction of the particles [26]. The presence of 8% cinnamon powder increases the value of the flexural modulus to (6.4 GPa) compared with the value of the flexural modulus (2.0 GPa) of the pure sample.

VI. Impact Strength
This difference in impact strength of the biocomposites with 2%, 4%, 6%, 8% of cinnamon powder are shown in Figure 13. This Figure clearly indicates that the impact strength improves with the added weight fraction by 2%, 4% and 6% cinnamon powder, while decreases with addition weight fraction by 8% cinnamon powder. The sample (poly methyl methacrylate+6% Cinnamon) showed approximately 47.9% increment in impact strength from pure poly methyl methacrylate. The reason increasing the impact resistance is that the strong bond between reinforcement material and resin material causes formation of molecular bonds that prevent crack propagation through polymer composite materials [8]. The value of impact strength decreases when cinnamon powder is added by 8% weight fraction because the increase in surface area of reinforced materials and the increase in the stress, leading to the possibility of crack growth. Also, at high concentrations of the weight fraction reinforcing material effect on the interface area, thus reducing the energy dissipation during the test [27&28].