INVESTIGATION ON MECHANICAL PROPERTIES OF HEMP-E GLASS FIBER REINFORCED POLYMER COMPOSITES

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International Journal of Mechanical Engineering and Technology (IJMET)
Volume 7, Issue 3, May–June 2016, pp.182–192, Article ID: IJMET_07_03_017
Available online at
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=7&IType=3
Journal Impact Factor (2016): 9.2286 (Calculated by GISI) www.jifactor.com
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication
INVESTIGATION ON MECHANICAL
PROPERTIES OF HEMP-E GLASS FIBER
REINFORCED POLYMER COMPOSITES
Somashekar S M, Manjunath V, Gowtham M J, Balasubramaniam N S
Assistant Professor, Department of Mechanical Engineering,
C. Byregowda Institute of Technology, Thoradevandanahalli,
Karnataka–563126
ABSTRACT
Natural fiber composite is currently a leading module in the world of
composites. It is due to many of its features such as freely available, easy
processing, low cost, ability to replace usage of Glass fiber (Synthetic fiber),
better strength properties and ecofriendly. They find useful applications in
various fields from domestic to automotive sector as of now. Natural fibers
with good content of lignocellulose, low density, and better elongation
percentage are chosen for manufacturing of composites of above mentioned
applications. Unidirectional & Continuous natural fiber composites are said
to be anisotropic and having predominant mechanical properties. While
designing these composites out of many factors, amount or volume fraction of
fibers also considered carefully. In this study untreated continuous Hemp
fiber-Bi directional woven E Glass fiber reinforced hybrid polymer matrix
composite laminates are developed and tested for its mechanical properties
such as tensile, compression and flexural as per ASTM standards by varying
fibers proportions. The obtained results yields that natural fiber composites
performed equally or more than synthetic fibers such as Glass fibers.
Key words: Untreated Continuous Hemp Fiber, Fiber Proportions, Polymer
Matrix
Cite this Article: Somashekar S M, Manjunath V, Gowtham M J,
Balasubramaniam N S, Investigation on Mechanical Properties of Hemp–E
Glass Fiber Reinforced Polymer Composites. International Journal of
Mechanical Engineering and Technology, 7(3), 2016, pp. 182–192.
http://www.iaeme.com/currentissue.asp?JType=IJMET&VType=7&IType=3
1. INTRODUCTION
Among day by day advancement in the materials technology, composite materials are
emerged as new generation structural materials quenching the needs and demands of
rapid growing industrial, automotive and aerospace sectors. Composites are created

Investigation on Mechanical Properties of Hemp–E Glass Fiber Reinforced Polymer
Composites
artificially by combining two or more materials of different characteristics. Two main
constitutents are necessary for successful preparation of composite material, one is
reinforcing phase and other is matrix phase. Reinforcing phase is regarded as primary
load carriers also add strength to the composites, whereas matrix phase is continuous
meant for creation of bonding between the fibers and carry the load which is acted
upon it directly and passed it to the fibers. Reinforcing phase further implies as fibers,
flakes, whiskers & particulates etc. Composites are characterized by length, size,
orientation, volume/weight fraction of fibers and properties comprised by both fibers
and matrix. To enhance the properties of the composites more than one fiber is used
with single matrix, known as Hybrid Composites. Among various types of fibers used
in the preparation of composites Natural fibers plays predominant role.
Natural fiber Composites
In recent years, there has been an increasing environmental consciousness and
awareness of the need for sustainable development, which has raised interest in using
natural fibers as reinforcements in polymer composites to replace synthetic fibers
such as glass. Abundant availability, easy processing, low cost, ability to replace with
synthetic fiber, better strength properties and ecofriendly are the major reasons for an
emerging new interest in sustainable technology. Natural fibers, as reinforcement,
have recently attracted the attention of researchers because of their advantages over
other established materials. They find their useful applications in various fields from
domestic to automotive sector as of now. Natural fibers with good content of
lignocellulose, low density, and better elongation percentage are chosen for
manufacturing of composites of above mentioned applications. Unidirectional &
Continuous natural fiber composites are said to be anisotropic and having
predominant mechanical properties. Many types of natural fibers have been
investigated for use in plastics including Flax, Hemp, Jute, Sisal, Kenaf, Coir, Straw,
Ramie, Banana, Pineapple, Tamarind, Rice husks, Wheat, Barley, Oats, Cane, Cane
(Sugar and Bamboo), Grass reeds, Oil palm, Empty fruit bunch, Water hyacinths,
Penny wort, Kapok, Paper-Mulberry, Raphia, Pineapple leaf fiber and Papyrus.
The objective of this attempt is to merge the benefits of natural (Hemp) and synthetic
(E glass) fibers by developing hybrid composites with varying amount of fibers and to
carry out comprehensive performance analysis by subjecting to different mechanical
tests.
2. MATERIALS USED
Hemp fiber: Hemp fibers are finding increasing use as reinforcements in composite
materials, often replacing glass fibers. Found in the bast of hemp plant, these fibers
have specific strength and stiffness that are comparable to those of glass fibers, cost
effective and easy to process and recycle. Hemp fibers find applications in,
 Used in production of Automobile parts.
 Used as building construction product.
 Hemp ceramic composites are used as tails.
 Can be used for sporting goods, musical instruments, luggage, etc.

Table 1.1 shows typical physical and mechanical properties of hemp fiber [1] as reported by
different authors.
Table 1.1 Typical Physical and Mechanical properties of Hemp
E glass fiber: E–Glass comprises of one of the most important class of reinforcement
especially used in polymer composites. It has low thermal coefficient, low dielectric
coefficient and high electrical resistance. Its properties depend on additives and curing
agents.
Epoxy resin: Epoxy has good additive properties along with high mechanical
strength, low shrinkage, chemically resistant, high diffusion density, low viscous and
better electric insulation capacity. And it is easily reinforced with natural hemp, kenaf
and E glass fibers.
Table 1.2 Properties of Epoxy Resin
Properties Epoxy
Viscosity at 250μ(cP) 12000-13000
Density ρ (g.cmˉ³) 1.16
Heat distortion temperature HDT (ºC) 100
Modulus of elasticity E (GPa) 5
Bending strength (MPa) 60
Tensile Strength (Mpa) 73
Maximum elongation (٪) 4
Hardener
Araldite HY951 hardener was used as a binder during the fabrication. It has low
viscosity, cure at room temperature, good mechanical strength, Good resistance to
atmospheric and chemical degradation.
3. EXPERIMENTAL METHODOLOGY
Procedure for preparation of Laminates
 Each composite laminate consists of a well compound mixture of Epoxy, Natural
fibers and E glass fibers. The Natural fibers, Hemp and Kenaf are used in this
procedure are untreated and free from chemicals.
 An open mold made up of steel plate of dimension 300X300 mm is prepared
Properties Values
Length (ultimate) (mm) 8.3–14
Diameter (ultimate) (mm) 17–23
Aspect ratio (length / diameter) 549
Specific apparent density (gravity) 1500
Microfibril angel (Θ) 6.2
Moisture content (%) 12
Cellulose content (%) 90
Tensile strength (MPa) 310–750
Specific tensile strength (MPa) 210–510
Young’s modulus (GPa) 30–60
Specific Young’s modulus (GPa) 20–41
Failure strain (%) 2–4
Density (untreated)(g/ccm) 1.249
Table 1.4 Typical physical and mechanical properties of hemp

Composites
 Using rule of mixtures the various Fiber weight proportions are calculated to achieve
laminates with 20:80, 30:70 and 40:60 ratios with former being the ratio of Fiber by
weight and the latter being that of the Natural fiber/s and E Glass fibers.
 Natural fibers are cut in to required length of the mold
 Based on the weight proportion calculations appropriate amount of Natural fibers and
resin are weighed in the electronic balance.
 Half amount of weighed fibers is placed inside the mold as a first layer
 Epoxy resin 556 and the hardener HY-951 are mixed with a ratio of 10:1 before
impregnating the first layered natural fibers
 Apply a mixture of resin and hardener over first layered fibers.
 Woven E glass of 300gsm has cut into required mold size and placed over
impregnated fibers.
 Again suitable amount of resin and hardener mixture is applied over previously
placed E glass fiber
 Rest of the half amount of natural fibers is placed over impregnated E glass fiber as a
second layer and again mixture of resin and hardener is applied.
 The resin mixture is spread up around the corners uniformly by Manual layup.
 A dead weight is placed over the open mold and left for settlement.
 After sometime the laminate is extracted from the open mold and kept in suitable
temperature oven for curing.
 Likewise all cured laminates are collected and arranged in the form of stalk and
bagging is covered over the stalk.
 The bagging enclosed of stalk is connected to vacuum through hose, in order to avoid
formation of voids over laminate surface.
Procedure for preparation of specimens
A Wire Hacksaw blade was used to cut each laminate into specimens of required
dimensions according to ASTM standards Fig 1.13, Fig 1.14 and Fig 1.15. Tensile test
specimens are cut according to the ASTM D-3039 size of (250x25x4.5) mm to
measure the tensile characteristics Fig 1.16. For Compression test specimens were
made according to the ASTM D-3410 size of (50x50x4.5) mm to measure the
Compression characteristics of composites Fig 1.17 and for Bending test specimens
were made according to the ASTM D-790 size of (150x20x4.5) mm to measure the
Bending properties Fig 1.18. The No. of the test specimens per combination is two
and average strength has been taken from each respective testing’s.
Composition and Mass Proportions of Laminates
Proportions by mass of Hemp and E glass fibers and Epoxy required for
compounding:
1. Density of Hemp 1.249g/ccm
2. Density of Epoxy resin 1.11g/ccm
3. Density of E glass (300gsm 2.58g/ccm

Table 3.1 Details of the different laminates fabricated
Laminates
Wt. of
Hemp
(grams)
Wt. of
Kenaf
(grams)
Wt. of E
Glass
(grams)
Wt. of
Hardener
(grams)
Wt of
Epoxy
(gms)
Wt. of
laminate
(gms)
Thickness
of the
laminate
(mm)
HE 20%
H+EG+M
11:9:80
40 0 36 30.4 273.36 380 4.5
HE 30%
H+EG+M
19:11:70
60 0 36 22.4 203.63 322 4.5
HE 40%
H+EG+M
28:12:70
80 0 36 17.4 158.18 292 4.5
4. RESULTS AND DISCUSSIONS
4.1. Tensile Test Results
Dimensions of specimens : (common to all)
Overall length : L=250 mm
Gauge length : l=50 mm
Table 4.1 Dimensions of Tensile test specimens (before conducting test)
Composition Specimen Thickness, d (mm) Width, w (mm) Area, A (mm2
)
HE 20%
1 4.970 20.2080 100.790
2 5.080 20.630 104.800
HE 30%
1 5.220 19.830 103.510
2 5.020 20.790 104.360
HE 40%
1 4.910 20.470 100.500
2 4.830 25.740 124.320
Table 4.2 Tensile test results
Composition Specimen
Tensile
strength
(MPa)
Avg. Tensile
Strength (MPa)
Youngs Modulus
(MPa)
Avg. Youngs
Modulus (MPa)
HE 20% 1 22.444
23.863
238.87
221.8632 25.283 204.85
HE 30% 1 21.262
21.788
200.00
209.8012 22.314 219.60
HE 40% 1 23.216
23.125
174.39
142.6182 23.034 110.84

Composites
4.2. Compression Test Results
Table 4.3 Dimensions of Compression test specimens (before conducting test)
Composition Specimen Thickness, d (mm) Width, w (mm)
HE 20% 1 5.45 51.54
2 5.45 51.25
HE 30% 1 5.3 51.58
2 5.49 51.73
HE 40% 1 5.02 51.95
2 4.87 50.45
Table 4.4 Compression test results
Peak
Load
(N)
Avg Peak
Load (N)
Compression
strength (MPa)
Avg Compression
strength (MPa)
HE 20% 1 18420 16680 65.58 59.54
2 14940 53.49
HE 30% 1 7560 12030 27.65 42.88
2 16500 58.1
HE 40% 1 11400 13350 43.71 52.99
2 15300 62.27
4.3. Bending Test Results
Table 4.5 Dimensions of Bending test specimens (before conducting test)
Thickness,
d (mm)
Width, w
(mm)
Support Span , l
(mm)
HE 20% 1 4.970 20.280 100
2 5.080 20.630 100
HE 30% 1 5.220 19.830 100
2 5.202 20.790 100
HE 40% 1 4.910 20.470 100
2 4.980 20.820 100
Table 4.6 Bending test results-1
Composition Specimen Load (N)
Avg Load,
(N)
Deflection,
(mm)
Avg Deflection,
(mm)
HE 20%
1 274.60
186.333
6.483
5.025
2 98.07 1.434
HE 30%
1 127.49
176.5255
5.092
5.211
2 225.56 3.097
HE 40%
1 254.98
205.946
5.881
4.945
2 156.91 4.998

Table 4.7 Bending test results-2
Bending
Strength
(MPa)
Avg Bending
Strength (MPa)
Bending
Modulus
Avg Bending
Modulus,
(MPa)
HE 20% 1 82.23 54.92821 100.42
96.432 27.63 92.44
HE 30% 1 35.39 47.76572 88.64
87.032 60.14 85.42
HE 40% 1 77.50 61.54309 103.18
100.202 45.58 97.22
4.4. Comparative Analysis of Mechanical Attributes
Table 4.8 Comparative Analysis of Mechanical Attributes
Composition
Avg
Tensile
Strength
(MPa)
Avg Youngs
Modulus
(MPa)
Avg
Compression
strength
(MPa)
Avg Bending
Strength
(MPa)
Avg Bending
Modulus,
(MPa)
HE 20% 23.863 221.86 59.54 54.93 96.43
HE 30% 21.788 209.80 42.88 47.77 87.03
HE 40% 23.125 142.62 52.99 61.54 100.20
Graph 4.1 Average Tensile strength versus Percentage of Hemp+E glass+Epoxy (HE)
Composites
Reason: It is observed that 20% fiber proportion got maximum Tensile strength
out of three proportions which have been tested. Here Tensile strength drops down to
as low as 21.79 MPa for HE-30%. This can be attributed that the incompatibility of
Epoxy and Hemp, Hydrophilic nature of Hemp and contrasting Hydrophobic
characteristics of Epoxy. This results in the creation of voids, reducing the tensile
strength. As the amount of Hemp increases, this results in moderate and gradual
increase in Tensile strength.

Composites
Graph 4.2 Average Youngs Modulus versus Percentage of Hemp+E glass+Epoxy (HE)
Composites.
Reason: It is observed that 20% fiber proportion got maximum Youngs Modulus
out of three proportions which have been tested. The Youngs Modulus of the sample
keeps decreasing upon increasing of fiber proportion due to reduction in resin amount
which holds fibers together.
Graph 4.3 Average Compression Strength versus Percentage of Hemp+E glass+Epoxy (HE)
Composites.
Reason: It is observed that 20% fiber proportion got maximum Compression
Strength out of three proportions which have been tested. Here the Compression
strength drops down to as low 43MPa for HE-30% due to creation of voids. As the
amount of Hemp increases, this results in moderate and gradual increase in
Compression strength.
Graph 4.4 Average Bending Strength versus Percentage of Hemp+E glass+ Epoxy (HE)
Composites

Reason: It is observed that 40% fiber proportion got maximum Bending Strength
out of three proportions which have been tested. Here bending strength drops at 30%
fiber proportion due to incompatibility of Epoxy and Hemp, Hydrophilic nature of
Hemp and contrasting hydrophobic characteristics of Epoxy which results in creation
of voids. Any further addition of fiber reduces voids.
Graph 4.5 Average Bending Modulus versus Percentage of Hemp+E glass+Epoxy (HE)
Composites
Reason: It is observed that 40% fiber proportion got maximum Bending Modulus
out of three proportions which have been tested. Here bending Modulus drops at 30%
fiber proportion due to incompatibility of Epoxy and Hemp, Hydrophilic nature of
Hemp and contrasting hydrophobic characteristics of Epoxy which results in creation
of voids. Any further addition of fiber reduces voids.
5. CONCLUSIONS
The following conclusions are drawn from the present investigation:
 The composites with 20% Hemp and E glass fibers (HE-20%) were found to have
best tensile strength. i.e., 23.86 MPa, Youngs Modulus i.e., 222 MPa,
Compression Strength i.e., 60 MPa among all fiber proportions composites tested
here.
 The composites with 40% Hemp and E glass fibers (HE-40%) were found to have
best Bending Strength i.e., 62 MPa and Bending Modulus i.e., 100 MPa among all
fiber proportions composites tested here.
GRAPHS

Composites

REFERENCE
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[3] Sunil Kumar .M, Shivakumar H.R, S.G.Gopalakrishna and K.S Rai, Preparation
and Characterization of Areca Bast Fiber Reinforced Epoxy and Vinyl Ester
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5(12), 2014, pp. 55–65.
[4] Sudheer K V, Avinash N V, Pramod Kumar N and Umashankar K. S, Influence
of Recycled Rubber Filler on Mechanical Behaviour of Woven Glass Fiber
Reinforced Vinylester Composites. International Journal of Mechanical
Engineering and Technology, 5(9), 2014, pp. 56–61.
[5] S.Shankar, Dr.H.K.Shivanand, Santhosh Kumar.S, Experimental Evaluation of
Flexural Properties of Polymer Matrix Composites. International Journal of

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