1. 1
Thermal and Crystalline behavior of injection moulded bagasse fiber
reinforced Polypropylene
Manish Kumar Lila, Inderdeep Singh
Department of Mechanical and Industrial Engineering, Indian Institute of Technology
Roorkee, Roorkee – 247 667, INDIA
E-mail: manish.lila@gmail.com
Phone: +91-9639633034
ABSTRACT
Natural fiber reinforced composites have made widespread impression in terms of numerous
engineering applications because of their excellent environmental and ecological aspects. In
the present research endeavor, the effect of bagasse fiber reinforcement on polypropylene has
been studied. Reinforced PP composites have sufficient weight difference as compared to
pure polypropylene. A decrease in crystallinity and increase in the weight is observed with
increase in fiber reinforcement. The experimental results also establish that washed bagasse
fiber contains sucrose residue, which will affect the properties of polymer when reinforced.
The present investigation proposes that the bagasse fiber reinforced PP composites are
potential candidate for replacing current injection moulded PP products.
Keywords: Bagasse Fiber, Polypropylene, Injection Moulding, XRD, TGA.
Introduction
Composites materials are intermediate materials, which are made up of two or more
distinct materials and combined in such a way, that it allows its constituents to remain distinct
and identifiable.
Generally, Polymer Matrix Composites are reinforced with either synthetic or natural
fibers. The cost associated with manufacturing of synthetic fibers is comparatively high and
the need of high energy in production, environmental pollution, regulatory laws and general
societal awareness on pollution, energy, and raw material waste have stimulated a rapid
growth of novel uses of natural fibers as reinforcements. Therefore, due the cost,
environmental and ecological aspects, the need and use of natural fiber as reinforcement is
increasing globally.
Fibers, which are obtained from natural sources or processed from natural sources, are
called natural fibres. For example: hemp, sisal, cotton, silk, wool, etc. Natural fibers are
lignocellulosic and hollow in nature and having comparable mechanical, thermal and
structural properties. A summary of the comparative study is shown in table 1. A few
mechanical properties of these fibers can be made comparable by proper chemical treatment
of fibers.

2. 2
Aspect Properties Synthetic Fiber Natural Fibers
Technical Mechanical High Moderate
Moisture Sensitivity Low High
Temperature Sensitivity Low Moderate
Environmental Resources Limited Unlimited
Production High Low
Recyclability Good Moderate
Pollution High Low
Economical Cost Moderate Low
Table 1: Comparative study between synthetic and natural fibers [1]
Bavan and Kumar [1] reviewed that the crops, which are cultivated in India and can
be used for fiber production are mainly Bamboo, Nettle, Coir, Cotton, Banana, Jute and Sisal,
while Bajpai et al. [2] compared the mechanical properties of various natural fibers with
PLA as matrix, which were fabricated by different processes. Lila et al. [3] reviewed about
easily available fibres, by-products and wastes from industries, technical properties and their
potential for civil engineering applications.
It can be seen from the table 2, that the major crop, which is produced in India, is
sugarcane, which is also convertible to fibrous form. An average production of white sugar
accounts for nearly 70 per cent of the total cane produced in the country. Approximately 15-
20 % sugarcane is utilized for gur and khandsari production and rest is utilized for other
purposes including paper and seed [4].
Table 2: Average production and Industrial use of various crops [1,4,5, 6]
Species Average Annual Production Use in Industry
World wide India
Bamboo 14 MMT 4.6 MMT Construction, Paper,
Textile
Jute 2.5 MMT 1.5 MMT Packing, Textile,
Construction
Coir 0.25 MMT 0.15 MMT Mattress, Mats,
Ropes
Cotton 25 MMT 5.5 MMT Textile
Banana* 70 MMT 23 MMT Food
Kenaf 0.45 MMT 0.18 MMT Packaging, Rope
Sugarcane 1.83 BMT 357 MMT Sugar, Paper,
Chemical
Experimental
Material and Methods
A homo-polymer of polypropylene in granule form (PROPEL 1350 YG) was procured
from Indian Oil Corporation Ltd. due to its comparable mechanical properties, low cost, use
and availability. Some properties of the selected polymer are listed in the table 3.

3. 3
Table 3: Thermal and Mechanical properties of PROPEL 1350 YG [Source: IOCL]
MFI (g/10min) Tensile
Strength (MPa)
Flexural
Modulus (MPa)
I- Impact
Strength (J/m)
Heat Deflection
Temp (°C)
35 36 1200 20 85
Raw bagasse has been collected from M/s Uttam Sugar Mills Limited, Libberheri,
Uttarakhand, and then dried, sieved, washed soaked and then dried again to remove
undesirable contents of dust, moisture, pulp, pith, leaves residue and uncrushed sugarcane
and to get the desired size of the fiber. Procured bagasse and modified (washed) bagasse
fibers are shown in figure 1.
Fig 1. Nascent Bagasse and washed bagasse fiber
ENDURA-60 Injection molding machine, with a maximum clamping force of 600
KN, stroke volume of 68 cm3
, screw L/D ratio of 21, manufactured by M/s Electronica
Plastic Machines Limited, Pune, has been used to fabricate the composites. The mold is
designed in such a way that in a single shot, it will fabricate the specimen for tensile testing,
flexural testing and impact testing.
Initially pure polypropylene (1350 YG) specimens were fabricated and then bagasse
fiber was reinforced and fabricated for checking the feasibility and operating values of the
parameters. Fibers and polypropylene granules were dried in hot air oven at 80°C for 4-5
hours to remove any type of moisture content, weighted and mixed for 10%, 20% and 30%
reinforcement and fabricated by using “direct injection moulding” process.
Thermal Analysis
Thermo Gravimetric Analysis (TGA) is a thermal analysis, which examines the mass
change of a sample as a function of temperature in the scanning mode. The analysis was
carried on EXSTAR TG/ DTA 6300 in Aluminium pan with Nitrogen gas environment. TGA
analysis of PP 1350 YG, bagasse fiber and fabricated specimen (10%, 20% & 30%) was
carried out, with a heating rate of 10°C/min.
X-Ray Diffraction Analysis (XRD)
XRD is a primary technique to determine the microstructure of the crystal, degree of
crystallinity, crystalline phases of polymers and to determine the crystalline orientation. The
analysis has been carried on X-ray diffractometer (BRUKER- D8) with Cu radiation
(wavelength of 0.1542 nm). Intensity has been observed between 5° and 60° (2θ angle range)
at 40 kV and 30 mA.
10 % 20% 30%

4. 4
Results and Discussion
Thermo Gravimetric Analysis
The results of TG analysis of polypropylene, bagasse fiber and bagasse reinforced
polypropylene are shown in the figures 2 (a,b):
Tertiary carbon atoms, which are present in polypropylene, are more prone to attack,
which reduce stability of polypropylene at high temperature. First weight reduction is
observed between 300°C to 400°C and at a temperature of 420°C, due to radiative heating
pilot ignition of polypropylene took place and a mass reduction rate of 3.07 mg/min has been
observed at 454°C.
(a) (b)
Fig 2: TG Curve for pure polypropylene & bagasse fiber reinforced polypropylene
In case of bagasse reinforced polypropylene, a two-stage decomposition has been
observed between 260°C to 480°C, with a mass reduction of 92-93% at a rate of 2.95mg/min
at 453°C, 2.27mg/min at 455°C and 2.25 mg/min at 458°C for 10%, 20% & 30%
reinforcement respectively.
The leftover (ash) in case of bagasse confirms the presence of lignin residue, which
can easily be seen on the graph, increasing with the % of bagasse reinforcement. Reducing
mass reduction rate and increasing temperature with an increase in bagasse reinforcement
indicates the presence of stable phase or change in the crystalline behavior of the composite.
This can be verified through XRD analysis.
X-Ray Diffraction Analysis
Commonly used polymers are a mixture of crystalline, semi crystalline, micro
crystalline and amorphous states. The convoluted diffraction patterns obtained for bagasse
fiber, polypropylene and bagasse reinforced polypropylene are shown in figure 3.1, 3.2 and
3.3 respectively.
The XRD pattern of untreated bagasse fiber reveals its microcrystallinity, in which
small crystallites cause peak broadening. Major crystalline peak for bagasse fibres is
observed at a 2θ value of 22.17°, with a d spacing of 4.00943 Å, which match with the
crystallographic plane (002, Bragg reflection). The expression for crystallinity index is given
as, , which is also known as Segal expression, given in 1959. [7]
260°C
480°C

5. 5
Where I002 is the intensity of diffraction at 2θ between 22° and 23° for cellulose I
(pure crystalline material), and IAm is the intensity, above the baseline, between the peaks at a
2θ value between 19° and 20° (19.2469Å), which represents the amorphous part of
lignocelluloses. By this expression, the crystallinity index for untreated bagasse fiber has
been found out to be 0.3652 or 36.52% crystalline.
Fig 3.1 XRD pattern for Bagasse Fiber Fig 3.2 XRD Pattern for Pure PP
Fig 3.3: XRD pattern for untreated bagasse reinforced polypropylene
Semi crystalline nature of polypropylene is revealed in its XRD pattern (Fig 3.2) with
4 peaks and the same pattern has been exhibited in reinforced polypropylene in fig 3.3.
Crystallinity of reinforced polypropylene is calculated by applying the Segal formula, which
is shown in table 4:
Table 4: Crystallinity of the materials
Material % Crystallinity
Untreated bagasse fiber 36.52
30% bagasse reinforced polypropylene 61.12
20% bagasse reinforced polypropylene 73.78
10% bagasse reinforced polypropylene 84.50
Polypropylene (PROPEL 1350 YG) 87.36

6. 6
Relative crystallinity of polypropylene is found out to be 87.36 which reduce with the
increase in % reinforcement as the peak intensity is reducing. Also a slight peak shift is
observed when polypropylene is reinforced with bagasse fiber.
Conclusion
It is observed that due to hydrophilic nature of untreated bagasse fiber, there is a
decrease in crystallinity with the increase in reinforcement of bagasse fiber. Also there is a
large difference in the crystallinity of polypropylene (87.36%) and untreated bagasse fiber
(36.52%). Crystallinity is a major factor for deciding the mechanical properties of a material,
therefore by chemical treatments, crystallinity of bagasse fiber can be improved, which will
lead to the improved crystallinity of bagasse fiber reinforced polypropylene and thereby
mechanical properties.
Lignocellulosic nature of untreated bagasse fiber has been revealed by TGA analysis.
This has been confirmed by two stage decomposition and the residual weight of higher
reinforced composite at high temperature. Chemical treatment of bagasse fiber can increase
the cellulosic properties, which may affect the mechanical properties in a positive way.
The present work shows a wide scope for further investigation for:
a. Chemical treatments of bagasse fiber and its effect on crystallinity and mechanical
properties of the composites.
b. Effect of crystallinity of matrix and reinforcement on the mechanical properties of
the developed composites.
c. Effect of the sucrose content of bagasse fiber on mechanical properties of
polypropylene when reinforced.
REFERENCES
[1] D. Saravana Bavan and GC Mohan Kumar, “Potential use of natural fiber composite
materials in India” Journal of Reinforced Plastics and Composites, 29(24) 3600–3613
[2] Pramendra Kumar Bajpai, Inderdeep Singh and Jitendra Madaan, “Development and
characterization of PLA-based green composites: A review” Journal of Thermoplastic
Material, 2012, 10.1177, 1-30
[3] Manish Kumar Lila, Faninder Kumar, Sanjay Sharma (2013), “Composite from Waste
for Civil engineering Application”, Journal on Material Science, Oct - Dec 2013, Vol 1,
No. 3
[4] Annual Report 2012-13, Indian Institute of Sugarcane research, Lucknow
[5] Pocket books on agriculture statistics 2013, Ministry of Agriculture, Department of
Agriculture and Cooperation, Directorate of Economics and statistics, New Delhi
[6] State of Indian agriculture 2012-13, Ministry of Agriculture, Department of Agriculture
and Cooperation, Directorate of Economics and statistics, New Delhi

7. 7
[7] L. Segal, J.J. Creely, A.E. Martin Jr and C.M. Conrad “An Empirical Method for
Estimating the Degree of Crystallinity of Native Cellulose Using the X-Ray
Diffractometer” Textile Research Journal October 1959 29: 786-794