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TITLE
DEDICATION
CERTIFICATE-1
CERTIFICATE-2
CERTIFICATE 3
DECLARATION
ACKNOWLEDGEMENT
List of Abbreviations
CONTENTS
1. Introduction
1.1. Methods of vulcanization
1.1.1. Peroxide vulcanization
Table1.1. Advantages and disadvantages of peroxide crosslinking [ 5 ]
1.1.2. Resin cross linking
Table 1.2. Recipe for vulcanization by resins
1.1.3. Silane cross linking
1.1.4. Metal oxide cross linking
Table 1.3. Metal oxide systems for chloroprene rubber
1.1.5. Radiation induced cross linking
1.1.6. High temperature cross linking
1.1.7. Dynamic vulcanization
1.1.8. Sulphur vulcanization
1.2. Unaccelerated sulphur vulcanzation
1.3. Accelerators
Table1.4. Principal classes of accelerators used in the sulphur vulcanisation of elastomers
1.4. Accelerated sulphur vulcanization
Fig.1.2 Typical cure curve with different accelerator systems
Fig.1.3. Typical rheograph showing different stages on curing
Fig.1.4. Rheograph showing different behavior in modulus development
Table 1.5. Composition of conventional, semi EV and EV cure systems [88]
Fig.1.5. Features of NR vulcanizate produced by an efficient crosslinking system
1.5. Role of activators
Table 1.7. Intluence of degree of crosshkmg on Physical Properties
1.6. Sulphur donor systenis
Fig.1.7. Complex formed in the presence of sulphur donors
1.7. Influence of fillers
1.8. Binary accelerator systems
Fig.1.8. Effect of binary accelerators in mechanical properties of vulcanizate
1.9. Concepts of double networks
1.10. Methods to characterize networks
1.11. Scope and objectives of the work
1.12. References
2. Materials and Experimental Methods
2.1 Materials
Table 2.1. Characteristics of ISNR-5
Table 2.2. Properties of Synaprene (SBR- i 502)
2.2 Synthesis of 1-phenyl-2, 4-dithiobiuret (DTB)
2.3 Characterization of DTB
2.3.1. IR Spectrum
2.3.2. H-NMR Spectrum
2.3.3. Mass Spectrum
2.4. Compounding o rubber
2.5. Cure characteristics
Fig. 2.4. A typical rheograph obtained from Monsanto Rheometer (R-100)
2.6. Vulcanization
2.7. Preparation of double networks
2.8. Mechanical properties
2.8.1. Tensile strength, modulus and elongation at break
2.8.2. Tear resistance
2.8.3. Compression set
2.8.4. Rebound resilience
2.8.5. Hardness
2.8.6. Ageing
2.9. Network characterization
2.9.1. Determination of total cross link density
2.9.2. Determination of mono, di and polysulphidic linkages.
2.10. Dynamic mechanical thermal analysis (DMTA)
2.11. Scanning electron microscopy
2.12. References
3. Influence of DCBS / DTB Binary Accelerator System in Vulcanization of Natural Rubber
3.1. Introduction
3.2. Results and discussion
3.2.1. Processing characteristics
Table 3.1. Cure Charactenstics of Mixes Cured at 150°C (EV)
3.2.2. Kinetic studies
Fig.33. Kinetic plots of curing of NR using DCBS/DTB (EV)
Fig.3.4. Kinetic plots of curing of NR using DCBS/DTB (CV)
Fig.3.5. Arrhenius plots for curing of NR using DTBS/DTB system (EV)
Table 3.3. Cure Kinetics & Energy of Activation of Mixes (EV)
3.2.3. Mechanical properties
Table 3.5. Mechanical Properties of NR Cured Using DCBS/DTB (EV)
Fig.3.7. Stress-strain curves for DCBS/DTB cured NR vulcanizates (EV)
3.2.4. Cross link density measurements
Table 3.7. Network Characterisation of NR Vulcanizates Cured UsingDCBS/DTB (EV)
Table 3.8 Network Characterisation of NR Vulcanizates Cured UsingDCBS/DTB
3.2.5. Thermal ageing
3.2.6. Viscoelastic properties
3.2.7. Effect of fillers
3.2.8. SEM studies
Fig.3.15. SEM picture showing carbon black dispersion in DCBS/DTB cured NR vulcanizates (a) 40phr (b) 50phr (c) 60phr (d) 70phr.
3.3. References
4. Effect of TBBS / DTB Binary Accelerator System on Natural Rubber Vulcanization
4.1. Introduction
4.2. Results and discussion
4.2.1. Cure characteristics
Fig.4.2.Rheograph of the TBBS/DTB mixes (CV)
Table 4.2. Cure Characteristis of the Mixes Cured Using TBBS/DTB (CV)
4.2.2. Cure kinetics
4.2.3. Mechanical properties
4.2.4. Chemical characterization
4.2.5. Ageing behavior
4.2.6. Viscoelastic properties
4.2.7. Effect of Fillers
4.3. References
5. Influence of DTB / MBS Binary Accelerator System of Natural Rubber Vulcanization
5.1. Introduction
5.2. Results and discussion
5.2.1. Cure Characteristics
Table 5.2. Cure Characteristics of the MBS/DTB Cured Natural Rubber (CV)
5.2.2. Kinetic studies
Table 5.3. Cure Kinetics and Activation Energy of the Mixes (EV)
Fig.5.3. Kinetic plots of NR stocks cured using MBS/DTB [EV]
5. 2. 3. Mechanical properties
Fig.5.5. Stress-strain curves of MBBS/DTB cured NR vulcanizates (EV)
5.2.4. Ageing studies
5.2.5. Network characteristics
Table 5.7. Network Chxacteristics MBSDTB Cured NR Vulcanizates (EV)
5.2.6. Viscoelastic measurements
Fig.510. Variation of loss modulus with temperature for MBS/DTB cured vulcanizates.
5. 2.7. Influence of fillers
5.3. Comparative evaluation of the effect of DTB / Sulphenamide binary accelerator systems
5.4. References
6. Influence of DTB as a Binary Accelerator in Styrene- Butadiene Rubber
6.1. Introduction
6.2. Results and discussion
6.2.1 Cure characteristics
6.2.2 Kinetic studies
Table 6.1. Composition of SBR Mixes.
Table 6.2. Cure Characteristics of Gum SBR Vulcanizates Cured using DTB as a Binary Accelerator
Table 6.3. Kinetic Studies of DTB Cured SBR Vulcanizates
6.2.3 Mechanical properties
6.2.4 Ageing studies.
6.2.5 Cross link density measurements
6.2.6. Dynamic Mechanical Properties
6.2.7 Effect of fillers
6.3. References
7. Studies on New Binary Accelerator Systems on Technical Properties of NR / SBR blends
7.l. Introduction
7.2. Results and discussion
7.2.l. Cure characteristics
Fig.7.1. Rheograph of NR/SBR stocks cured with DCBS/DTB [EV]
7.2.2. Kinetic studies
Table 7.3. Kinetic Studies of DTB cured NR/SBR Blends (EV)
Table 7.4. Kinetic Studies of DTB cured NR/SBR Blends (CV)
7.2.3. Mechanical properties
Table 7.5. Mechanical Properties of DTB Cured NR/SBR Vulcanizates (EV)
7.2.4. Network characterization
7.2.5 /iscoelastic properties
7.3. References
8. Studies on Double Networks Prepared Using Different Binary Accelerator Systems -.
8.1. Introduction
8.2. Experimental
8.2.1. Double network formation
8.2.2. Mechanical properties
8.2.3. Swelling studies
8.3. Results hind discussion
8.3.1. Swelling studies
8.3.2. Cross link density
8.3.3 Ageing studies
Fig. 8.8. Effect of thermal ageing on double networked samples cured with MBS
8.3.4. Dynamic mechanical properties
8.4. References
9. Conclusion and Future Outlook
Future Outlook
APPENDICES