In this study a bidirectional woven jute fabric with a density of 1.31 g/cm³ (Calcutta supply agency, Bangalore) was used as reinforcement. The areal weight of the fabric used is approximately 320 g/m². The matrix material system selected is an epoxy resin (Bisphenol-A MY 740 with density 1.16 g/cm³) supplied by Huntsman advanced materials, Bangalore, India. Araldite HY 918 and Anhydride DY 062 were used as hardener and accelerator. The commercially available titanium dioxide microfiller were obtained from Srivathsa enterprises, Bangalore. Its particle size ranged from 30 - 50 μm was used as filler material.

The composite samples were fabricated by hand lay-up method followed by compression using a hot press. Plain weave jute fabric, which is compatible to epoxy resin, is used as the reinforcement. The mixture of epoxy resin and hardener is mixed in the ratio 100:12 by weight. The stacking procedure consists of placing the fabric one above the other with the resin mix well spread between the fabrics. A porous Teflon film is placed on the completed stack. To ensure uniform thickness of the sample a spacer of size 3 mm is used. The mould plates have a release agent smeared on it. The whole assembly is pressed in a hydraulic press (0.5 MPa) and allowed to cure for a day at room temperature. After molding, post curing was done at 100˚C for 2 h using an air circulated oven. The laminate so prepared has a size 250 mm × 250 mm × 3 mm. To prepare the titanium dioxide (TiO₂) filled J/Ep composites, filler TiO₂ is mixed with a known amount of epoxy resin. The details of the composites prepared are listed in Table 1. Specimens were cut to the ASTM standards using water jet machining.

The measured densities of the unfilled and TiO₂ filled J/Ep composite samples are listed in Table 2. As indicated in Table 2, the density variation of TiO₂ filled J/Ep composites

are significant. It is observed that as the TiO₂ filler loading increases, the bulk density of J/Ep composite also increases. At the same time, density of TiO₂ is 4.1 g/cm³ which is higher that the J/Ep composite. Further, in can be seen the 10 wt% TiO₂ filled J/Ep is 1.44 g/cm³, which is highest when compared to other compositions of J/Ep composites.

The importance of mechanical properties is to quantify the role of fiber and filler in PMCs. Further, mechanical properties can also provide information on interfacial behaviour in composites, because the interaction between the fiber and/filler with the polymer matrix has a great effect on the mechanical properties. The mechanical properties such as tensile/flexural strength, modulus and deformation were reported in Table 2 and in Figures 1-4.

The typical load-displacement curves of unfilled and TiO₂ filled J/Ep composites are shown in Figure 1 and the measured mechanical test results are listed in Table 2. Referring to the tensile and flexural test results listed in Table 2, it can be seen that both modulus and strength increases up to 7.5 wt% TiO₂ filler loading. When the loading is above 7.5 wt%, it was found that the strength as well as modulus decreased rapidly. This could be due to more particles get agglomerated and poor interaction between TiO₂ particles and J/Ep composite.

It is observed from that the tensile strength of TiO₂ filled J/Ep composites is higher than that of unfilled J/Ep composite. The variation in the elongation at break, strength and modulus of unfilled and TiO₂ filled J/Ep composites are given in Figure 1 and Figure 2 respectively.

From the measured elongation of various J/Ep composites in Figure 1, the elongation was found to be higher in the case of unfilled J/Ep composite, while this value is lower in the of TiO₂ filled J/Ep composites. Regarding the elongation values of particulate

filled fiber reinforced PMCs, structural parameters of fiber/filler shape, ductility, strength, stiffness, and aspect ratio play an important role. These values are dominated by the fiber/filler breakage and matrix cracking. The ductile nature of jute fiber provides strain compatibility between fiber and matrix. The strain compatibility get reduced when TiO₂ filler is hybridized with jute fiber, elongation is decreased. In general, factors such as the extent of bonding of the filler to the epoxy matrix and the distribution of the filler in the epoxy matrix as well as the shape, size and content of the particulate fillers have been found to affect mechanical properties of the epoxy matrix composite. In the present work, it seems that there is a relation between the particles

loading producing elongation, as the loading increases the elongation at break decreases.

Figure 2 shows the tensile strength and modulus as a function of TiO₂ filler loading for the J/Ep composite specimens manufactured by hand lay-up followed by compression moulding. It can be seen that the tensile strength and tensile modulus of all J/Ep composites increased with increasing TiO₂ content; which showed that an increase in the rigidity of TiO₂ filled J/Ep composites would result in more resistance to higher load at low elongation. In TiO₂ filled J/Ep composite samples the higher strength and modulus indicates there was better filler-matrix bonding combined with the fact that the rigid TiO₂ filler was stronger than the jute fiber. The tensile strength is increased with increasing TiO₂ up to 7.5 wt%, because of the uniform dispersion of TiO₂ filler in J/Ep (Figure 2). However, the increase in tensile strength is marginal beyond 7.5 wt% of TiO₂ filler loading. This could be attributed to a slight agglomeration of TiO₂ particles in J/Ep. The improvement in the J/Ep composite tensile properties by using small amount of TiO₂ filler may be attributed to the improvement of the interfacial interaction. TiO₂ particles have higher rigidity than epoxy and sufficient particle/matrix adhesion as well as good bonding between fiber and matrix should be attributed for the interfacial interaction improvement. This investigation is mainly focused on TiO₂ filler loading rather than unfilled J/Ep composite, taking the 7.5 wt% TiO₂ loading into J/Ep there is about 23% increase in the tensile strength.

Elastic modulus is mainly dependent on the matrix deformation of the composite and increases as the slope of the load-deformation curve at the initial stage and is practically not much influenced by the interfacial strength between fiber and matrix. Generally, the addition of TiO₂ filler and jute fiber reduces the elongation at break because of the lower elongation at break values of TiO₂ filler and jute fiber compared to that of epoxy matrix at the filler loading 0 - 10 wt%. Comparing the results, it can be seen that TiO₂ filled J/Ep samples show improved mechanical properties, confirming the effect of TiO₂ filler inclusion. The addition of TiO₂ particles causes a dispersion of these particles in the matrix which impede to the propagation of failure along the loading direction. Thus the failure would propagate easily in those directions where the dispersed concentration is less leading to increased tensile strength, modulus and lower elongation. Fuqua and Ulven studied the role of MAPP on tensile properties of corn chaff fiber reinforced polypropylene composite materials [39] . They also studied the effect of different silane treatments on corn chaff fiber and distilled dried grains reinforced PP composite materials. It was concluded that 5 wt% MAPP yielded the optimum tensile and modulus properties for the PP composites. They also concluded that the strength reduction in higher MAPP loading was due to poor interaction between the compatibilizer and the fiber/matrix system. Similar observations were also found from our present investigation for TiO₂ filled J/Ep composites.

PMCs used in structures are likely to fail in bending and therefore the development of new fiber and particulate filled PMCs with improved flexural characteristics is necessary. Flexural mechanical test was performed to evaluate the strength, modulus and deflection of the unfilled and TiO₂ filled J/Ep composites.

The flexural properties of these composites are shown in Table 2 and the typical load-deformation curves are shown in Figure 3. Flexural properties like strength and modulus of unfilled and TiO₂ filled J/Ep composites are shown in Figure 4. The flexural strength of unfilled J/Ep composite is 64.2 MPa and increases with increase in TiO₂ filler loading. Modifying the J/Ep composite with different TiO₂ loading improved both flexural strength and modulus. In the case of 7.5 wt%, TiO₂ particles caused a maximum increase in the flexural strength (64.2 to 99.34 MPa) as well as modulus (3.17 to 3.62 GPa). The maximum flexural strength and modulus increase is about 55% and 14 5 respectively, when compared to unfilled J/Ep.

As discussed earlier, the fiber and filler interface in PMCs plays a major role in the improvement of the mechanical properties. Stresses transfer and elastic deformation from the matrix to the fiber and fillers are governed by the interface quality. Due to the higher rigidity of TiO₂ particles compared to epoxy, the deformation comes from the polymer. Up to 7.5 wt%, the TiO₂ particles are able to induce further mechanisms of failure without blocking matrix deformation. On the other hand, when filler loading exceed 7.5 wt%, large number of particles get agglomerated and reduced the matrix deformation. These results indicate that there is no significance of increasing the filler loading beyond 7.5 wt%.

SEM micrographs of fracture surfaces of unfilled and TiO₂ filled J/Ep composites are shown in Figure 5(a) and Figure 5(b). Figure 5(a) shows the unfilled J/Ep composite after tensile testing in which a smooth fracture surface as well as cracks in different planes of matrix (Figure 5(a)), more fiber breakage in the loading direction, pull-out of fibers in the transverse direction (Figure 5(a)) can be seen. This is an indication of a brittle fracture of the J/Ep composite. It can be observed that the fibers were cut

perpendicular to fiber axis (bottom portion of micrograph, Figure 5(a)), few fibers damaged in the length direction and also relatively poor bonding with the epoxy matrix. This indicates that a relatively small amount of energy was consumed to fracture the J/Ep samples.

Figure 5(b) shows lower and higher magnified SEM images of J/Ep composite after tensile testing for 7.5 wt% of TiO₂ filler loading, respectively. When TiO₂ introduced into J/Ep, the fracture morphology is different from that of unfilled J/Ep. From Figure 5(a), it can be observed that the matrix surface is rough, more cracks in different planes, good bonding between fiber/filler and matrix as well as less fiber breakage (Figure 5(b)). This result indicates the resistance of the material and emphasizes that the ultimate strength is at 7.5 wt% of TiO₂ in J/Ep composite.

SEM micrographs of bending test failed fractographs of TiO₂ filled and unfilled hybrid composites were shown in Figure 6(a) and Figure 6(b). Figure 6(a) and Figure 6(b) shows SEM pictures of flexural fractured surfaces of JE and JE-7.5TiO₂ samples at 50x and 500x magnifications respectively. From Figure 6(a), it can be clearly observed the jute fiber pull out and debonding between the reinforcement and matrix material. The lack of adhesion between the pulled out fibers and the resin is also visible from the Figure 6(b). The agglomeration is the collective stacking or collection of fibers together in the matrix which reduces the strength by non-uniform stress transfer. The fiber- matrix adhesion, dispersion and orientation of fibers, fiber agglomeration, and presence of air voids these are the influential factors for reduction of strength of the fiber reinforced composite.

Abrasive wear performance results are reported as wear volume loss of J/Ep composites; the greater the wear volume loss, the lower the abrasion resistance. The wear volume loss for the unfilled and TiO₂ filled jute fabric epoxy composites as a function of abrading distance at two different loads of 23.5 N and 47 N are shown in Figure 7(a) and Figure 7(b) respectively. It is clear that the abrasion resistance of all J/Ep composites

increased with increasing TiO₂ content; this is because of improved filler/matrix adhesion and good interaction between filler and matrix upto 5 wt% of TiO₂loading and beyond this loading, TiO₂ particles removed during three-body abrasion leading to increased wear volume loss. Further, it is observed that there is a near-linear trend of volume loss with an increasing abrading distance (Figure 7(a) and Figure 7(b)). The highest volume loss is seen with unfilled J/Ep composites while the lowest is seen for 5 wt% TiO₂ filled JE composite. The volume loss is higher in (7.5 and 10 wt%) TiO₂ filled J/Ep as compared to 5 wt% TiO₂ filled ones, indicating the good bonding between filler and fiber with the matrix. With the increase in filler loading, the wear volume loss of the composites also increases. Wear resistance is better in J/EP with 5 wt% TiO₂ and it could be due to the uniform dispersion of TiO₂ particles in the matrix. Higher filler loading >5 wt% in the epoxy matrix did not protect the fibers from damage and hence increased the wear volume loss.

The wear volume strongly depends on the applied load and abrading distance for all the composites. With an increase in applied load from 23.5 N to 47 N there is an increase in the wear volume, due to the fact that the apparent contact area is greatly increased at higher applied load of 47 N. This increase in contact area, allows a large number of sand particles to encounter the interface and share the stress. This, in turn, leads to increase in the wear volume. Among the composites studied, the better abrasion resistance was achieved at 5 wt% TiO₂ filled J/Ep composite. This is attributed to the fact that, in 5 wt% TiO₂ filled J/Ep composite, the dispersion of filler is more or less uniform and better adhesion due to surface modification of fillers and fairly good interaction between the matrix and fiber/filler.