For sample preparation the bamboos were collected from local area and five pieces of bamboo were soaked at water for 10 days. Then almost uniform bamboo fibers were extracted manually from those bamboos by knife and hammers and ABS polymer at grain form were collected from local market and then ABS sheets were made by Hot Press Machine keeping both plate at temperature 180˚C and Hydraulic press at 50 KN for 30 minutes.

FTIR spectra of the samples were recorded at room temperature by using a double beam IR spectrometer in the wave number range of 400 - 4000 cm⁻¹. In this experiment, the solid samples were finely pulverized with pure, dry KBr, the mixture is pressed in a hydraulic press to form a transparent pellet.

When the beam of light passes through the sample, it becomes less intense due to the absorption of certain frequencies. The absorbance of the sample at a particular frequency can be calculated as

$A=\log \left(\frac{I_0}{I}\right)$ (1)

where, I₀ and I are the intensity of beam before and after interaction.

The bulk density of composites was determined according to ASTM C-134-76 [30] . The bulk density of the composite was measured by taking the weight and dimensions of the sample by using the equation, Bulk density,

$D=W_s/V=W_s/\left(L\times W\times H\right)$ (2)

where, W_s is the weight, L is the length, W is the width and H is the height of the sample respectively.

Water absorption test was carried out according to ASTM D570-98 [31] . Rectangular specimens were cut from each sample with dimension of 2.5 × 1 cm. The samples were dried in an oven at 60˚C for 6 hours and were weighed. In order to observe the composites, all samples were immersed in water for 288 hours at room temperature. Excess water on the surface of samples was removed by tissue paper before weighing. The percentage of water absorption was determined by using the following Equation (2),

$W_g=\frac{W-W_o}{W_o}\times 100$ (3)

where W and W_o are the weight of the sample after and before soaking in water.

Tensile test of composites was carried out according to ASTM D 3039/D 3039 M-00 [32] and Figure 4 shows samples of different wt% of composites for tensile test. At first, the samples were dried into oven at 60˚C for 24 hours to remove moisture. Dimension of the samples were measured. The average dimension of the samples was approximately 105 mm × 7.5 mm × 4.5 mm. Gauge length of UTM was 50 mm and cross-head speed was 2 mm/min. Then the test specimen was gripped into the jaws of Universal Testing Machine with a 10KN load cell. The test was monitored with a computer through Q-mat professional (Tinius Olsen, UK) software. Tensile strength, yield strength, elongation (%), maximum force and elastic modulus were easily found from the software output. The average TS was obtained from the results of three samples for each percentage.

The Leeb hardness test of the composites was carried out with an H1000 portable hardness tester according to ASTM A956-06 [33] . The hardness test samples dimension was 109 mm × 9 mm × 4 mm approximately. The composite sample was placed over a cemented table using glycerin. By pressing the button, samples were hammered by carbide ball of Leeb’s tester. The ball bounces back from the samples. The electronic sensor recorded the rebound velocity. Average data was considered as the Leeb hardness of the sample.

Figure 5 shows the FTIR spectrum in the frequency range (400 - 4000 cm⁻¹) for different wt% of bamboo-ABS composites. Figure indicates that the major peaks for 15% BF-ABS composite at about 2922.32, 2857.93, 2237.32, 1639.90, 1457.09, 1025.48, 764.78 - 706.37 cm⁻¹ are due to the presence of C-H stretch, O-H stretch, C≡N stretch, C-O stretch, C=C stretch, C-H scissoring and bending, C-N stretch, C-H bend respectively [34] .

From the figure, it is observed that in the 5% BF-ABS composite, a new N-H bond appears, showing characteristic stretching behavior. This N-H bond is also present in the 10% composite. However, in the case of the 15% composite, an additional O-H bond is detected. Therefore, the incorporation of bamboo fiber into the ABS matrix results in the formation of two new functional groups: N-H and O-H.

Figure 6 shows the water absorption of bamboo fiber reinforced ABS composites as a percentage of dry weight after 288 hours immersion in water. The result shows the water absorption is higher for 15% wt composite and lower for 0% wt composite. It was noticed that the water absorption of 5% wt% composite is greater than 10%. The results suggest that polymer like ABS can absorb a small amount of water while BF reinforced ABS composite absorbs more water. Bamboo fiber is hydrophilic in nature due to the presence of polar group. Hydrogen bond occurs between the free hydroxyl groups of the cellulosic molecules with water molecule.

Figure 7 shows the variation in the density of bamboo fiber reinforced ABS composites. Figure 7 indicates that the bulk density of the prepared composites is not homogeneous. Bulk density of bamboo-ABS composites increased a little first, then it started to decrease with the addition of fiber content. When the fiber content reached at 20% it further started to increase. Bulk density is found to be high for 5 wt% and 20 wt% composites. Bulk density increased means the composite becomes denser. Therefore 5 wt% and 20 wt% composites may be considerable for heavy load application and the others can be used for light load application.

Figure 8 shows the tensile strength for different wt% of bamboo reinforced ABS composites. Figure 8 indicates that the tensile strength of the bamboo-ABS composites decreased with the increased of fiber up to 5%. After adding 10% fiber tensile strength increased slightly. Then for further addition of fiber content (up to 15%) tensile strength increased with the value 27.18 MPa for 15% BF reinforced composite. It might arise due to poor interfacial adhesion between fiber and polymer matrix. Tensile strength depends on number of factors—fiber loading, matrix strength, fiber adhesion between fiber and matrix, orientation of fiber etc. For short fiber, the interfacial bonding is important. Figure 9 shows the graph of average percentage of elongation vs different wt% of fiber content. The maximum value of percentage of elongation (%E) is for 5% and 10% and it is 5.60 and decreases for 15% composite. This increase in tensile strength can be affected by several factors. Fiber may have inferred with the crystallinity of the polymer matrix or voids might have been generated with the increase in fiber content of the composite, thereby contributing to the decrease in the tensile strength of the material [35] .

Figure 10 shows the comparisons graphs of Rebound Hardness (HL). It can be seen that maximum value of the Rebound Hardness (HL) is for 5% bamboo fiber reinforced ABS which is 700.56 HL. Then with the increase of wt% of bamboo fiber the rebound hardness decreases. It means that the 5% composite has lowest energy absorption capacity of load than the other three.