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/CaCO3, PP/CNSP and 50/50 PP/CaCO3, 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 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 Polyethylenterephthalat

PIB Polyisobutylene

PMMA Polymethylmethacrylate

PP Polypropylene

PPC Polypropylene copolymer

PRPCs Particle reinforced plastics composites

PS Polystyrene

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 appreciably.

  • 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.

  • 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 carry out mechanical tests such as hardness, tensile strength, elongation at break, impact resistance and to carry out sorption test on the produced samples,
  4. Determination of microstructure of the processed samples using scanning electron microscopy (SEM).
  • Justification

Cashew nut shell powder as one of the fillers used in this research can reduce the cost of production of articles compared to the commercially available fillers. It can create job opportunity locally, by paying people supplying it for the researchers. The use of cashew nutshell powder as filler can help to reduce environmental pollution caused by the shell, this is because, it is biodegradable and it can decay and becomes a pollutant to the society.

  • Scope of the study
  1. To prepare and characterise CNSP filler
  2. To fill cashew nutshell powder in polypropylene
  3. To fill calcium carbonate in polypropylene
  4. To carry out mechanical tests on the prepared composite, such as hardness, tensile strength, elongation at break, sorption test, and impact resistance
  5. To compare the impact resistance of cashew nutshell powder and calcium carbonate filled polypropylene

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