Belete Baaye MSc in fiber science and Technology EiTEX, BDU

1. BAHIR DAR UNIVERSITY
ETHIOPIAN INSTITUTE OF TEXTILE AND FASHION TECHNOLOGY
First year Msc in Fiber science and technology
For Natural fibers course
Review on characterization of a novel natural cellulosic fiber from
prosopis juliflora bark
By፡ Belete Baye
Submitted to:
Rotich Gideon
Submission date:
24,December, 2018
EiTEX, Bahir Dar University

2. I
Contents
List of figures..................................................................................................................................................................... II
ABSTRACT....................................................................................................................................................................... 1
1. Introduction................................................................................................................................................................ 1
2. Materials and methods ............................................................................................................................................... 1
2.1. Extraction of PJ fibers......................................................................................................................................... 1
2.2. Characterization of the fiber.............................................................................................................................. 2
2.2.1. Bark anatomy:............................................................................................................................................ 2
2.2.2. Tensile strength:......................................................................................................................................... 2
2.2.3. Chemical composition:............................................................................................................................... 2
2.2.4. FTIR spectroscopy ...................................................................................................................................... 2
2.2.5. X-ray diffraction (XRD) ............................................................................................................................... 2
2.2.6. Thermogravimetric analysis (TGA)............................................................................................................. 2
2.2.7. Morphology analysis by SEM ..................................................................................................................... 3
3. Result and discussion................................................................................................................................................. 3
3.1. Anatomy of the prosopis juliflora fiber.............................................................................................................. 3
3.2. Mechanical properties of PJF............................................................................................................................. 3
3.3. Chemical analysis............................................................................................................................................... 4
3.4. FTIR analysis....................................................................................................................................................... 4
3.5. XRD analysis ....................................................................................................................................................... 4
3.6. Thermal analysis................................................................................................................................................. 5
3. Conclusion ................................................................................................................................................................. 5
Reference ........................................................................................................................................................................... 6

3. II
List of figures
Figure 1: photograph of PJ plants ...................................................................................................................................... 2
Figure 2: Bark of prosopis for morphology study.............................................................................................................. 2
Figure 3: reinforced sandwich of PJF composite............................................................................................................... 2
Figure 4: Transverse section of the PJ bark showing several successive cylinders of fibers............................................. 3
Figure 5: The PJF as viewed under a polarized microscope.............................................................................................. 3
Figure 6: FTIR spectrum of the PJF in the frequency of 400–4000 cm−1. ....................................................................... 3
Figure 7:X-ray spectrum of the PJF................................................................................................................................... 4
Figure 8: TG and DTG curves of the PJF .......................................................................................................................... 4
Figure 9: Broido’s plot of the PJF ....................................................................................................................................... 4

4. 1
Abstract
A Bark fiber botanically known as “Prosopis juliflora(PJ) has selected for this review in order to understand
its morphological, chemical and physical properties. The PJF has higher cellulose (61.65 wt %) content and
lower density (580 kg/m3). Crystallinity Index (CI) of JPF calculated from X-ray diffraction studies is 46%.
The surface of PJF was examined using SEM for observing its surface morphology. Its Structural and
Chemical composition has long-established by (FT-IR). The thermal behavior of PJFs was determined using
TG and DTG curves from Thermo gravimetric (TG) analysis. Findings show that this fiber has irregular
circular configurations with the cell wall structure and thermally stable until 217°C. Thus the
characterization results confirmed the possibility of using PJF for the manufacturing of sustainable fiber
reinforced polymer composite.
1. Introduction
Natural fibers can play a major role in composite industry due to their eco-friendly properties. They are
renewable, biodegradable, low density, low hazard properties and economical rather than synthetic fibers [1].
Nowadays much importance is being given to the development of recyclable and environmentally sustainable
composite materials than ever before due to increasing environmental benefits [2]. They are obtained from
different plants such as coconut, flax, jute, hemp, kenaf, and sisal [3]. The essential properties of natural
fibers are continuous, lesser in diameter and low spiral angle of the cellulose arrangement. The cellulose in
the fiber is shielded with non-cellulose constituent (hemi-cellulose, lignin, pectin, and wax). Surroundings
and age of the plant control the chemical configuration of fibers [2]. A Plant called prosopis juliflora
containing natural fibers is typically grown in various regions with fluctuating ambient conditions. The
morphological, structural and thermal characterizations of Cellulosic prosopis juliflora fiber (PJF) are well
sydied in this paper. The main objective of the review is to understand the characteristic features of the PJFs
using Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Fourier Transform Infrared
Spectroscopy (FT-IR), and Thermo Gravimetric Analysis (TGA).From this review it can be concluded that
PJFs can act as a better reinforcement for the polymer reinforced matrices and add significant value to the
future research.
2. Materials and methods
2.1. Extraction of PJ fibers
The extraction technique for the fiber is microbial degradation method. The barks of a twisted stem of PJ
plant as shown in fig 2 are immersed in water for a maximum of 15 days. Then they became soft due to the
microbes effect and the inner and outer layers detached. The outer layer became disposed off where as the

5. 2
inner layer retained on the stem for separation of the fibers by traditional comber having long and fine metal
teeth.
2.2. Characterization of the fiber
2.2.1. Bark anatomy:
The bar anatomy of PJF can be analyzed by a polarized microscope (Nikon, Japan) with small piece of the
bark.
2.2.2. Tensile strength:
The maximum strength can measured with single fiber test using universal testing machine in accordance
with ASTM D-3379-75 standards with n=30 PJFs at cross overhead of 1mm/min for 50mm guage length for
tensile strength test and n=10 PJFs embedded in unsaturated isophthalic resin (C6H4 (CO2H) 2) with a density
(in order to improves thermal resistance and mechanical performance, as well as
resistance to chemicals and water) at cross over head of 0.1mm/min for 20mm guage length and 5KN
capacity load cell for all tests.
2.2.3. Chemical composition:
Cellulose, hemicelluloses and lignin contents, wax content, and moisture content of PJF were determined
using the standard test method. The chemical compositions of other bark fibers used for comparison were
obtained from different literatures. [2]
2.2.4. FTIR spectroscopy
FT-IR spectra were recorded using a Model FTIR-8400S spectrum, SHIMADZU,Japan)for chemical
structure(free functional groups) with a wave range of to .
2.2.5. X-ray diffraction (XRD)
It was used to determine the cristalinity of PJF by using Powder X-ray diffraction methods.
2.2.6. Thermogravimetric analysis (TGA)
TGA was performed by using Jupiter simultaneous thermal analyzer (Model STA 449F3, NETZSCH,
Germany) to measure the mass and transformation with a flow rate of 20 mL/min to prevent any unwanted
oxidative decomposition. Measurements were inspected with the aid of TG-DSC Alumina crucible with lid
in programmed temperature range from room temperature to 1000°C at a heating rate of 10° C/min (Samson
and Blanka 2015).
Figure 3: reinforced
sandwich of PJF composite
Figure 2: Bark of prosopis
for morphology study
Figure 1: photograph of PJ
plants

6. 3
2.2.7. Morphology analysis by SEM
a thin gold layer coated (prevent charge accoumulation during examination) specimen was visualized by
SEM (Model SU1510, HITACHI, Japan) with an accelerated voltage of 30kv and attainable vacuum level of
0.0015pa.
3. Result and discussion
3.1. Anatomy of the prosopis juliflora fiber
Analysis of the PJF through polarized microscope showed thin dark tangencial layers of phloem fibers
divided in the direction of their length in to thick fiber blocks by different wavy rays. They are too small
(30µm thick) and obsolete (rare) on the outer layer (60-100µm wide) and become thicker (40µm) and wider
(200-3000µm) gradually) through the inner zone. There are about 15 cylinders of such fibers coming one
after another in an uninterrupted sequence as shown in fig 4 blow. The fiber contains highly lignified outer
primary wall and a secondary wall coated with mucilage substance which is a viscid material naturally
present on the barks of PJ plants. When the fibers are treated with toluidine blue (a thiazine dye,
C15H16ClN3S), its outer primary wall became dark green, while the inner secondary wall purple. Up on
phloroglucin (1, 3,5trihydroxybenzene, C6H3 (OH) 3), the primary wall appeared Red due to the presence of
lignin, while the secondary wall remain unchanged. Under polarized microscope observations, the primary
wall appeared bright blue, but the secondary wall remained color less or appeared in different colors. The
single fiber has thin primary and secondary walls (diameter and thickness (20 µm, 5–8 µm and 10–12 _m,
respectively) as compared to other bark single fibers of flax(17.8–21.6 µm),hemp(17–22.8 µm), jute(15.9–
20.7 µm), kenaf(17.7–21.9 µm) and ramie(28.1–35 µm).[2]The S1, S2 and S3 layers of the fiber were not
very distinct and the cell lumen was approximately 8µm in diameter as shown in fig 5 below.
3.2. Mechanical properties of PJF
Most of the time the cell wall structure (s1, s2, s3) and chemical composition largely affect the mechanical
properties of bark fibers. PJF has comparable tensile strength (558±13.4 MPa with1.77±0.04% of strain rate)
with other bark fibers of flax (500–900 MPa), hemp (690 MPa), jute (370±134 MPa), and ramie (915
MPa)[2]. It also has a similar microfibril angle (α) (10.64º±0.45º) with other the bark fibers like jute (8.1º),
Figure 6: FTIR spectrum of the PJF in
the frequency of 400–4000 cm−1.
Figure 5: The PJF as viewed under a
polarized microscope
Figure 4: Transverse section of the
PJ bark showing several successive
cylinders of fibers

7. 4
flax (5º), hemp(6.2º) and banana(11-12º).Its fiber –matrix interfacial shear strength(5.3±0.26MPa) was the
primary factor for stress transfer from matrix to fiber in composite structure.
3.3. Chemical analysis
The PJF has 61.65% cellulose which used as bond to withstand the hydrostatic pressure gradients of the fiber
and also has a degradable hemicelulose(16.41%content) which causes disintegration PJF fiber into
microfibrils and lower strength due to less linking effect. Its higher lignin (17.11%) content makes the fiber
less flexible as compared to other bark fibers. it has less wax (0.61%) content relative to hemp (2.3%) but
more relative to okra (0.3%) bark fiber that leads weak interfacial bond between fibers and polymer matrices.
Table 1: Comparison-of-chemical-compositions-of-the-PJF-with-bark-fibers-of-other-plants
Name of
fiber
Cellulose
(%)
Hemicelluloses
(%)
Lignin
(%)
Wax
(%)
Moisture content
(%)
Density(kg/
m3
)
Ash
(%)
Reference
PJF 61.65 16.14 17.11 0.61 9.48 580 5.2 Kommula et al. 2016
Jute 72 13 13 0.5 12.6 1460 0.5-2 Senthamaraikannan et al. 2016
Flax 81 14 3 1.7 10 1500 - Senthamaraikannan et al. 2016
Ramie 76 15 1 - 8 1500 -
Hemp 74 18 4 2.3 10.8 1480 - Senthamaraikannan et al. 2016
Kenaf 53.14 14.33 8.18 - - 1400 -
Hop stem 84±1.6 - 6±0.2 - - - 2±0.1
Okra 60-70 13.1-16.7 0.6-0.7 0.3 7.5-17 - -
3.4. FTIR analysis
As shown above, fig 6, the typical highest points of a wave (peaks) were attained between
in relation to O-H stretching and bending
frequencies. For PJF, the maximum stretching peack was O-H and for C-H links.
The different peaks for different functional groups were observed like C-O-C (ester group) stretch
at , C-O (carbonyl stretch at ) for acetyl groups in hemicelluloses and aldhydic
groups in lignin. This was comparable with the carbonyl region (C-O) of hemp fiber ( ), mulbury
bark (1643 and 1742 ), lignin of okra fiber C=C stretching of aromatic group (1517 ) peak stretch.
[2]
3.5. XRD analysis
The crystalline region of PJF was observed at diffraction angles of 18.12º(110) and 22.67º(200) as
shown in fig 7 above due to the cellulose crystalline regions.it has much lower(46%) CI (cristaline index)
than Jute (71%) and Hemp (88%) and much greater crystallite size (15nm) than flax (2.8nm) but closer to
ramie (16nm)[2].
Figure 8: TG and DTG curves of the PJF Figure 9: Broido’s plot of the PJF
Figure 7:X-ray spectrum
of the PJF

8. 5
3.6. Thermal analysis
Normally natural fibers have good thermal stability. The thermo gravimetric (TG) curve shown in Figure 8
indicates that the weight loss of fiber at temperature ranges between 33°C and 1000°C. 10%Weight loss
between 33°C and 149°C was due to evaporation of water present in the raw fiber (Samson Rwawiire and
Blanka Tomkova 2015). The degradation between 200°C and 300°C is due to thermal depolymerization of
non cellulose groups of hemicellulose. α-cellulose of PJF decomposed at 331.1°C but 321 ◦C, 308.2 ◦C,
298.2 ◦C and 309.2 ◦C for bamboo, hemp, jute and kenaf fibers, respectively. Above 110°C, the thermal
resistance of PJF has decreased gradually. Due to its complex aromatic structures, the decomposition of
lignin is at very slow rate within the whole temperature rates. But most of the time it decomposed at
540°C.The decomposition (oxidative degradation) of charred residual products occurred between 480.6 ◦C
and 676.6 ◦C. From the DTG curve (Figure 9), two maximum intensity peaks were observed; first one at
63.4°C and other was being 331.1°C with a large intensity. The first peak (63.4°C) corresponds to
suberin(An inert, impermeable, waxy substance present in PJF) and lignin fractions and the second (331.1°C)
associated with Cellulose content (Kathiresan et al. 2016).it has apparent activation energy Ea of 76.72
kJ/mol as shown in fig 9 above determined to understand the detailed kinetic parameter of the fiber.
3. Conclusion
In this review, the morphology, crystallinity, chemical composition, and thermal degradation and of PJF are
studied. The cellulose content (61.65%) is relatively high and low density (580 kg/m3) of PJF with improved
mechanical properties is chosen for composite reinforcement applications. The SEM micrograph confirms
that irregular circular structures increase the essential feature for the fiber with polymer matrix composite
manufacturing.The presence of good cellulose content of the fiber long-established through chemical and
FTIR analysis. The crystallinity index (CI) of PJF has found to be 46%, which shows the presence of
relatively high crystalline cellulose in the fiber. The TG and TDG of the PJF have found that the fiber is
thermally stable up to 217°C. These deserved properties persuasively showed the potential of PJF that make
them perfect alternative reinforcement material in polymer matrices and industrial applications.

9. 6
Reference
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structure, and mechanical properties of natural cellulose fiber from mendong grass (Fimbristylis globulosa).
Journal of Natural Fibers 1:333–51. doi:10.1080/15440478.2013.879087.
2. S.Saravanakumaretal.2016 Characterization of a novel natural cellulosic fiber from Prosopis juliflora
bark·journal of carbohydrate polymers 92:1928– 1933.DOI: 10.1016/j.carbpol.2012.11.064 ·
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Varada Rajulu. 2016. Extraction, modification, and characterization of natural ligno-cellulosic fiber strands
from napier grass. International Journal of Polymer Analysis and Characterization 21:18–28.
doi:10.1080/1023666X.2015.1089650.
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Physico-chemical, tensile, and thermal characterization of Napier grass (native African) fiber strands.
International Journal of Polymer Analysis and Characterization 18:303–14.
doi:10.1080/1023666X.2013.784935.
5. P. Balasundar, P. Narayanasamy, P. Senthamaraikannan, S. Senthil, R.Prithivirajan & T. Ramkumar
(2017): Extraction and Characterization of New Natural Cellulosic Chloris barbata Fiber, Journal of Natural
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