UNIVERSITI TEKNIKAL MALAYSIA MELAKA

THE POTENTIAL OF EPOXIDIZED NATURAL RUBBER AS HYDROPHOBIC

CONTRIBUTOR IN BIODEGRDABLE UREA FERTILIZER

This report submitted in accordance with requirement of the Universiti Teknikal

Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering

(Engineering Materials) (Hons.)

by

NOR ABIDAH BINTI ABDUL AZIZ

B050910044

900301-065136

FACULTY OF MANUFACTURING ENGINEERING

2013

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: The Potential of Epoxidized Natural Rubber (ENR) as Hydrophobic Contributor in Biodegradable Urea Fertilizer

SESI PENGAJIAN: 2012/13 Semester2

Saya NOR ABIDAH BINTI ABDUL AZIZ

mengakumembenarkanlaporan PSM inidisimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengansyarat-syaratkegunaansepertiberikut:

1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan

pertukaran antara institusi pengajian tinggi. 4. **Silatandakan ( ~)

D SULIT (Mengandungimaklumat yang berdarjahkeselamatanataukepentingan Malaysiasebagaimana yang termaktubdalamAKT A

D Er

TERHAD ~~~~~~a'\86~at TERHAD yang telahditentukanolehorganisasi/badan di

TIDAK TERHAD manapenyelidikandijalankan)

AlamatTetap:

No. 279, Jalan Besar,

Felda Padang Piol, 27040

Jerantut, Pahang

1.~ I .6 I 1.3 Tarikh : Tarikh: ---------------------

IHAM BINT1 MOHAM 0 Pensyw.h

Fakulti Kejuruteraan Pembuatan Un1vers1t1 Tekmkal Malays1a Melaka

2-4 I 6 I 13

•• Jikalaporan PSM m1 SULIT atau TERHAD, silalampirkansuratdaripadapihakberkuasa/ organisasiberkenaandenganmenyatakansekalisebabdantem pohlaporan PSM iniperludikelaskansebagai SULIT atau TERHAD.

I hereby, declared this report entitled “The Potential of Epoxidized Natural Rubber

(ENR) as Hydrophobic Contributor in Biodegradable Urea Fertilizer”.

Signature :………………………………………….

Author’s Name :Nor Abidah binti Abdul Aziz

Date :3th June 2012

DECLARATION

This report is submitted to the Faculty of Manufacturing Engineering of Universiti

Teknikal Malaysia Melaka (UTeM) as a partial fulfillment of the requirements for

the degree of Bachelor of Manufacturing Engineering (Engineering Material). The

member of the supervisory committee is as follow:

……………………………… (Principal Supervisor)

……………………………….

(Co-Supervisor)

APPROVAL

ABSTRAK

Objektif kajian ini adalah untuk menyiasat potensi ENR dalam penghasilan baja

terbiodegradasi urea berasaskan kitosan. Dalam kajian ini, campuran kitosan dan

getah asli terepoksida (ENR) digunakan sebagai pengikat untuk memanfaatkan sifat

biodegradasi dan ciri hidrofobik masing-masing. Kesan formulasi terhadap sifat baja

yang terhasil dikaji secara terperinci di dalam kajian ini. Terlebih dahulu, kitosan dan

ENR dicairkan di dalam cecair toluena dengan kehadiran bentonit sebagai pengisi.

Setelah pengelatinan, serbuk urea dicampurkan dan dikacau sehingga homogen

dalam jangka masa 20 minit kemudian dituang ke dalam piring petri untuk

dikeringkan di dalam ketuhar pada suhu ~60°C semalaman. Acuan digunakan untuk

memadatkan campuran dengan menggunakan penekan hidraulik untuk mendapatkan

saiz dan bentuk yang dikehendaki. Selepas pemprosesan, sifat fizik dan mekanik baja

diuji melalui penentuan ketumpatan, ujian biodegredasi, ujian penyerapan air, ujian

pengekalan air, ujian kekerasan dan ujian mampatan. Akhirnya, baja dianalisis untuk

sifat terma, sifat kimia dan morfologi dengan menggunakan permeteran kalori

pengimbasan kebezaan (DSC), pembelauan sinar-X (XRD), spektroskopi penjelmaan

Fourier infra-merah (FTIR), serakan tenaga sinar-X (EDX) dan kemikroskopan

elektron imbasan (SEM). Diakhir ujikaji ini, didapati peningkatan amaun ENR dapat

mengurangkan kadar penyerapan air ke dalam baja melalui pemampasan sifat

hidrofilik kitosan. Campuran 10pph ENR didalam kitasan berasaskan baja urea

menghasilkan baja urea terbiodegradasi yang mempunyai ketumpatan

sebanyak1.128g/cm3, manakala penyerapan air adalah sebanyak -7.73% dan

pengekalan air sebanyak 95.9%. Kekuatan mampatan dan kekerasan urea-ENR10

juga adalah paling rendah dengan masing-masing hanya0.559MPadan 39.53 Shore

D. Akhir skali,dengan kehadiran ENR tahap biodegradasi baja urea yanglebih

perlahan dapat dihasilkan. Ia diramal dapat meningkatkan prestasi pembebasan

nitogen ke persekitaran untuk baja pembebasan perlahan pada masa akan datang.

i

ABSTRACT

The objective of this research is to investigate the potential of ENR in preparation of

chitosan based urea fertilizer. In this research, mixture of chitosan and epoxidized

natural rubber (ENR) was used as binder to take advantage of their biodegradable

and hydrophobic characteristics, respectively. The effect of mixing formulation to the

properties of fertilizer was studied in detail. Firstly, the chitosan and ENR was

diluted in toluene with the presence of bentonite as filler. After gelatinization, the

urea powder was mixed and stirred until homogenous for 20 minutes. Then, the

gelatin was poured into a petri dish and left to dry in an oven at 60°C overnight.

Then, it is put in a mold and compressed using a hydraulic presser to obtain the

desired size and shape. After processing, the physical and mechanical properties of

the fertilizer was determined through density measurement, biodegradability test,

water absorption test, water retention test, hardness test and compression test.

Finally, the fertilizer was analyzed for thermal, chemical and morphological

properties by using differential scanning calorimetry (DSC), X-ray Powder

Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Energy

Dispersive X-ray (EDX) and scanning electron microscopy (SEM). At the end of this

research, it has been found the incorporation of ENR in biodegradable chitosan based

urea fertilizer has imparted the properties biodegradable properties to the

ENR/chitosan based urea fertilizer. A mixture of 10pph ENR in chitosan based urea

fertilizer produced biodegradable urea fertilizer with density low density of

1.23g/cm3 where as water absorption and water retention was -7.73 % and 95.9%

respectively. The compressivestrength and hardness of this sample werethe

lowestwith only 0.559 MPa and 39.53 Shore D, respectively. Finally, with the

presence of ENR slower biodegradability level of urea fertilizer was produced. It

ispredictedto improve the performance of nitrogen release to surrounding for future

slow release fertilizer.

ii

ACKNOWLEDGEMENT

I would like to convey my gratitude to Allah S.W.T for His generous blessing and

undying strength bestowed upon me during the course of this research.

Firstly, I would like to extend my heartiest gratitude to Dr. Noraiham Mohamad as

my supervisor who had given me guidance and support me during the research. And

not to be forgotten to other lecturers, my co- supervisor PM Dr. Azizah Shaaban, my

mentor Ms. Nadiah Hamid, my friends and other person whose name is not mention

here.

Last but not least, I would like to thank my lovely mother and father for their

support. With prayers and moral support from both of them, I have gained strength to

endure in this study. I also want thank to UTeM management especially from Faculty

of Manufacturing Engineering because giving me the opportunity to gain experiences

and knowledge during the research.

iii

TABLE OF CONTENT

Abstrak i

Abstract ii

Acknowledgement iii

Table of Content iv

List of Table viii

List of Figure x

List of Abbreviations xii

List of Symbol xiv

1. INTRODUCTION 1

1.1 Background 1

1.2 Problem Statement 2

1.3 Objective 4

1.4 Scope 4

1.5 Chapter overview 5

2. LITERATURE REVIEW 6

2.1 Fertilizer 6

2.2 Type of Fertilizer 8

2.2.1 Organic Fertilizer 9

2.2.2 Inorganic Fertilizer 10

2.3 Slow and Controlled Released Fertilizer 11

2.4 Urea Fertilizer 15

2.4.1 Urea 16

2.4.2 Urea Formaldehyde Fertilizer 16

2.5 Biodegradable Urea Fertilizer 17

2.5.1 Type of Biodegradable based Urea Fertilizer 18

iv

2.5.2 Properties of Biodegradable based Urea Fertilizer 21

2.6 Hydrophobic 22

2.6.1 Hydrophobicity of Biodegradable Urea Fertilizer 23

2.7 Chitosan 24

2.7.1 Chitosan based biodegradable urea fertilizer 26

2.8 Natural Rubber (NR) 28

2.8.1 Epoxidised Natural Rubber (ENR) 28

2.9 Granulation of Fertilizer 29

2.9.1 Type of granulation process 30

2.9.2 Dry Process 32

2.9.3 Wet Process 32

2.9.3.1 Drum Granulator 34

2.9.3.2 Pan Granulator 35

2.9.3.3 Mixer Granulator 36

2.9.4 Compaction Granulation 38

2.10 Properties of Fertilizer 40

2.10.1 Density 40

2.10.2 Water Absorption 41

2.10.3 Biodegradability 42

2.10.4 Compressive Strength 42

2.10.5 Hardness 43

2.10.6 Compositional Analysis 44

2.10.7 Morphological Analysis 45

2.10.8 Thermal Analysis 46

3. METHODOLOGY 49

3.1 Introduction 49

3.2 Raw Material 51

3.2.1 Urea 51

3.2.2 Chitosan 52

3.2.3 Epoxidised Natural Rubber (ENR) 53

3.2.4 Toluene 54

3.2.5 Bentonite 55

v

3.3 Characterization of Raw Materials 56

3.3.1 Determining of Particle Size Distribution by using Malvern

Particle Size Analyzer (PSA) 56

3.3.2 Identifying chemical structure materials by using Fourier

Transform Infrared Spectroscopy (FTIR) 58

3.3.3 Element analysis by using Energy Dispersive X-ray (EDX) 59

3.4 Preparation of ENR/chitosan based urea fertilizer 60

3.4.1 Synthesis of ENR/chitosan based urea fertilizer 60

3.4.2 Mixing of ENR/chitosan based urea fertilizer 60

3.4.3 Drying 61

3.4.4 Compaction 64

3.5 Testing and Analysis technique 66

3.5.1 Physical analysis 66

3.5.1.1 Density 66

3.5.1.2 Water Absorption 67

3.5.1.3 Water Retention 68

3.5.1.4 Biodegradability 69

3.5.2 Mechanical Analysis 69

3.5.2.1 Compression Test 69

3.5.2.2 Hardness test 71

3.5.3 Thermal Analysis 72

3.5.3.1 Differential Scanning Calorimetry (DSC) 72

3.5.4 Compositional Analysis 73

3.5.4.1 Fourier Transform Infrared Spectroscopy (FTIR) 73

3.5.5 Phase Analysis 74

3.5.5.1 X-Ray Diffraction (XRD) 74

3.5.5 Morphological Analysis 75

3.5.5.1 Scanning Electron Microscope (SEM) 75

3.6 Optimization formulation of ENR/chitosan based urea fertilizer by

using Translation and Ranking selection method 76

4. RESULT AND DISCUSSION 77

vi

4.1 Introduction 77

4.2 Raw Material Characterization 77

4.2.1 Particle Size Distribution 78

4.2.2 FTIR analysis 78

4.3.3 SEM/EDX analysis 83

4.3 Density Test 86

4.4 Water Absorption 87

4.5 Water Retention 90

4.6 Biodegradable test 93

4.7 Compressive strength of chitosan/ENR based urea fertilizer 95

4.8 Hardness Test in specimen 98

4.9 FTIR analysis of chitosan/ENR based urea fertilizer 100

4.10 SEM/EDX analysis of chitosan/ENR based urea fertilizer 102

4.10.1 Morphological analysis by SEM/EDX 102

4.10.2 Morphological analysis of samples ENR/chitosan based urea

Fertilizer 104

4.11 Thermal analysis of chitosan/ENR based urea fertilizer by using DSC 107

4.12 Crystalline/amorphous phase analysis by XRD 109

4.13 Optimum formulation of ENR/chitosan based urea fertilizer via

ranking method 112

5. CONCLUSION AND RECOMMENDATION 115

5.1 Conclusion 116

5.2 Recommendations 118

REFERENCES 119

APPENDICES

vii

LIST OF TABLE

Table 2.1 N-P-K description (Materials Handbook: A Concise Desktop

Reference, 2000) 7

Table 2.2 Classification of organic fertilizer (Tsukasamachi, 2003) 10

Table 2.3 Commonly used inorganic fertilizer (Wijgert, 2009) 12

Table 2.4 Organic based urea fertilizer (Jenjie et al., 2002) 20

Table 2.5 Granulation process (Article: Pharmaceutical Technology,

1998) 31

Table 3.1 Raw material 51

Table 3.2 Powder urea characteristic according to MSDS 51

Table 3.3 Chitosan characteristic (MSDS chitosan) 52

Table 3.4 Toluene characteristic according to MSDS 54

Table 3.5 Bentonite characteristic according to MSDS 55

Table 3.6 Fomulation of chitosan based urea fertilizer 60

Table 4.1 Particle size distribution of raw material 78

Table 4.2 Functional groups present in ENR, urea, bentonite and chitosan 80

Table 4.3 Purity of raw materials 85

Table 4.4 Density measurements of each composition 86

Table 4.5 Percentage water absorption of each composition 89

Table 4.6 Detail percentage of water retention of each composition 92

Table 4.7 Compression strength of each composition 97

Table 4.8 Hardness of each composition 99

Table 4.9 Melting Temperature and enthalpy transition before

and after degradation for each composition 108

Table 4.10 The desired characteristic of biodegradable urea fertilizer 112

Table 4.11 The ranking process 114

viii

LIST OF FIGURES

Figure 2.1 Uniform pellet shape (Intellectual Property Corporation

Malaysia, 2002) 11

Figure2.2 Outlook of the SRF over a period of 8-9 months

(Green Feed, 2007) 13

Figure 2.3 Diffusion of water soluble nutrients by the biodegradable

superabsorbent polymer (Yamuna et al., 2012) 15

Figure 2.4 Hydrophobic interaction (Baker, 2011) 23

Figure 2.5 Chitosan structure (Kumar, 2000) 25

Figure 2.6 (a)-(f) SEM Micrograph of chitosan filled compounds of

rubber at 10 phr chitosan loading taken at different

magnification 27

Figure 2.7 Performic epoxidation ENR (Yoksan, 2008) 29

Figure 2.8 Principle of granulation (Aulton, 2012) 30

Figure 2.9 Chilsonator (Dry Granulation Process, 2005) 32

Figure 2.10 Illustrates the granule growth phenomenon

(Agrawal et al., 2011) 33

Figure 2.11 Drum Granulator (Ullmann’s Agrochemicals, 2007) 34

Figure 2.12 Pan Granulator (Ullmann’s Agrochemicals, 2007) 36

Figure 2.13 High speed mixer granulator (Kejohn, 2009) 37

Figure 2.14 Diagram of a typical compaction / granulation system

(Vent et al., 2004) 39

Figure 2.15 The effect of the amount of AM on water absorbency

(Wu et al., 2007) 42

Figure 2.17 Working Principle of FTIR 45

Figure 2.18 SEM working principle (Sperling, 2006) 46

Figure 2.19 SEM micrographs of dynamically cured

60/40 ENR-30/PP TPVs with sulphur system

(Nakason et al., 2008) 46

ix

Figure 2.20 DSC heat denaturation 48

Figure 3.1 Flow chart 50

Figure 3.2 Urea powder 52

Figure 3.3 Chitosan powder 53

Figure 3.4 Epoxidized Natural Rubber 54

Figure 3.5 Toluene liquid 55

Figure 3.6 Bentonite powder 56

Figure 3.7 Particle Size Analyzer 57

Figure 3.8 Fourier Transform Infrared (FTIR) 58

Figure 3.9 Schematic diagram of principle of EDX

(Goldstein et al., 2002) 59

Figure 3.10 Mixing sequence of ENR/chitosan based urea fertilizer 62

Figure 3.11 Final drying product ENR/chitosan based urea fertilizer 63

Figure 3.12 Drying oven 64

Figure 3.13 Manually hydraulic press 65

Figure 3.14 Mould of manually hydraulic press 65

Figure 3.15 Specimen of Fertilizer 66

Figure 3.16 Electronic Densimeter 67

Figure 3.17 Water absorption test 68

Figure 3.18 Specimen in container prior to test 69

Figure 3.19 Universal testing machine 70

Figure 3.20 Compression features 70

Figure 3.21 Specimen at compression test 70 Figure 3.22 Test point at hardness tester 71 Figure 3.23 Specimen at Hardness Tester 71

Figure 3.24 Hardness Tester 71

Figure 3.25 Differential Scanning Calorimeter 72

Figure 3.26 XRD instrument 74

Figure 3.27 The sputter gold coat (LEICA EM SCD005) instrument 75

Figure 3.28 Scanning electron microscope 75

Figure 3.29 Sample sputtered with thin layer gold 75

Figure 4.1 Volume (%) versus Particle Size (μm) for (a) chitosan,

(b) bentonite and (c) urea 79

x

Figure 4.2 FTIR spectrum of urea 81

Figure 4.3 FTIR Spectrum of Chitosan 81

Figure 4.4 FTIR spectrum of ENR 82

Figure 4.5 FTIR Spectrum of Bentonite 83

Figure 4.6 SEM/EDX spectrum of chitosan 84

Figure 4.7 SEM/EDX spectrum of urea 84

Figure 4.8 SEM/EDX spectrum of bentonite 85

Figure 4.9 Density of each composition 86

Figure 4.10 Percentage water absorption versus time 88

Figure 4.11 Physical diagram for samples 0,3,5,7 and 10 pph chitosan

after 360 seconds absorb water 90

Figure 4.12 Percentage water retention versus time 91

Figure 4.13 The physical changes of composition ENR based chitosan urea

fertilizer. (From left: urea-ENR0 until urea-ENR10) 93

Figure 4.14 Percentage weight loss versus time 94

Figure 4.15 Compressive strength versus composition 96

Figure 4.16 Fracture failure of composition

(a)ENR-1(without ENR loading)

(b)ENR-5(highest loading of ENR) 97

Figure 4.17 Hardness versus composition 99

Figure 4.18 FTIR spectra of (a) urea and (b) Sample urea-ENR10 101

Figure 4.19 SEM/EDX for urea-ENR0 103

Figure 4.20 SEM/EDX for urea-ENR10 104

Figure 4.21 Surface morphology of urea-ENR0 105

Figure 4.22 Surface morphology of urea-ENR10 110

Figure 4.22 XRD patterns of (a) ENR, (b) bentonite, (c) chitosan, (d) urea

with (e) urea-ENR10 respectively 111

Figure 4.23 XRD patterns of (a) urea-ENR0, (b) urea-ENR5 and

(c) urea-ENR10 116

Figure 4.24 The combination amorphous and crystalline region 112

xi

LIST OF ABBREVIATIONS

ENR - Epoxidised natural rubber

N - Nitrogen

P - Phosphorus

K - Potassium

C - Carbon

O - Oxygen

H - Hydrogen

Ca - Calcium

Mg - Magnesium

S - Sulphur

DSC - Differential scanning calorimetry

Tg - Glass transition temperature

FTIR - Fourier transform infrared

SEM - Scanning Electron Microscopy

SRF - Slow-release fertilizer

CRF - Control release fertilizer

IBDU - Isobutydine diurea

CO2 - Carbon dioxide

UF - Urea formaldehyde

PUFs - Polyurethane foams

(NH4)2SO4 Ammonium sulphate

ASTM The American Society for Testing of Materials

ISO - The International Standards Organization

NR - Natural rubber

AM - Acrylamide

xii

LIST OF SYMBOL

ms-1 - Meter per second

% - Percentage

kW - Kilo Watt

min - Minute

kg - Kilogram

mm - Millimeter

μm - Micrometer

kN - Kilo Newton

MPa - Megapascal

xiii

1.1 Background

Fertilizers are chemical compounds applied to promote plant and fruit growth (Bahera et

al.., 2009). According to Akelah et al. (1996), fertilizers are one of the most important

products of the agrochemical industry. They are added to the soil to release nutrients

necessary for plant growth. Artificial fertilizers are inorganic fertilizers formulated in

appropriate concentrations and the combinations supply three main nutrients: nitrogen,

phosphorus and potassium (N, P and K) for various crops and growing conditions. N

(nitrogen) promotes leaf growth and forms proteins and chlorophyll. P (phosphorus)

contributes to root, flower and fruit development. K (potassium) contributes to stem and

root growth and the synthesis of proteins (Mandal et al. and Gu et al. 2009).

El- Rafie et al. and Byung et al. (1996) has found method of reducing nutrient losses

involves the use of controlled-release fertilizers. These fertilizers can be physically

prepared from the granules of the soluble fertilizers by coating them with materials,

which reduce their dissolution rate. Meanwhile, slow release fertilizers are made to

release their nutrient contents gradually and to coincide with the nutrient requirement of

a plant. These fertilizers can be physically prepared by degradability coating granules of

conventional fertilizers with various materials that reduce their dissolution rate (Ge et al.

2002).

INTRODUCTION

CHAPTER 1

1

Therefore, this project is intended to study the potential of epoxidized natural rubber

(ENR) as hydrophobic contributor in biodegradable urea fertilizer. The formaldehyde

was replaced with the mixture of ENR and chitosan as hydrophobic and biodegradable

contributor, respectively. A fertilizer granule was produced through compaction and

drying process. Then, the granule was characterized for physical, mechanical, thermal,

chemical, phase and morphological properties.

1.2 Problem Statement

In urea fertilizer, some percentage of nutrients consist of nitrogen (N), phosphorus (P)

and potassium (K) is lost to the environment and cannot be absorbed by plants, causing

not only substantial economic and resource losses but also very serious environmental

pollution. The losses are due to leaching, decomposition and ammonium volatilization in

soil, handling and storage (Trenkel at al. (1997) and Saigusa et al. (2007).

Recently, the use of slow release fertilizers has become a new trend to save fertilizer

consumption and to minimize environmental pollution (Wu et al., 2008 and Guo et al.,

2005). Due to its polymeric cationic, biodegradable, bioabsorbable, and bactericidal

characteristics, chitosan (CS) nanoparticle is an interesting material for use in controlled

release systems. However, there are limited to explore the potential of chitosan

nanoparticles as slow and control release for NPK fertilizers. This brings out the idea of

developing biodegradable fertilizer base chitosan as binder and hydrophilicty controller.

Over the last years, there has been research and increasing interest in the use of polymers

combining with starch as binder and coating material as a potential biodegradable

fertilizer. According to Liu et al. (2007), there is a research in improving properties of

fertilizer with controlled release and water retention by using chitosan-coated fertilizer

polyacrylic-co-acrylamide (P (AA-co-AM) with controlled release and water retention

which possessed three layer structure of fertilizer. Therefore, although the control release

property has been improved, but after the coating layer is dissolved, the nutrient fertilizer

2

in its core will degrade. Hence, due to increase in water absorbency, the degradation of

fertilizer will become faster after the coated layer dissolve completely. According to

Riyajan et al. (2012), natural rubber (NR) has potential for controlling urea release. The

hydrophobic group of encapsulation of urea fertilizer by NR can control releasing

nutrient from capsule and easily degrade to soil. Epoxidized Natural Rubber (ENR) is

chemically modified from NR to improve hydrophilicity of NR. However, there is no

study in incorporated this ENR in urea fertilizer as control and slow release fertilizer.

In addition, formaldehyde is the material that gives reaction when the elevated level is

reached. The dangerous chemical will emit into the air. This can causes watery eyes,

nose irritations, wheezing and coughing, fatigue, skin rash, severe allergic reactions,

burning sensations in the eyes and throat, nausea, and difficulty in breathing in some

humans. In this research, formaldehyde is widely found use in agricultural technology as

non-biodegradable binder. Recently, due to many reports of formaldehyde affect to

health and environment there are only few studies focuses on the effect of formaldehyde

based on urea fertilizer in agriculture; especially in Malaysia. Controlled studies have

suggested that tolerance to formaldehydes odour and irritating effects can occur over a

prolonged exposure (Meriat et al., 2008). By replacing formaldehyde with biodegradable

and free chemical reaction is purposely suggested.

In this research, the incorporation of ENR in biodegradable chitosan based urea fertilizer

is hypothesized to impart the biodegradable properties to the ENR/chitosan based urea

fertilizer. The introduction of epoxirane ring with existing double bonds in the ENR will

act as hydrophobic contributor and chitosan as hydrophilic controller to accelerate the

degradation process at a certain time that accomplices with nutrient needed by plant. In

principle, the slow and control release with hydrophobicity properties could be

significantly improve. To increase the binding energy ENR and chitosan was

incorporated in the mixture. ENR is well known as an ideal material for biodegradable

type which important to increase the reaction between chitosan and urea. As a result, this

research is hoped can formulate and develop into new potential products besides it

capable reducing level of formaldehyde releasing to the environment.

3

1.3 Objective The aim of this research is to understand the specific cause and effect of formaldehyde

based urea fertilizer characteristics and able to understand the properties, structure and

effect of biodegradable urea fertilizer on water, soil and air. The objectives of this

research are:

i. To incorporate ENR in biodegradable chitosan based urea fertilizer

through wet mixing and compression molding.

ii. To study the effect of ENR loading on the physical, mechanical,

compositional, morphological and thermal properties of chitosan based

biodegradable urea fertilizer.

iii. To characterize the physical, mechanical, compositional, morphological,

and thermal properties of ENR/chitosan based urea fertilizer.

1.4 Scope

The scope of this research is to study the effect of ENR in biodegradable urea fertilizer

as hydrophobic contributor. ENR/chitosan based urea fertilizer is produced by wet

mixing followed by drying and compaction to desired shape where ENR loading is

varied in the formulation composition of urea fertilizer. Material testing is performed to

measure the physical and mechanical properties in term of density, water absorption,

water retention, biodegradability, hardness and compression. The properties of urea

fertilizer is further characterized by using morphological, thermal and compositional

analysis of the sample using scanning electron microscopy (SEM), differential scanning

calorimetry (DSC), x-ray diffraction (XRD), and fourier transform infrared

spectroscopy (FTIR).

4

1.5 Chapter Overview

The organization of this report is as follow; Chapter 1 provides the introduction of the

research background consist of problem statement, objectives, scopes of research and

report organization. Chapter 2 comprise of a literature review of previous research

finding on application of, chitosan, epoxidised natural rubber (ENR), slow and control

released fertilizer and many more in fertilizer and the preview of testing and analysis that

conducted in this research. Chapter 3 covers the methodology of the research including

flow chart, raw materials, sample preparation, testing, analysis and Gantt chart where as

Chapter 4 presents the comprehensive discussion on the results obtained throughout the

study. Conclusion and recommendation experimental of this study is presented in

Chapter 5.

5

2.1 Fertilizer

Fertilizer is a chemical compound containing three elements which are nitrogen (N),

phosphorus (P) and potassium (K). It is added to soil to release nutrients which are

essential for growth and development of crops. There are various type of fertilizer either

organic or inorganic fertilizers (Papangkorn et al., 2008). Cardarelli (2000) has stated

that fertilizers are natural or synthetic chemical compound chemical compounds

containing nutrients essential for the normal growth and development of plants. As a

general rule, all carbon (C) and oxygen (O) necessary to the plants are provided, via

photosynthesis, from carbon dioxide and oxygen gases from the atmosphere while rain

and ground waters supply all the hydrogen (H) required. All other nutrients which are N,

P and K must be transformed from minerals and organic matter, by microorganisms

respectively, before becoming available for plants. The most important fertilizers are

fertilizer product which also is called as chemical or mineral fertilizers, manures and

plant residues. A fertilizer product is a material produced by industrial processes with

the specific purpose of being used as a fertilizer. Fertilizers are essential in today’s

agricultural system to replace the elements extracted from the soil in the form of food

and other agricultural products (Rutland et al., 1998).

In practice, either industrial minerals or chemicals are currently used as feedstock’s for

manufacturing fertilizers and hence it is necessary to distinguish two groups which are

mineral fertilizers and chemical fertilizers. Mineral fertilizers that consist mainly of

LITERATURE REVIEW

CHAPTER 2

6

natural or manufactured industrial minerals such as saltpetre, potash, and phosphate rock

meanwhile chemical fertilizers that are chemical commodities, such as ammonia and

urea, produced as products or by-product by the chemical industry (Cardarelli, 2000).

The N-P-K descriptions are presented in Table 2.1.

Table 2.1: N-P-K description (Materials Handbook: A Concise Desktop Reference, 2000)

Nutrients Description

Nitrogen (N)

Plant intake nitrogen compound are converted into proteins by complex

biochemical reaction. For improving the nitrogen intake of crops, nitrogen rich

feed stocks must be added to soils artificially. Today, the major industrial

minerals used as nitrogen rich feedstock such as, saltpetre (KNO3), soda nitre

(NaNO3), urea (NH2CONH2), urea formaldehyde (NH2CONHCH2OH) and

many more. Important because it promotes vigorous plant growth, increases

top growth, and is a building block for protein.

Phosphorus (P)

The least used major nutrients. The role of phosphorus in cell of plant is to

provide chemical energy which is stored within the strong phosphorus

chemical bond. The behaviour of phosphorus is unique in soils as it is usually

bound to clay minerals and does not move downward with percolating ground

waters and hence accumulates in the top soil. The major phosphorus rich

materials are synthetic chemicals obtain from chemical treatment of phosphate

rock that is mainly apatite by concentrated sulphuric acid. Promotes cell

division and stimulates healthy root growth and is essential for seed

germination.

Potassium (K)

It is indispensable as a nutrient and it is required in large quantities by most

plants. The role of potassium in plants is regulatory and catalytic. Growing

plants absorb potassium as potassium cations K+ but the metabolic route is

unclear. The major industrial mineral used as potassium feedstock is sylvinite

(KCl) also known as muriate of potash. Potash is an essential nutrient for

photosynthesis which also promotes fruit formation and imparts disease

resistance and winter hardiness.

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