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Thesis Details
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TITLE
DEDICATION
CERTIFICATE
DECLARATION
ACKNOWLEDGEMENT
CONTENTS
GLOSSARY OF TERMS
1. Introduction
1.1. Thermoplastic elastomers (TPFs)
1.2. Incompatible blends.
Fig.1.1 (a) Interface between immiscible polymers and (b) Interfacial density profile between immiscible polymers
Fig.1.2 Phase arrangements in heterogeneous blends during extrusion: (a) side by side (b) sheath core and (c) matrix fibril.
1.3. Compatibilisation concepts.
Table 1.1. Polymex blends compatibillsed by different techniques [lo].
1.4. Copolymers as compatibilisers.
1.5. Theoretical aspects of compatibilisation.
1.6. Compatibilisation of thermoplastic elastomers.
1.7. Scope of the work.
1.8. Objectives.
1.8.1. Miscibility and phase separation behaviour in solution
1.8.2. Effect of graft copolymer concentration on solid state morphology.
1.8.3. Rheological properties.
1.8.4. Mechanical properties.
1.8.5. Thermal properties.
References.
2. Experimental Techniques
2.1. Materials.
2.1.1. Natural rubber (NR)
2.1.2. Poly (methyl methacrylate) (PMMA)
2.1.3. Graft copolymer (NR-g-PMMA)
Table 2.1. Characteristics of the polymers.
2.1.4. Solvents.
2.1.5. Chemicals.
2.2 Preparation of the blends.
2.2.1. Solution cast blends.
2.2.2. Melt mixed blends.
2.3. Morphology of the blends.
2.4. Viscosity measurements.
2.5. Phase separation experiments.
2.6. Mechanical properties.
2.6.1. Tensile strength.
2.6.2. Tear strength.
2.6.3. Izod impact strength.
2.6.4. Morphology of the failure surface.
2.7. Rheological properties.
2.7.1. Measurements.
2.7.2. Extrudate swell.
2.7.3. Melt flow indices.
2.7.4. Morphology of the extrudate.
2.8. Thermal analysis.
2.8.1. Dynamic mechanical analysis.
2.8.2. Differential scanning calorimetry.
2.8.3. Thermogravimetry (TG)
References.
3. Miscibility, Phase Separation and Compatibilisation Effects in Solution
3.1. Miscibility studies by viscometry.
Table 3.1 Experimental and calculated values of [q] for NWPMMAblends.
Fig.3.4. Experimental and calculated inhinsic viscosities (111 of WMMApolymer blends.
3.2. Heat of mixing and compatibility.
Fig.3.7. Heat of mixing (AH) versus weight percentage of PMMA in the blend.
3.3. Polymer / polymer and polymer blend / solvent interactions.
Table 3.2. Interaction parameters for polymer-polymer system.
Table 3.3. Interaction parameters for polymer blend-solvent system (toluene)
3.4. Phase separation behaviour.
3.4.1. Effect of graft copolymer concentration.
3.4.2. Effect of nature of solvent on phase separation.
3.4.3. Effect of mode of addition on phase separation.
3.4.4. Effect of graft copolymer / homopolymer molecular weight on phase separation.
References.
4. Compatibilising Effect of Graft Copolymers on the Solid State Morphology
4.1. Effect of graft copolymer concentration on morphology.
Fig.4.1. Optical photornicrographs of 50/50 NR/PMMA blend with and without graft copolymer (a) 0 % graft and (b] 15% graft.
Fig.4.2. Scanning electron micrographs of 50/50 NR/PMMA blends: (a) 0% graft. (b) 5% graft, (c) 10% graft and (d) 15% graft.
Fig.4.3. Effect of graft copolymer concentration on the domain size of thedispersed phase of different NR/PMMA blends.
Fig.4.4. Effect of graft copolymer concentration on interparticle distance of the dispersed phase in 50/50 NR/PMMA blend.
4.2. Effect of homopolymer molecular weight on morphology.
4.3. Effect of graft copolymer on particle size distribution.
Fig.4.5 Influence of molecular weight of NR on morphology.
Fig.4.6 Effect of molecular weight of natural rubber on CMC
Fig.4.7. Effect of copolymer concentration on domain size distribution 50/50 NR/PMMA blend.
4.4. Effect of casting solvents on morphology.
4.5. Effect of mode of addition of graft copolymer on morphology.
Fig.4.8. Speculative model representing the behaviour of copolymer having different mode of mixing.
4.6 Discussion.
Fig.4.9 Effect of graft copolymer volume fraction on particle size reduction.
Table 4.1. Dispersed phase diameter (2R) at CMC and a values of the system.
References.
5. Melt Rheological Properties
5.1. Effect of blend ratio and shear stress on viscosity.
Fig.5.2. Variation of shear viscosity with weight percentage of NR in W M M Asolution cast blends at different shear rates.
Fig.5.3. Speculative model illustrating the structure development of PMMA domains at a shear rate of (a) 33.3 s-1and (b) 833.3 s-1
Fig.5.4. Experiment and theoretical values of shear viscosity as a function of weight per cent of NR at a shear rate of 333 S-1
5.2. Effect of compatibiliser and shear stress on viscosity of 50/50 NR / PMMA blends.
Fig.5.7. Scanning electron micrographs of extrudate morphology as a function of graft copolymer concentration of 50/50 NR/PMMA solution cast blends: [a) 0%. (b) 5% and (c) 10% graft copolymer.
Fig.5.8. Variation of average domain size as a function of graft copolymer concentration in 50/50 NR/PMMA solution cast blends.
Fig.5.9. Variation of interparticle distance as a function of graft copolymer concentration in 50/50 NR/ PMMA solution cast blends.
Fig.5.10. Relationship between average diameters and shear viscosity as a function of graft copolymer concentration at a shear rate of 33 s-1
5.3. Comparison between melt and solution mixed blends.
Fig.5.11. Variation of shear viscosity with shear stress of 0/100, 50/50, 70/30 and 100/0 NR/PMMA melt mixed blends.
Fig.5.12. Variation of shear viscosity with weight percentage of NR in NR/PMMA melt mixed blends at different shear rates.
Fig.5.13. Variation of shear viscosity with shear stress of 50/50 NR/PMMA melt mixed blends with 0, 2, 5 and 10% graft copolymer and dicurnyl peroxide vulcanised systems.
Fig.5.14. Variation of shear viscosity as a function of graft copolymer concentration of 50/50 NR/PMMA melt mixed blends at different shear rates.
5.4. Effect of temperature on melt viscosity.
Fig.5.15. Effect of temperature dependence on the melt viscosity of 50/50 NR/PMMA melt mixed blends with 0, 5 and 10% graft copolymer concentration
Fig. 5.16. Arrhenius plot. for NR/PMMA melt mixed blends with 0, 5 and 10% graft copolymer concentration.
Table 5.1. Activation energy for 50/50 NR/PMMA melt mixed blends.
5.5. Shear rate temperature super position curve.
Fig.5.17. Flow curve of shear stress versus log shear rate at 130, 140 and 150°C.
Fig. 5.18. Master curve of modified shear stress versus log shear rate as a function of temperature.
Fig.5.19. Variation of shift factor as a function of reciprocal temperature
5.6. Flow behaviour index.
Table 5.2. Effect of % of NR on flow behaviour index at 130 0C.
Table 5.3. Flow behaviour index of 50/50 NR/PMMA blend as a function of temperature and copolymer loading.
5.7. Deformation of the extrudate.
Fig.5.20. Extrudate deformation at different shear rates of NR/PMMA blends as a function of blend ratio and compatibiliser loading.
5.8. Melt elasticity.
5.8.1. Die swell.
Table 5.4. Die swell, principal normal stress, recoverable elastic shear strain and shear modulus values of 50/50 NR/PMMA at 333 s-1.
5.8.2. Principal normal stress differences.
5.8.3. Recoverable elastic shear strain (SR)
Fig.5.21. Principal normal stress difference with shear rates as a function of graft copolymer concentration.
5.8.4. Elastic shear modulus (G)
5.9. Melt flow indices.
5.9.1. Melt flow index and rheometer data.
Table 5.5. MFI values of NR/PMMA solution cast blends.
Fig.5.22. Master curve of modified shear viscosity versus modified shear rates as a fundion of graft copolymer concentration at 130°C.
5.10. Influence of processing history on morphology and stability of the blend.
Fig.5.23. Scanning electron rnicrogmphs of extndate of 50/50 NR?PMMA blends:
References.
6. Mechanical Properties
6.1. Effect of blend ratio on morphology and mechanical properties.
6.1.1. Morphology of the blend.
6.1.2. Mechanical properties.
Fig.6.1. Scanning electron rnicrographs of NR/PMM blends: (a) 70/30 (b) 50/50 and (c) 30/70.
Fig.6.2. Effect of blend composition on the domain size distribution of 70/30 and50/50 NR/PMMA blends.
Fig.6.3 Stress-strain curves of NR/PMMA blends as a function of composition.
Table 6.1. Mechanical properties of NR/PMMA blends.
Fig.6.4. Effect of weight percentage of NR on tensile and tear strength of NR/PMMA blends.
Fig. 6.5. Effect of weight percentage of NR on elongation at break and Youngsmodulus of NR/PMMA blends.
6.1.3. Model fitting.
Fig.6.6. Experimental and theoretical values of tensile strength as a function of volume fraction of NR.
Fig.6.7. Experimental and theoretical values of tear strength as a function of volume fraction of NR.
6.2. Effect of graft copolymer on mechanical properties.
6.2.1. Tensile properties.
Fig.6.8. Stress-strain curves of 50/50 NR/PMMA solution cast blends as a function of graft copolymer concentration.
Fig.6.9. Stress-strain curves of 50/50 NR/PMMA melt mixed blends as a function of graft copolymer concentration.
Table 6.2. Mechanical properties of 50/50 NR/PMMA blends with graft copolymer.
Fig.6.10. Variation of tensile strength and average domain size as a function of graft copolymer concentmtion of 50/50 NR/PMMA blends.
6.2.2. Tear properties.
6.2.3. Izod impact strength.
Fig.6.11 Variation of tear strength as a function of graft copolymer concentration on 50/50 NR/PMMA blends cbtained by solution and melt mixing techniques.
Fig.6.12 Variation of izod impact strength as a function of graft copolymer concentration on 50/50 NR/PMMA blends obtained by solution and melt mixing techniques.
6.3. Comparison of mechanical properties between melt mixed and solution cast blends.
Fig.6.13. Variation of tensile strength as a function of graft copolymer concentration on 50/50 NR/PMMA blends obtained by solution and melt mixing techniques.
6.4. Failure topography.
Fig. 6.14. Tensile fractographs of 50/50 NR/PMMA blends: (a) 0%. (b) 5%, (c) 10% and (d) 15% graft copolymer.
Fig.6.15. Tear fractographs of 50/50 NR/PMMA blends: (aj 0%. (b) 5% and (c) 10% graft copolymer.
References.
7. Thermal Characteristics
7.1. Dynamic mechanical properties.
7.2. Differential scanning calorimetry.
7.3. Thermogravimetry.
References.
8. Conclusion and Scope of Future Work
8.1. Conclusion.
8.2. Scope of future work.
8.2.1. Measurement of interfacial tension.
8.22. Interfacial thickness.
8.2.3. Location of the copolymer.
8.2.4. Comparison with block copolymer.
8.2.5. Fabrication of various products.
APPENDICES
APPENDIX I List of Publications in International Journals
APPENDIX II Papers Presented at NationaVlnternationaI Conferences
Curriculum Vitae