STUDIES ON THE IMPACT RESISTANCE OF CASHEW NUTSHELL POWDER AND CALCIUM CARBONATE FILLED POLYPROPYLENE

ABSTRACT

Mechanical and morphological properties of pure polypropylene (PP) polypropylene/calcium carbonate (PP/CaCO₃) and polypropylene/cashew nutshell powder (PP/CNSP)are reported in this work. The composites were prepared by compression moulding technique. The compressed moulded articles that is the PP, (PP/CaCO₃) and (PP/CNSP) of different compositions (10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/20) were characterised for mechanical properties, water absorption capacity, structural characterisation and morphological arrangements. Comparative studies was made on the mechanical properties of the pure polypropylene (PP), polypropylene/calcium carbonate (PP/CaCO₃) and polypropylene/cashew nutshell powder (PP/CNSP). Mechanical properties such as tensile strength, Young‟s modulus and percentage elongation at break, Hardness behaviour and Impact resistance of both PP/CaCO₃ and PP/CNSP composites increased with increment of filler weight content (10-50g). It was noted that the specimen samples of ratio50_/40 PP/CaCO₃ and PP/CNSP had the highest tensile strength, when compared with other sample. These specimens could bear loads of 1075N and 468N with extensions of 4.44mm and 6.12mm respectively. Decrease in the mechanical properties were noted on continuous addition of both fillers, with drastic reduction of the mechanical properties at (70g and 80g) fillers weight except hardness that slightly increased at all the filler loading (10-80g). The surface sorption characteristics of calcium carbonate and cashew nutshell powder have been investigated and the highest percentage was recorded at 20/80 of PP/CNSP (100%). Scanning electron microscopy (SEM) revealed that, both 60/40 PP/CaCO_3, PP/CNSP and 50/50 PP/CaCO_3, PP/CNSP are completely compatible at which there are no phases that are grossly separated. X-ray diffraction analysis showed that, the incorporation of the two fillers into the neat polypropylene decreased the crystallinity of the polypropylene and the crystallinity decreases with increasing filler‟s loading.

TABLE OF CONTENT

TITLE PAGE

ABSTRACT

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

1.2       Research problem

1.3       Aim and objectives

1.4       Justification

1.5       Scope of the study

CHAPTER TWO

2.0       LITERATURE REVIEW

2.1       Background of Literature

2.2 Components of Composite Material

2.2.1 Matrix

2.2.1.1Polypropylene

2.2.2    Polymerization

2.2.3    Properties

2.2.4    Applications

2.3       Reinforcements functions on polymer composite

2.3.1    Classification and types of fillers

2.3.2    Types of fillers

2.3.3 Physical properties, uses and health effects

2.3.4 Environmental impact

2.3.5 Classification of CaCO3

2.3.6 Uses of CaCO3 as filler

2.3.7    Cashew tree

2.3.8    Distribution

2.3.9    Constituents cashew

2.3.10 Polymers and polymer composites

2.3.11 Polymer composites modification

2.3.12 Types and components of polymer composites

2.3.13 Parameters affecting properties of composites

2.3.14 Applications, trends, and challenges of fillers

2.3.15 Compounding and mixing processes

2.4.1    Plasticizers

2.4.2 Stabilizers

2.4.3 Colourants

2.4.4 Flame retardants

2.5 Thermoplastics processing techniques

2.5.1    Extrusion

2.5.2    Types of extrusion

2.5.3    Moulding

2.5.4    Compression moulding

2.5.5    Injection moulding

2.5.6    Blow moulding

2.5.7    Reaction-injection moulding (RIM)

2.5.8    Rotational moulding

2.5.9    Calendaring

2.6.1    Mechanical properties of plastics

2.6.2    Hardness

2.6.3    Abrasion resistance

2.6.4    Compression set and flex fatigue resistance

2.6.5    Flex fatigue resistance

2.6.6    Tensile strength, elongation at break and modulus

2.6.7    Resilience

2.7       Morphological Characterisation of Composites

2.7.1    Spectroscopic tests

2.7.2    Microscopic techniques

2.7.3    Thermodynamic methods

2.7.4    X-ray diffraction (XRD)

2.7.5    Basics of crystallography

2.7.6    Production of X-rays

2.7.7    Bragg’s law and diffraction

2.7.8    Applications of XRD

2.7.9    Scanning electron microscopy (SEM)

2.7.10 Thermoforming/solid phase forming

2.8       Physical Method of Characterising Composites

CHAPTER THREE

3.0       MATERIALS AND METHODS

3.1       Materials

3.2       Apparatus Used

3.3       Equipment Used and their Sources

3.4       Preparation of Sample

3.4.1    Filler Preparation

3.4.2    Mixing of the Compound

3.5       Determination of Mechanical Properties of the Prepared Polypropylene Composites

3.5.1 Determination of Tensile strength

3.5.2 Determination of Hardness of the prepared composites

3.5.5 Determination of Impact Strength of the prepared samples

3.5.6 Determination of microstructure of the prepared composites byScanning Electron Microscopy

3.5.7 Determination of the crystallinity of the prepared composites by X-ray Diffraction

3.5.8 Determination of water absorption behaviour of composites

CHAPTER FOUR

4.0 RESULTS

4.1 Result of Tensile Strength

4.2 Effect of Filler Loading on the Stress of the Composites Prepared

4.2 Result of Elongation at break

4.4 Result of Young’s Modulus

4.5 Impact strength results

4.6 Hardness Results

4.7 Sorption Result

4.7 Morphology Results

CHAPTER FIVE

5.0 DISCUSSION OF RESULTS

5.1 Structural Characterisation of Cashew Nutshell Powder

5.2 Tensile Strength

5.3 The impact strength

5.4 Hardness

5.5 Statistical Analysis of Impact Strength

5.6 Effects of modification of unfilled and filled PP, PP/CaCO3 and PP/CNSP Composites on equilibrium sorption

5.6.4 Morphological studies on the PP, PP/CaCO3 and PP/CNSP composites

5.6.5 Structural Characterisation of the Polypropylene Composites prepared

CHAPTER SIX

SUMMARY, CONCLUSION AND RECOMMENDATIONS

6.1 Summary of Results

6.3 Conclusion

6.3 Recommendations

REFERENCES:

APPENDIX

LIST OF ABBREVIATIONS

ABS                                                    Acrylonitrile-butadiene-styrene

AFM                                                    Atomic Force Microscope

ASTM                                                  American Society for Testing Materials

CaCO₃                                                Calcium Carbonate

CNSP                                                  Cashew Nutshell Powder

CRH                                                    Chopped Rice Husk

EVA                                                    Ethylene vinyl acetate

HDT                                                     Heat Distortion Temperature

HPP                                                      homogeneous polypropylene

IM                                                         Initial modulus

LDPE                                                  Low density polyethylene

LLDPE                                               Linear low density polyethylene

LOE                                                     Linseed Oil Epoxide

NR                                                        Natural Rubber

OM                                                       Optical Microscope

PE                                                         Polyethylene

PEMA                                                 Poly (ethyl methacrylate)

PET                                                      Polyethyleneteraphthalate

PIB                                                       Polyisobuthylene

PMMA                                               Polymethamethylacrylate

PP                                                  Polypropylene

PPC                                                      Polypropylene copolymer

PRPCs                                               Particle reinforced plastics composites

PS                                                          Polystyrine

PVAc                                                  Polyvinyl acetate

PVC                                                     Polyvinylchloride

SALS                                                  Small angle light scattering

SAXD                                                 Small-Angle X-ray diffraction

SAXS                                                  Small-Angle X-ray Scattering

SD                                                         Spinodal decomposition

SEM                                                     Scanning Electron Microscopy

TS                                                          Tensile strength

UTM                                                    Universal Testing Machine

WAXD                                               Wide Angle X-ray Diffraction

CHAPTER ONE

INTRODUCTION

1.1 Background of the Study

Particle reinforced plastics composites (PRPCs) are composites to which fillers (discrete particles) have been added to modify or improve the properties of the matrix and/or replace some of the matrix volume with a less expensive material. Common applications of PRPCs include structural materials in construction, packaging, automobile tires, medicine, etc. Determination of effective properties of composites is an essential problem in many engineering applications (Van, 2003 and Love, 2004).

These properties are influenced by the size, shape, properties and spatial distributions of the reinforcement (Liu, 1995 and Lee, 1998).

Modification of organic polymers through incorporation of additives yield, with few exceptions, multiphase systems containing the additive embedded in a continuous polymeric matrix. The resulting mixtures are characterised by unique microstructures that are responsible for their properties. Polymer composites are mixtures of polymers with inorganic or organic additives having certain geometries. Thus, they consist of two or more components and two or more phases. In addition to polymer composites, other important types of modified polymer systems include polymer-polymer blends and polymeric forms. Blending procedures had been employed since time immemorial. The principle of blending is geared towards achieving property averaging. A blend is therefore the physical mixture of two or more substances, without a chemical bond, (Mamza, 2011).

Among the various studies carried out with particle filled PP worth mentioning, are works by Maiti and Mahapatro (1992 and 2011) on the tensile and impact behaviour of nickel powder-filled PP and CaCO₃ filled PP composites. It was discovered that the addition of nickel-powder causes decrease in tensile modulus, tensile strength and elongation-at-break with increasing filler. In the case of the addition of CaCO₃, tensile modulus increased while tensile strength and elongation-at-break decreased with increasing filler. Izod impact strength for the composites at first application of filler loading increased up to a critical filler content, beyond which the value decreased inappreciably.

1.2              Research problem

The filler cashew nutshell powder (CNSP) has been under utilised, in composite formulation, as it is considered as waste material especially in the Northern part of Nigeria. Thus, there is need to convert this waste to wealth meanwhile this conversion would serve as an environmental waste control.

1.3                Aim and objectives

The main aim of this work was to determine the impact resistance of cashew nutshell powder and calcium carbonate used as fillers for polypropylene.

The specific objectives of the study are;

1.      Collection of samples from the outlet centre and preparation of samples.

2.      Determination and characterisation of cashew nutshell powder using X-ray diffraction analysis.

3.      To carryout mechanical tests such as hardness, tensile strength, elongation at break, impact resistance and to carry out sorption test on the produced samples,