Effect of tungsten carbide on mechanical and tribological properties of jute/sisal/E-glass fabrics reinforced natural rubber/epoxy composites

Abstract

Natural fiber polymer composites have been largely used in applications like aerospace, automotive, marine, and other civil structures, where mechanical and tribological properties are of prime consideration. The performance of hybrid composites can be improved by using different natural fibers and adding particulate fillers to them. In this study, mechanical and tribological properties of jute/sisal/E-glass fabrics reinforcing matrix such as natural rubber and epoxy filled with different proportion of tungsten carbide (WC) powder were studied. Mechanical properties like tensile strength, flexural strength, impact strength, and also tribological behavior like two-body abrasive wear of composite were studied. Taguchi technique was employed for wear analysis. Results revealed that there is a significant change in the mechanical properties and enhancement of wear behavior was noticed due to the incorporation of filler (WC) particles.

Keywords

Jute sisal E-glass tungsten carbide natural rubber epoxy hand lay-up

Introduction

Advances in the area of materials science have bought forth intriguing and eco-friendly materials known as “natural fiber composites”. Hybridization of natural/glass fiber reinforced composites can give predominant and unique properties since it consolidates the most attractive properties of its constituents. Natural fibers are used in many applications because of its bio-degradability, low cost, low weight, specific strength, resistance to wear and corrosion. Most commonly used natural fibers for reinforcement in composites are jute, sisal, banana, hemp, etc, which are abundantly available in India. The glass fiber reinforced polymer can be used with natural fibers to enhance the mechanical properties as well as potential applications [1 –7]. In this view, this study helps to understand the hybridization of glass fibers with natural fibers for the strength enhancement and for specific applications.

Panthapulakkal and Sain [8,9] studied the mechanical and thermal properties of hemp/glass fiber reinforced polypropylene composites. From the obtained results, it was observed that the hybridization of glass fiber with hemp can improve the flexural and impact strength and also found increases in thermal property as well as water resistance. Sanjay and Yogesha [10] determined the mechanical properties of jute/E-glass fiber reinforced epoxy hybrid composites. The result of the tests showed that the incorporation of glass fiber in jute fiber composites enhances the mechanical properties and it leads to the increase of the utilization of natural fibers in various applications. Ramesh et al. [11] evaluated the mechanical properties of sisal–jute–glass fiber reinforced polyester composites. The incorporation of glass with jute and sisal composites shows the maximum flexural strength and impact strength attained from the pure natural fiber composites. Bisaria et al. [12] investigated the tensile, flexural, and impact properties of the randomly oriented short jute reinforced epoxy composites. Jute fiber of the various lengths 5, 10, 15, and 20 mm were reinforced into the epoxy matrix. Results reveal that the tensile property of epoxy resin was not increased, whereas flexural and impact properties of epoxy resin were increased by reinforcement of jute fiber. For the fiber length of 15 mm maximum tensile and flexural properties were found.

Braga et al. [13] compared the mechanical, thermal, and water absorption properties of the raw jute fiber and glass-fiber reinforced epoxy composites. The jute, glass, and epoxy percentage varied by 31–0–69 / 25–7–68 / 18–19–64. This study results showed that the incorporation of jute and glass fiber can increase the mechanical properties, but a considerable decrease in the properties of temperature and water absorption was also observed. Zhong et al. [14] focused on the surface microfibrillation of sisal fiber on the mechanical properties of sisal/aramid fiber hybrid composites. The result reveals that surface microfibrillation significantly influenced the mechanical properties. Sanjay et al. [15] reviewed the properties of natural/glass fiber reinforced polymer hybrid composites. This study showed that the incorporation of natural fibers with glass fiber can improve the properties and can be used as an alternate material for glass fiber reinforced polymer composites. Ahmed et al. [16] carried out experiments on natural rubber (NR) hybrid composites reinforced with silica, marble sludge (MS), rice husk (RHS). The result reveals that the addition of silica and RHS to their corresponding hybrid NR composites significantly improves the tensile strength, modulus, tear strength, and hardness.

Ngah et al. [17] conducted an experiment on the fracture energies of glass fiber (GF) composites with an anhydride-cured epoxy matrix modified using core-shell rubber (CSR) particles and silica nanoparticles. The use of CSR particles eliminates the incomplete phase separation that occur when using liquid rubber, and the addition of CSR or NS particles increases the fracture toughness and bulk polymer and GF composites. Ozdemir et al. [18] investigated the effect of nano-carboxylic acrylonitrile butadiene rubber (CNBR-NP) and nano-acrylonitrile butadiene rubber (NBR-NP) on the interlinear shear strength and fracture toughness of carbon fiber reinforced polymer composites (CFRP). The result showed that the fracture toughness of the CFRP laminates improved significantly with the nano-rubber modification of the matrix, which was justified by the changed morphology of the resins. Mohan et al. [19] studied the erosive behavior effect of tungsten carbide (WC) powder as filler in glass–epoxy (GE) composite. The vacuum-assisted resin-infusion technique was used for the preparation of composite specimen. The effect of different velocities on the resistance of wear was measured. The result showed that the addition of WC to GE composites improves the erosion resistance and it also shows the brittle erosive wear behavior.

Visconti et al. [20] investigated the wear behavior of composite materials, sliding under dry condition against steel counter face. The composite consists of glass fiber with epoxy resin filled with powder of silicon and WC prepared by hand lay-up method. From the results it was revealed that composite with the matrix filled with WC powder presented the highest value of wear resistance in the most severe wear conditions. Swamy et al. [21] studied the mechanical property of Al6061–WC composite. The result of this study revealed that with the increase in the WC particle content, there was significant increase in the ultimate tensile strength, hardness, and Young's modulus but reduction in its ductility. Harisha et al. [22] compared the unidirectional glass fiber and carbon fiber with an epoxy matrix composite and bidirectional glass fiber reinforcement for the erosive wear resistance of epoxy composites at the normal incidence. Silica sand was used to impact on the specimens, and the results showed better wear resistance by bidirectional glass fiber reinforced epoxy composite than the unidirectional reinforced composite. The objective of this work is to examine the mechanical and tribological properties of WC-filled composites with the combination of jute, sisal, glass, and rubber.

Materials and methods

Materials used

The essential parameters of the jute, sisal, and E-glass fabrics are shown in Table 1.

Table 1.

The parameters of jute, sisal, and E-glass fabrics.

Parameters		Jute fabric	Sisal fabric	E-glass fabric
Architecture		Plain	Plain	Plain
Density (g/cc)		1.46	1.33	2.55
Fabric weight (g/m²)		80	80	100
Young's modulus (GPa)		26.5	24	75
Elongation at break (%)		1.9	2	4.7
Orientation (Angle)	Horizontal (weft)	90°	90°	90°
Orientation (Angle)	Vertical (warp)	0°	0°	0°

Resin: Lapox L12 belongs to diglycidyl ether bisphenol (DGEBA) category having a density of 1.25 g/cc and having a viscosity of 9000–12,000 MPa at 250℃.

Hardener: K6 belongs to tryethyleltetramine (TETA). The weight percentage of hardener used is in the proportion of 10:1.

Rubber: Natural rubber is made up of isoprene compound and other impurities and water. Isoprene is an organic compound of polymers. Generally, rubber is harvested from the para rubber tree or others in the form of the latex, it is sticky and milk color. The rubber used is pigmented natural rubber (modulus of 500–700 GPa and density of 15.63 g/cc).

Tungsten carbide: It contains equal parts of tungsten and carbon chemical compound. It is generally used in composites as filler in the form of powder. Size of the powder is 2–3 µm, with modulus of 500–700 GPa (approximately) and with density of 15.63 g/cc.

Composite laminate fabrication

Composite laminates were prepared as per the weight percentage mentioned in Table 2, and the actual weight of the laminates is given in Table 3. Hand lay-up technique was used in this work to fabricate the composite laminates (Figure 1). Firstly, wax was applied on to the Mylar sheet, then the fabrics were cut according to the dimensions. By weighing the fabrics as per the composition of the composite laminates (Table 2), we have worked out the amount of resin add on and the WC powder percentage (Tables 2 and 3). Initially, a calculated quantity of resin was mixed with an amount of hardener in the ratio of 10:1 with stirring at low speed to avoid generation of bubbles and vacuum. The rubber (if combination needed) was added to this mix with acetone and stirred. Fabrics of glass, jute, and sisal were cut to the dimensions of 330 × 330 mm². A brush and a plate were used to apply resin onto the fabrics and the rubber was blended in between the two fabrics with the adhesive nature of resin. For the fabrication of the composites, the layers of fabrics were placed one by one on the flat mold and then the resin was applied after placing each layer of fabrics, equally distributed by using brushes followed by hand lay-up. To maintain a 3 mm thickness, small plates were used to press the laminates up to 3 mm and the excessive resin was squeezed out. After applying the load, the laminates were allowed to cure at room temperature for up to 24 h.

Table 2.

Composition of the composite laminates.

Laminates	Matrix (wt%) (Epoxy)	Fabrics (wt%)				Filler (wt%) WC	Density (g/cc)
Laminates	Matrix (wt%) (Epoxy)	Glass	Jute	Rubber	Sisal	Filler (wt%) WC	Density (g/cc)
Combination 1: Glass + Jute + Epoxy
G-J-E	40	30	30	–	–	0	1.651
5WC-G-J-E	35	30	30	–	–	5	2.376
10WC-G-J-E	30	30	30	–	–	10	3.102
Combination 2: Glass + Rubber + Epoxy
G-R-E	40	30	–	30	–	0	1.486
5WC-G-R-E	35	30	–	30	–	5	2.212
10WC-G-R-E	30	30	–	30	–	10	2.937
Combination 3: Glass + Sisal + Epoxy
G-S-E	40	30	–	–	30	0	1.612
5WC-G-S-E	35	30	–	–	30	5	2.337
10WC-G-S-E	30	30	–	–	30	10	3.063
Combination 4: Jute + Rubber + Epoxy
J-R-E	40	–	30	30	–	0	1.159
5WC-J-R-E	35	–	30	30	–	5	1.885
10WC-J-R-E	30	–	30	30	–	10	2.610

G: glass; J: jute; S: sisal; WC: tungsten carbide; R: rubber; E: epoxy.

Table 3.

Composition of the laminates.

Samples	Materials	Fabrics weight (g)				Resin+ Hardener (g)	Filler weight (g)	Total weight of the plate (g)
Samples	Materials	Glass	Jute	Rubber	Sisal	Resin+ Hardener (g)	Filler weight (g)	Total weight of the plate (g)
0% WC	G+J	162	162	–	–	216	0	540
5% WC	G+J	233	233	–	–	272	39	777
10% WC	G+J	304	304	–	–	304	100	1012
0% WC	G+R	146	–	146	–	194	0	486
5% WC	G+R	217	–	217	–	253	37	723
10% WC	G+R	288	–	288	–	288	96	960
0% WC	G+S	158	–	–	158	210	0	526
5% WC	G+S	229	–	–	229	286	38	764
10% WC	G+S	300	–	–	300	300	100	1000
0% WC	J+R	–	113	113	–	152	0	378
5% WC	J+R	–	184	184	–	217	31	616
10% WC	J+R	–	256	256	–	256	85	853

Figure 1.

Fabrication of the composite laminates.

Experimental studies

Density measurement

The experimental densities of the composites were measured using a simple water immersion method. Distilled water was used for this test. For each sample analyzed, six measures were carried out and average values of density were recorded.

Tensile test

Tensile test was conducted to measure the material's strength when opposite force was applied. Poisson's ratio, stress, yield strength, Young's modulus, and strain were obtained from this test. The specimens were prepared and tested according to the ASTM D-3039 standard. The dimension of tensile specimen was 250 × 25×3 mm³. The tensile test was conducted on a 100 kN universal testing machine (UTM, Model: LR50 K, Lloyds Instruments Ltd) with data acquisition software. The tests were carried out at a loading rate of 2.5 mm/min at 25℃. Figure 2 shows the tensile tested specimens.

Figure 2.

Tensile tested specimens.

Flexural test

Flexural test comes under destructive testing methods; it is also called as three-point bending test. The dimensions (125 × 12.7 × 3 mm³) of the flexural specimen were made according to the ASTM D790-07 standard. The flexural test was conducted on the same UTM using flexural test fixture and a load cell of 10 kN. The span length of the specimens was 50 mm and the load was applied at the center at a loading rate of 2.0 mm/min. Figure 3 shows the flexural tested specimens.

Figure 3.

Flexural tested specimens.

Impact test

This test measures the impact resistance of the specimens for suddenly applied loads. The impact strength of the composite laminate specimens was measured by a digital izod impact tester. The specimens were prepared and tested according to the ASTM D-256 standard. The dimension of impact specimen was 63 × 12.7 × 3 mm³. The specimen was placed in a vertical position, in the form of a cantilever and the notch along the side of striker end. Figure 4 shows the specimens of impact test before testing.

Figure 4.

Impact test specimens.

Wear test

The tribological test was conducted to study various factors like friction, lubrication, and wear. To find the wear rate, abrasive wear test was generally employed. The test was conducted according to the ASTM G-99 standard. For this test, pin-on-disc apparatus was generally used. Abrasive paper of 100 grade was attached to the rotating disc and pin was held in a holder. Before starting the test, initial weight was measured and final weight was measured at the end of the test, and this difference between the initial and final weights gave the loss of weight due to wear. Figure 5 shows the specimens used for the abrasive wear test.

Figure 5.

Wear test specimens.

Results and discussion

Density variation

From Figures 6 to 9, it was observed that the density increases by the increase in the filler percentage, because the density of the filler (WC) is greater than the matrix. It was also observed that the combination of glass and rubber and jute and rubber shows lesser density values than the other two combinations.

Figure 6.

Density variation of G + J + E.

Figure 7.

Density variation of G + R + E.

Figure 8.

Density variation of G + S + E.

Figure 9.

Density variation of J + R + E.

Tensile strength

Generally, tensile strength of composites is mainly dependent on the interfacial strength of the resin and fiber rather than the modulus of elasticity [14]. The values of tensile strength composite laminates are shown in Figures 10, 12, 14, and 16. The load versus displacement plots of the composite laminates are shown in Figures 11, 13, 15, and 17. By general observations, the tensile strength of all combinations significantly increased with the increase in filler loading.

Figure 10.

Tensile strength variation graph for G + J + E.

Figure 11.

Load vs. displacement graph for G + J + E.

Figure 12.

Tensile strength variation graph for G + R + E.

Figure 13.

Load vs. displacement graph for G + R + E.

Figure 14.

Tensile strength variation graph for G + S + E.

Figure 15.

Load vs. displacement graph for G + S + E.

Figure 16.

Tensile strength variation graph for J + R + E.

Figure 17.

Load vs. displacement graph for J + R + E.

Jute was observed to have less tensile strength than the glass fiber, by comparison of G + R + E and J + R + E combinations with WC as filler. For 0% filler, J + R + E shows lesser tensile strength than G + R + E. For increase in filler loading from 0% to 5%, G + R + E shows nearly 63% increase in the tensile strength. For increase in filler loading from 0% to 5%, J + R + E shows nearly 30% increase in the tensile strength. By this observation, it is clear that the filler loading in J + R + E does not much affect the interfacial strength of jute, rubber, and matrix. But in G + R + E, its effects are in considerable amount. For increase in filler loading from 5% to 10%, G + R + E shows 29% and J + R + E shows 69% increase in the tensile strength. These result shows that for G + R + E combination, the interfacial strength of resin fibers is increased considerably for 5% filler loading, and after an increase in filler loading (10%) there is not much more variation. For J + R + E combination, the 5% filler loading did not show much effects but a considerably greater increase in tensile strength was observed in 10% of WC.

Comparison of glass with jute and sisal was carried out. The results showed that there was no filler G + J + E and G + S + E have only 19%, for 5% of WC shows 37% and for 10% of WC shows only 7%, difference in tensile strength. For 5% WC loading, G + J + E shows 28% and G + S + E shows 13% increase in the tensile strength. For 10% WC loading, G + J + E shows 35% and G + S + E shows 63% increase in the tensile strength.

Comparing both G+J+E and G+S+E showed same performance at 0% and 10% filler loading. But variation was observed in 5% filler loading. There was not much variation in 5% filler loading of G + S + E combination. For 10% filler loading, both showed considerable variation in the tensile strength.

Flexural strength

The values of flexural strength obtained for different samples are shown in Figures 18 to 21. By the observation of results, G + R + E and J + R + E were found to have 43% difference in their flexural strengths, and showed almost a similar variation for an increase in filler loading wt%. In G + S + E composites, there was not much variation in the flexural strength by variation of wt% of WC. G + J + E composites showed lot more variations; it showed an increase in the flexural strength on an increase in filler wt%. The flexural strength increased by 60% for increase in filler wt% from 0 to 5; for 5 to 10 wt% increase of filler only 19% variation was observed. It is because of the strong interfacial bonding of glass and jute fiber with fewer gaps. By adding fillers, these fewer gaps will be filled thereby causing a further increase in the flexural strength. For a further increase in filler wt% the fillers get stuck in fiber and cause lesser impact on increase in the flexural strength.

Figure 18.

Flexural strength variation graph for G + J + E.

Figure 19.

Flexural strength variation graph for G + R + E.

Figure 20.

Flexural strength variation graph for G + S + E.

Figure 21.

Flexural strength variation graph for J + R + E.

Impact strength

The impact energy is generally termed as the energy absorbed by the specimen before yield, and it shows “toughness” of the material. High toughness indicates well balance between strength and ductility. The impact strength of the composite laminates is presented in Figures 22 to 25.

Figure 22.

Impact strength variation of G + J + E.

Figure 23.

Impact strength variation of G + R + E.

Figure 24.

Impact strength variation of G + S + E.

Figure 25.

Impact strength variation of J + R + E.

In Figure 23, for G + R + E composites, an impact energy increase of 75% has been observed when the filler loading increases from 0% to 5% and only 8% increase is observed when the filler loading increases from10% to 15%. In Figure 25, for J + R + E composites, 9% increase in the impact energy is observed for a raise in filler loading from 0% to 5% while for the filler loading raise from 5% to 10%, there is a considerable increase (43%) in the impact strength. Therefore, the impact strength of these composites varies with filler loading (WC)%. There is not much variation observed in G + J + E composites (5%), but a lot of variation is observed in G + S + E composites. For WC increase from 0% to 5%, an impact energy increase of 34% is obtained while for a WC increase from 5% to 10% a 21% impact energy increase is achieved. When WC is added to the composites in a higher proportion, WC = 10%, both combination shows same impact energy increase; at 5% they show 16% increase and at 10% they show 45% increase in the impact energy. Table 4 summarizes the results of the mechanical properties.

Table 4.

Testing results of composites.

Laminates	Density (g/cc)	Tensile strength (N/mm²)	Young's modulus (GPa)	Flexural strength (N/mm²)	Impact strength (J)
Combination 1: Glass + Jute + Epoxy
G-J-E	1.651	61.82	3.20	98.15	3.80
5% WC-G-J-E	2.376	82.68	4.59	183.3	4.00
10% WC-G-J-E	3.102	118.8	5.58	222.7	4.20
Combination 2: Glass + Rubber + Epoxy
G-R-E	1.486	50.26	2.80	76.07	2.00
5% WC-G-R-E	2.212	97.14	3.84	118.6	4.40
10% WC-G-R-E	2.937	130.1	4.16	149.0	4.80
Combination 3: Glass + Sisal + Epoxy
G-S-E	1.612	49.62	2.44	31.38	2.40
5% WC-G-S-E	2.337	56.87	2.98	34.71	3.40
10% WC-G-S-E	3.063	109.7	3.56	35.38	4.20
Combination 4: Jute + Rubber + Epoxy
J-R-E	1.159	25.44	2.01	48.73	2.40
5% WC-J-R-E	1.885	34.55	2.12	74.65	2.65
10% WC-J-R-E	2.610	71.38	3.50	100.3	4.10

Two-body abrasive wear

Tribological test was performed to understand the wear behavior of all composite combinations on pin-on-disc machine. The wear test was conducted for 10 N and 20 N load for the abrading distances of 25 m, 50 m, 75 m, and 100 m. Experimental data on wear volume and specific wear rate for all combinations are tabulated in Tables 5 to 12 and plotted in Figures 26 to 33. By literature survey, it was observed that erosive behavior of G + E composites increased with the incorporation of WC [19,21]. This study shows a similar trend in the mechanical properties by incorporation of WC with all the combinations. Also, the specific wear rate decreases with the increase in abrading distance.

Table 5.

Wear tests of G-J-E for 10 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-J-E	5% WC-G-J-E	10% WC-G-J-E
25	0.0421	0.0395	0.0362
50	0.0552	0.0507	0.0479
75	0.0652	0.0611	0.0584
100	0.0711	0.0683	0.0652

Table 6.

Wear tests of G-J-E for 20 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-J-E	5% WC- G-J-E	10% WC- G-J-E
25	0.0516	0.0497	0.0483
50	0.0589	0.0571	0.0547
75	0.0680	0.0652	0.0634
100	0.0746	0.0713	0.0695

Table 7.

Wear tests of G-R-E for 10 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-R-E	5% WC- G-R-E	10% WC- G-R-E
25	0.0436	0.0401	0.0376
50	0.0540	0.0489	0.0456
75	0.0649	0.0597	0.0531
100	0.0700	0.0657	0.0613

Table 8.

Wear tests of G-R-E for 20 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-R-E	5% WC- G-R-E	10% WC-G- R-E
25	0.0649	0.0617	0.0601
50	0.0770	0.0734	0.0704
75	0.0884	0.0869	0.0843
100	0.0934	0.0913	0.0873

Table 9.

Wear tests of G-S-E for 10 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-S-E	5% WC- G-S-E	10% WC- G-S-E
25	0.0400	0.0361	0.0312
50	0.0580	0.0489	0.0451
75	0.0712	0.0611	0.0591
100	0.0879	0.0769	0.0711

Table 10.

Wear tests of G-S-E for 20 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	G-S-E	5% WC- G-S-E	10% WC- G-S-E
25	0.0456	0.0435	0.0406
50	0.0625	0.0602	0.0572
75	0.0746	0.0706	0.0691
100	0.0852	0.0812	0.0788

Table 11.

Wear tests of J-R-E for 10 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	J-R-E	5% WC-J- R-E	10% WC-J- R-E
25	0.0386	0.0351	0.0312
50	0.0529	0.0487	0.0458
75	0.0686	0.0585	0.0561
100	0.0780	0.0703	0.0649

Table 12.

Wear tests of J-R-E for 20 N load.

Abrading distance (m)	Wear volume (mm³)
Abrading distance (m)	J-R-E	5% WC- J-R-E	10% WC- J-R-E
25	0.0486	0.0471	0.0456
50	0.0596	0.0551	0.0538
75	0.0712	0.0681	0.0634
100	0.0818	0.0797	0.0761

Figure 26.

Specific wear rates of G-J-E for 10 N load.

Figure 27.

Specific wear rates of G-J-E for 20 N load.

Figure 28.

Specific wear rates of G-R-E for 10 N load.

Figure 29.

Specific wear rates of G-R-E for 20 N load.

Figure 30.

Specific wear rates of G-S-E for 10 N load.

Figure 31.

Specific wear rates of G-S-E for 20 N load.

Figure 32.

Specific wear rates of J-R-E for 10 N load.

Figure 33.

Specific wear rates of J-R-E for 20 N load.

By comparing the wear volume, it is evident that G+R+E shows more wear than others for 10 N and 20 N loading. All other combinations show wear volume between 0.04 and 0.06, but G+R+E combination shows wear volume in the range of 0.06 to 0.08 as shown in Figure 34. This is because of the presence of rubber, which easily comes out. In this combination, filler does not show any effects on the reduction of wear rate.

Figure 34.

Comparison of wear volume for 50 m distance at the load of 10 N and 20 N.

Scanning electron microscope analysis

The scanning electron microscopic (SEM) images were taken to observe the interfacial properties, internal cracks, and internal structure of the fractured surfaces of the composite materials. All the specimens were coated with conducting material before observing the surfaces through SEM. By observing all the SEM images, it can be seen that they have few voids and fiber pull outs.

Figure 35 shows G + R + E at 0% WC. Smooth surface of the glass fibers results in poor adhesion with the matrix and fillers. Figure 36 shows G + R + E at 10% WC, and they have better bonding than at 0% WC with some amount of fiber breakage, pull-outs, and random distribution of fibers is present. These are the reasons as to why the rules of mixture for tensile modulus and tensile strength does not validate. Rules of mixture validate for the uniform distribution of fibers, matrix and a perfect bonding exists between them, and the matrix are free from voids. Figure 37 shows the SEM image of J + R + E at 10% WC at 500 × magnification. It is observed that there is a good bonding between jute and rubber with matrix, and also there is uneven distribution of fiber and the fiber cracking. Figures 38 and 39 show the SEM images of G + J + E and G + S + E, respectively. In both the images, fibers are clearly differentiated. In glass–sisal combination, the fiber pull-outs are observed.

Figure 35.

SEM image of G + R + E at 0% WC.

Figure 36.

SEM image of G + R + E at 10% WC.

Figure 37.

SEM image of J + R + E at 10% WC.

Figure 38.

SEM image of G + J + E at 10% WC.

Figure 39.

SEM image of G + S + E at 10% WC.

Conclusions

An attempt was made to investigate the effect of WC as filler on the mechanical properties such as tensile strength, Young's modulus, flexural strength, and impact strength of four hybrid composites: G + J + E, G + R + E, G + S + E, and J + R + E.

The following are the findings of our investigation:

Without filler loading (WC=0%): The G + R + E composites shows higher tensile strength in comparison to J + R + E.

In filler loading (WC=5% and WC=10%): The G + R + E composites shows higher tensile strength in comparison to J + R + E composites.

Among the four hybrid combinations (with and without filler loading): The G + R + E composites shows higher tensile strength, but G + J + E composites show maximum flexural and impact strength. The J + R + E composites exhibits lowest mechanical properties.

From the results, it is evident that ductility, tensile, and impact strength were better in WC=10% than in WC=5%.

The G + J + E and G + S + E composites show variation at WC=0% and WC=5%, but their ductility, tensile, and impact strength are almost the same at WC=10%.

Increased flexural strength by an increase in filler loading was noticed in the G + R + E and J + R + E composites. But there is not much variation in the flexural strength of the G + S + E composites.

In the wear test, the wear rate was reduced by an increase in the percentage of WC. Also, the specific wear rate decreases with the increase in abrading distance.

From all these results, it was observed that the filler loading can increase the mechanical properties and decrease the wear rate.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

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