ABSTRACT
Starch is a natural polymer which possesses many
unique properties and some shortcoming simultaneously. Some synthetic polymers
are biodegradable and can be tailor-made easily. Therefore, by combining the
individual advantages of starch and synthetic polymers, starch-based completely
biodegradable polymers (SCBP) are potential for applications in biomedical and
environmental fields. Therefore it received great attention and was extensively
investigated. The research aimed to evaluate the
physical and thermal properties of various potential starch, i.e. cassava, and
polyvinyl chloride. Granule size, thermal property, and functional group of
starch were determined by FTIR.
TABLE OF CONTENTS
Title Page i
DECLARATION
ii
CERTIFICATION
iii
DEDICATION
iv
ACKNOWLEDGEMENT
v
Table of Contents
vi
List of Figures
viii
List of Abbreviations
ix
ABSTRACT
x
CHAPTER ONE
1.0 INTRODUCTION 1
1.1Types of
biodegradable polymers
2
1.2 Synthetic
polymers 2
1.3
Naturally Occurring Biodegradable Polymers 3
1.3.1
Starch 4
1.4. Biodegradation test 5
1.5. Mechanical properties 5
1.6 AIM OF THE WORK
6
1.7
OBJECTIVE OF THE WORK
7
1.7 STATEMENT OF THE
PROBLEM
7
CHAPTER TWO
2.0 LITERATURE REVIEW 8
2.1
STARCH BLENDING
8
2.2
P0LYVINYL CHLORIDE (PVC)
10
2.3
STARCH/PVC BIODEGRADABLE BLEND 10
CHAPTER THREE
3.1
MATERIALS AND METHOD 14
3.1
MATERIALS
14
3.1.1 Equipments and Reagent
14
3.2 METHODS
14
3.2.1 Extraction
of starch
14
3.3 Dry matter (DM) content of starch, pulp and
flour:
15
3.4 Preparation of the Starch/PVC blends
16
CHAPTER FOUR
4.0 RESULTS AND DISCUSSION 17
4.1
Results 17
4.2
FTIR result of cassava starch 17
4.3
FTIR result of PVC 17
4.4
FTIR result of cassava starch blended with PVC 18
4.5 Discussion 19
4.6 Fourier Transform Infrared (FTIR) OF STARCH AND PVC 19
4.7 FTIR
analysis of starch
20
4.8 FTIR OF PVC
20
CHAPTER
FIVE
5.0 CONCLUSION, RECOMMENDATION AND REFERENCE 22
5.1 Conclusion 22
5.2
Recommendations 22
5.3 References 23
List
of Figures
Figure Description Page
1.0
Chemical structure of starch. 4
2.0
Chemical structure of PVC
8
3.0 extraction of starch
13
3.1 flour production 13
4.0 FTIR result of cassava
15
4.1 FTIR result of PVC 16
4.3 FTIR result of blended starch
and pvc 16
List of Abbreviations
FTIR Fourier Transform Infrared
PVC polyvinyl chloride
TGA Thermal
gravimetric analysis
TPS
Thermoplastic starch
CSV
Cassava starch
PLA Polylactic acid or
polylactide
PHB
Polyhydroxybutyrate
PHAs
Polyhydroxyalkanoates
PCL
Polycaprolactone
SCBP Starch-based
completely biodegradable polymers
CHAPTER ONE
1.0
Introduction
Biodegradable polymers are defined as polymers
that can be transformed into carbon dioxide, water, methane, and other products
with low molecular weight through a degradation process. The chemical process
of biodegradation is a series of reactions which occur through the presence of
living organisms,e.g., bacteria,fungi, yeast, algae, and insects at specific
conditions of light, temperature, oxygen (aerobic or anaerobic conditions), and
other variable (Encalada et al.,
2018).
Biobased and biodegradable polymers have an
extensive range of applications such as pharmaceutical, biomedical,
horticulture, agriculture, consumer electronics, automotive, textiles and
packaging, the last being perhaps one of the most common applications. Many
biodegradable poly mers are available, namely, polylactic acid or polylactide
(PLA), polycaprolactone (PCL), polybutylene adipate terephthalate
(PBAT), polyhydroxybutyrate (PHB), polyhydroxyalkanoates (PHAs), and
polyesteramide (PEA), (Soroudi et al.,
2013).. Even so, in some cases, The high cost of producing biodegradable
polymers prevents them from being used as substitutes for traditional polymers
(Girones et al., 2012).
An attractive alternative to the development
of biopolymers is the use of natural raw materials such as starch, lignin,
collagen, cellulose; moreover, starch offers a myriad of possibilities for
producing environmentally- friendly materials with potential for mass
commercial use (Gironès et al.,
2012). Starch is a polysaccharide that comes from tubers, roots, and grains.
Traditionally, starch has played an important role as a food ingredient, but it
is starting to be used in other applications, such as paper, pharmaceuticals,
and textiles (Laycock et al.,
2014).Native starches experiment high degradation rates, and many shortcomings
are associated with their limited mechanical properties and processability
problems (Tang & Alavi 2011)
Researchers have evaluated some methods of fulfilling all industry
requirements in order to improve functional properties. Various processes
including plasticization, physical, chemical, enzymatic and genetic
modifications have been studied (Neelam et
al., 2012), however, starch/biodegradable polymers blends seem to be the
most promising way to enhance the mechanical and thermal properties of native
starch (Marjadi 2011). Consequently, the
aim of this Work is to analyze the current state of the art of starch blends
with biodegradable polymers.
1.1
Types of biodegradable polymers
There are two types of polymers: synthetic and
natural. Synthetic polymers are derived from petroleum oil, and made by
scientists and engineers. Examples of synthetic polymers include nylon,
polyethylene, polyester, Teflon, and epoxy.Natural polymers occur in nature and
can be extracted. They are often water-based. Examples of naturally occurring
polymers are silk, wool, DNA, cellulose and proteins. (Vroman et al., 2009).
1.2
Synthetic polymers
As
well known, synthetic polymer materials have been widely used in every field of
human activity during last decades, i.e. post-Staudinger times (Jiang
et al 2019).
These artificial macromolecular substances are usually originating from
petroleum and most of the conventional ones are regarded as non-degradable (Neelam et
al., 2012). However, the petroleum resources are limited and
the blooming use of non-biodegradable polymers has caused serious environmental
problems. In addition, the non-biodegradable polymers are not suitable for
temporary use such as sutures. Thus, the polymer materials which are degradable
and/or biodegradable have being paid more and more attention since 1970s (Neelam et
al., 2012). Both synthetic polymers and natural polymers that
contain hydrolytically or enzymatically labile bonds or groups are degradable.
The advantages of synthetic polymers are obvious, including predictable
properties, batch-to-batch uniformity and can be tailored easily. In spite of
this, they are quite expensive. This reminds us to focus on natural polymers,
which are inherently biodegradable and can be promising candidates to meet
different requirements (Calmon
et al 1999).
Synthetic polymers materials come mainly from
petroleum sources; however these materials are able to decompose, which is
evaluated by standardized tests such asISO 1708, ASTM D6400,ASTM D6868, ASTM
D5338, and CSN EN 13432(Remar, 2011).
PVC has excellent gas barrier properties, high
strength, tear, adhesive, flexibility, water absorption, and bonding
characteristics (Priya et al., 2014).
Industrially, PVC is used in the manufacturing of biodegradable films as well
as adhesives and paper coatings the utilization of natural polymers for nonfood
(Encalada, et al., 2018).
However, PVC has drawbacks of high cost and
slow anaerobic degradation.The degradation rate strongly depends on the
quantity of residual acetate groups.The low biodegradation rate of PVC has
encouraged research into economically viable ways of blending PVA with
biodegradable polymers such as starch and protein.(Guo 2014).
1.3
Naturally Occurring Biodegradable Polymers
Uses can be traced back to ancient times. Skin
and bone parts of animals, plant fibers, starch, silk, etc.,are typical
examples of the natural polymers used in different periods of the human
history.the development of natural polymers was significantly hindered due to
the advent of low-cost petrochemical polymers. It was only about two decades
ago that intensive research on natural polymers was revived, primarily due to
the issues of environmental pollution and the depletion of fossil oils. Modern
technologies provide new insights of the synthesis, structures, and properties of
the natural polymers. These new findings have enabled developments of natural
polymers with novel processing characteristics and properties, which can be
used for many more advanced applications. This section deals with three major
natural polymers: starch, cellulose, and SP. All of them have primarily been
used as human and animal foods through history. New developments have allowed
them to be used as a material component in polymer blends and composites to
make biodegradable products.
1.3.1
Starch
Starch is the one of the most
abundant renewable, biodegradable, and natural polymers which it good for
alternative for synthetic polymers (Jiang et
al 2019). Starch is a biopolymer which
possesses many properties. It can be obtained from wheat, cassava, maize and
potatoes. Because it is a biodegradable polymer with well-defined chemical
properties, it has a huge potential as a versatile renewable resource for
various material applications in various areas (Benabid and Zouai 2016).
Starch is traditionally the largest source of
carbohydrates in human diet. Being a polysaccharide polymer, starch has been
intensively studied in order to process it into a thermoplastic polymer in the
hope of partially replacing some petrochemical polymers (Jiang and Zhang 2013). In its natural form, starch
is not meltable and therefore cannot be processed as a thermoplastic. However,
starch granules can be thermoplasticized through a gelatinization process. In
this process, the granules are disrupted and the ordered crystalline structure
is lost under the influence of plasticizers (e.g., water and glycerol), heat,
and shear. The resultant melt processable starch is often termed.
Figure 1.0 Chemical structure of starch.
1.4 BIODEGRADATION TEST
According to an ISO standard (ISO846-9 7) the
biodegradation of polymers is determined by the visual and/or measurement of
changes in mass and physical properties. There are also ASTM, DIN and other
standard methods. However, three different categories of test methods are
generally employed, depending on requirements (Calmon et al 1999). These include field tests, simulation tests and
laboratory tests. Each of these has its specific merits and demerits. In field
tests, the sample is placed in soil, a lake, river or compost and the physical
and chemical changes are monitored during the exposure time. Although this test
seems to most closely resemble actual environmental conditions, it has serious
disadvantages such as difficulties in controlling the test parameters and the
exact monitoring of changes occurring during testing. This test alone cannot
therefore prove the biodegradation of a polymeric product. In simulation tests,
the sample is placed in compost, soil or sea water in a laboratory controlled
system, so that test parameters such as pH, humidity and temperature can be
controlled (Solaro et al 1998). However, the most reproducible biodegradation
test is the laboratory test, where well-defi ned man-made media are inoculated
with mixed microbes or a particular strain of microbe to bring about the
biodegradation of a polymeric product.
1.5 MECHANICAL
PROPERTIES
The environmental concerns about the plastic wastes are
increasing, promoting the development of suitable alternatives for petroleum
based polymers, and starch is a promisor biopolymer from renewable resources to
produce biodegradable materials. However, the mechanical properties of these
materials are poor, being necessary the development of blends with others
biodegradable polymers to improve its mechanical and barrier properties (Zanela
et al 2019).
Polyvinyl alcohol (PVA) is a
synthetic water-soluble biopolymer, which possesses good mechanical and thermal
properties as well as good transparency and resistance to oxygen permeation.
Nonetheless, it has low degradation rates in some environments such as in soil
along with relatively high cost and poor water resistance owing to the presence
of hydroxyl groups in repeating units of PVA (Gupta et al.,
2013; Aslam et al., 2018). Blending PVA with starch gives rise to the high improvement of
biodegradability and cost reduction (Abdullah et al., 2017). Stach is a completely
biodegradable polymer in soil and compost, which is abundant as a spare storage
in plants with non-toxic and relatively low-cost features. However, it is hard
to process due to the high brittleness and limited flexibility (Abdullah & Dong 2019; Jolanta et
al., 2018).
The tensile strength, Young’s modulus, and
elongation at break were analyzed in a texture analyzer (model TA.XT2i, Stable
Micro Systems, England) with an initial distance between the grips of 30 mm and
a crosshead speed of 0.8 mm.s-1, according to ASTM D882-02 method, with some modifications. Ten samples
from each treatment (50 mm in length and 20 mm in width) were conditioned in a
desiccator with controlled relative humidity and temperature (53 ± 2% and 23 ±
2 °C respectively) for some hours before analysis. For puncture analysis, ten
specimens from each treatment were conditioned as described above and punctured
perpendicularly with a 6.35 mm diameter cylindrical probe at a velocity of 2.0
mm.s-1(Zanela et al 2018). The puncture elongation (mm) was
characterized as the maximum elongation supported by the sheet. The puncture
strength (N/mm) was obtained by dividing the maximum force by the sheet
thickness (Zanela et al 2018).
1.6 AIM OF THE WORK
The aim of the work was to study the biodegradable of starch,
extracted from cassava and biodegradable blends starch with polyvinyl chloride
(PVC). mechanical properties of extruded starch/polyvinyl chloride (PVC) Blending
starches aims to reduce the production cost; to improve barrier properties and
dimensional stability; to decrease the hydrophilic character of starch; and
increase its biodegradability.
1.7 OBJECTIVE OF THE WORK
·
To extract starch from cassava tuber.
·
To prepare starch and polyvinyl Chloride.
·
The blend starch and polyvinyl chloride also characterized using fourier transform infrared (FTIR)
·
This research aimed to evaluate the
physical and thermal properties of various potential starch, i.e. cassava, and
polyvinyl chloride. Granule size, thermal property, and functional group of
starch were determined by optical microscopy, DSC, and FTIR, respectively.
1.7 STATEMENT OF THE PROBLEM
Native
starches exhibit some limitations mostly related to mechanical integrity,
thermal stability, and humidity absorption. Because of these limitations,
starches are often blended with other materials to enhance their properties.
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