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  • TITLE
  • DEDICATION
  • CERTIFICATE
  • DECLARATION
  • ACKNOWLEDGEMENT
  • PREFACE
  • GLOSSARY OF TERMS
  • CONTENTS
  • I. NTRODUCTION
  • I.1. Advantages of short fibres in comparison to cord reinforcement
  • I.2. Comparison with fibre reinforced plastics
  • I.3. Component materials
  • I. 3.1 Types of fibre reinforcement
  • I. 3.2 Elastomer types
  • I.4. Bonding systems
  • I.5. Effects of rubber compounding ingredients
  • I.6. Mechanism of adhesion
  • I.7. Preparation of composites
  • I.8. Fibre dispersion
  • I.9. Fibre breakage
  • I.10. Processing characteristics
  • I.11. Fibre orientation
  • I. 11.1 Effect on flow behaviour
  • 1.11.2 Effect of different processing techniques
  • I.12. Fibre orientation and Fibre distribution
  • I.13. Application of fibre. orientation
  • I.14. Critical fibre length
  • I.15. Design properties
  • I.16. Tensile strength
  • I.17. Tear strength
  • I.18. Fatigue and hysteresis properties
  • I.19. Creep
  • I.20. Modulus and elongation at break
  • I.21. Applications
  • I.21.1. v-belts
  • I.21.2. Hoses
  • I.21.3. Tyres
  • I.21.4. Other applications
  • I.22. Scope of the work
  • References
  • Table 1.1. Severity of breakage of different fibres
  • II. MATERIALS AND EXPERIMENTAL
  • II.l. Materials used
  • II.1.1. Natural rubber
  • II.1.2. Sisal fibre
  • II.1.3. Rubber chemicals
  • II.1.4. Other chemicals
  • II.1.5. Special chemicals
  • II.1.6. Solvents
  • II.2. Chemical treatment of fibre
  • II.3. Preparation of compounds
  • II.3.1. Composite preparation
  • II.3.2. Time of optimum cure
  • II.3.3. Moulding of test samples
  • II.3.4. Fibre breakage
  • II.4. Physical tests
  • II.4.1. Modulus, tensile strength and elongation at break
  • II.4.2. Tear resistance
  • II.4.3. Hardness
  • II.4.4. Abrasion resistance
  • II.4-5. compression set
  • II.4.6. Rebound resilience
  • II.5. Melt flow studies
  • II.5.1 Equipment details
  • II.5.2. Test procedure
  • II.5.3. Extrudate swell
  • II.6. Degradation studies
  • II.6.1. Ozone cracking
  • II.6.2. Radiation studies
  • II.6.3. Thermal ageing
  • II.7. Scanning electron microscopy studies
  • II.8. Dynamic mechanical properties
  • II.9. Stress relaxation
  • II.10. Swelling studies
  • References
  • Fig. II.I Determination of optimum cure time by modified tangent method.
  • Fig. II.2. Longitudinal and transverse orientation of the fibre.
  • III. MECHANICAL PROPERTIES OF SHORT SISAL FIBRE- NATURAL RUBBER COMPOSITES
  • III.1. Cure time
  • III.2. Effect of critical fibre length
  • III.3. Effect of chemical treatment
  • III.4. Effect of bonding agent
  • III.5. Effect of silica
  • III.6. Effect of fibre content
  • References
  • Fig.III.1a. SEM photomicrograph of the surface of theraw sisal fibre. 1b. SEM photomicrograph of the surface of acetylated sisal fibre.acetylated sisal fibre.
  • Fig.III.1c. SEM photomicrograph of tensile fracture surface of mix R showing good adhesion. Id. SEM photomicrograph of the surface of acetylated sisal fibre stripped out from mix E during tensile testing.
  • Fig.III.3c. SEM photomicrograph of the tear fracture surface of mix Q showing longitudinal fibre orientation. 3d. SEM photomicrograph of the. tear fracture surface of mix Q showing transverse fibre orientation.
  • Fig.III.8b. SEM photomicrograph of abraded surface ofmix S.8c. SEM photomicrograph of magnified abradedsurface of mix S.
  • IV. DYNAMIC MECHANICAL PROPERTIES OF SHORT SISAL FIBRE-NATURAL RUBBER COMPOSITES
  • IV.l. Effect of acetylation
  • IV.2. Effect of bonding agent
  • IV.3. Effect of fibre orientation
  • IV.4. Effect of fibre loading
  • References
  • Fig.IV.6a. SEM photomicrograph of the tensile fracture surface of mix B 6b. SEM photomicrograph of the tensile fracture surface of mix E
  • V. RHEOLOGICAL BEHAVIOUR OF SHORT SISAL FIBRE-NATURAL RUBBER COMPOSITES
  • V.1. Fibre breakage
  • V.2. Effect of shear rate on viscosity
  • V.3. Effect of temperature on viscosity
  • V.4. Flow behaviour index
  • V.5. Extrudate distortion
  • V.6. Melt elasticity
  • V.6.1. Die swell
  • References
  • Fig.V.3a. SEM photomicrograph of the cut surface of the extrudate of mix R at a shear rate of 3.33s 3b. SEM photomicrograph of the extrudate of mix R at a shear rate of 333.3s-1.
  • Fig.V.3.c SEM photomicrograph of the cut surface of the extrudate of mix U at a shear rate of 3.333s-1 3d. SEM photomicrograph of the cut surface of the extrudate of mix U at a shear rate of 333.3s-1
  • Fig.V.8- Optical photograph showing the effect of shear rate and fibre loading on the deformation of extrudates of mixes 0, P, Q, R, E, J, T and U.
  • VI. STRESS RELAXATION BEHAVIOUR OF SHORT SISAL FIBRE-NATURAL RUBBER COMPOSITES
  • VI.I. Fibre breakage
  • VI.2. Effect of strain level
  • VI.3. Effect of bonding agent
  • VI.4. Effect of fibre content
  • VI.5. Effect of ageing
  • VI.6. Effect of fibre orientation
  • References
  • VII. EQUILIBRIUM SWELLING BEHAVIOUR OF SHORT SISAL FIBRE-NATURAL RUBBER COMPOSITES
  • VII.I. Effect of bonding agent
  • VII.2. Effect of fibre loading
  • VII.3. Dimensional changes
  • VII.4. Effect of acetylation
  • References
  • Fig.VII.8. Optical photograph of the swollen samples in hexane.
  • Fig.VII.10. The optical photograph of the samples Lo and Q, at equilibrium swelling in hexane.
  • VIII. DEGRADATION BEHAVIOUR OF SHORT SISAL.FIBRE-NATURAL RUBBER COMPOSITES
  • VIII.I. Effect of radiation
  • VIII.2. Effect of thermal ageing
  • VIII.3. Effect of exposure to ozone
  • VIII.4. Effect of acetylation
  • References
  • Fig.VIII.8. Photograph of NR -sisal composites (with bonding agent) after exposure to ozone for40 h.
  • Fig.VIII.9. Photograph of NR-sisal composites (withoutbonding agent) after exposure to ozone for40 h.
  • Fig.VIII-10. Photograph of mixes Lo & Qo after exposure to ozone for 40 h.
  • SUMMARY AND CONCLUSIONS
  • APPENDIX I
  • List of publications from this work
  • APPENDIX II
  • Papers presented in national / international conferences from this work