Studies on the use of nano zinc oxide and modified silica in NR, CR ...

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Chapter 4 conventional ZnO compound show high torque values compared to compound with 2phr conventional ZnO. After evaluating the torque values, 2phr ZnO(p) and 2phr ZnO(s) and 5phr ZnO(c) are selected as the optimum dosage in filled and gum compounds. 80 Torque (dNm) 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 5 10 15 20 25 30 Time (min) Figure 4.1 Cure graph of natural rubber compounds NR-ZnO(c )5phr gum NR-ZnO(p) 2phr gum NR-ZnO(s) 2phr gum NR-ZnO(c )5phr filled NR-ZnO(p) 2phr filled NR-ZnO(s) 2phr filled NR-ZnO(p) 1phr filled NR-ZnO(s) 1phr filled Table 4.3 Cure behaviour of gum and filled compounds Property N-1 N-2 N-3 N-4 N-5 N-6 N-7 N-8 N-9 N-10 Scorch time (tS2),min Optimum cure time (t90), min Cure rate index (100/- t90-tS2) 5.22 5.74 5.63 4.33 2.54 2.56 2.59 2.44 2.44 1.78 7.89 7.79 7.68 7.27 4.94 4.48 4.46 5.46 5.06 4.84 37.45 48.78 48.78 34.01 41.66 52.08 53.47 33.11 38.16 32.67
Use of nano zinc oxide in natural rubber Cure behavior of gum and filled compounds are given in the Table 4.3 and figure 4.1. Comparing the cure characteristics of filled and gum compounds, compounds with 2phr ZnO(p) and ZnO(s) exhibited higher rate and extent of cure over that of 5phr and 2phr of conventional ZnO compounds. This indicates ZnO(p) and ZnO(s) with larger surface area developed the full potential of the accelerator, there by making vulcanization faster. Scorch safety has increased, and cure time was found to be lower for ZnO(p) and ZnO(s) compounds compared to conventional ZnO compounds. Compounds with 2phr ZnO(p) and ZnO(s) show faster curing compared to compounds containing 1phr ZnO(p) and ZnO(s). 4.3.2 Properties of gum composites Tensile properties Compound Table 4.4 Tensile properties of gum vulcanizates Tensile strength (MPa) Elongation at break (%) Tensile modulus at300% elongation (MPa) Tear strength (N/mm) N-1 23.02 1735 1.17 38 N-2 22.94 1591 1.46 40 N-3 23.06 1656 1.25 40 N-4 20.80 1899 1.04 33 Tensile properties of gum vulcanizates with ZnO(c), ZnO(p) and ZnO(s) are shown in Table 4.4. Gum vulcanizate with 2phr conventional ZnO has relatively low tensile properties compared to vulcanizates with 5phr conventional ZnO, 2phr ZnO(p) and ZnO(s). Modulus and tear strength values for vulcanizates with 2phr ZnO(p) and ZnO(s) are slightly greater than vulcanizate with 5phr ZnO(c). Elongation at break is decreased for N-2 and N-3 vulcanizates compared to N-1 vulcanizate. Tensile strength values for N-2 and N-3 vulcanizates are comparable with N-1 vulcanizate. These values show that the reinforcement effect of ZnO(p) and ZnO(s) are influenced by the larger surface area of activator. Small size of particles can give good 81
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Studies on the use
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WxvÄtÜtà|ÉÇ I hereby declare t
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My heartfelt thanks are also due to
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The use of prepared zinc oxides as
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2.2.10 Characterization techniques
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Part@ B 7.3.1 Characterization - su
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Introduction 1.1 Composites 1.1 Com
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Introduction of reinforcement and m
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Nanophase material: They are same a
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Introduction developed at Oxford Un
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Introduction Rubbers are broadly cl
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Introduction The polymers are prepa
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1.4.1 Zinc oxide Introduction Zinc
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Introduction and tinted rubber comp
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Pharmaceutical industry Introductio
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Introduction textiles contain ZnO,
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1.4.2a. Carbon blacks Introduction
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Introduction especially glass and c
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Introduction properties, filler cha
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Introduction coupling agent in sili
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Page 45 and 46: Introduction It has been reported t
Page 47 and 48: Introduction The external manifesta
Page 49 and 50: Introduction concern for a clean en
Page 51 and 52: 12. C.R.Martin, Chem. Mater, 1996,
Page 53 and 54: 41. E.J.Stewart, J.Elastomers plast
Page 55 and 56: Introduction 69. J.B. Donnet (Ed),
Page 57 and 58: Introduction 100. C.T.Kresge, M.E.L
Page 59 and 60: Introduction 129. E.R.Ericsson, R.A
Page 61 and 62: Chapter 2 47 In a particular experi
Page 63 and 64: Chapter 2 Stearic acid (co-activato
Page 65 and 66: Chapter 2 roll with mill opening at
Page 67 and 68: Chapter 2 were carried out at a cro
Page 69 and 70: Chapter 2 2.2.4 Strain-sweep studie
Page 71 and 72: Chapter 2 2.2.6 Bound rubber conten
Page 73 and 74: Chapter 2 Surface area 59 Surface a
Page 75 and 76: Preparation and characterization of
Page 77 and 78: 3.2.2 Method I- Precipitation metho
Page 79 and 80: Energy dispersive X-ray spectrometr
Page 85 and 86: 3.4.9 Differential scanning calorim
Page 87 and 88: 3.6 References Preparation and char
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Page 103 and 104: 4.5 References Use of nano zinc oxi
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Page 107 and 108: Chapter 5 93 Ingredient phr Table 5
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Page 113 and 114: Chapter 5 99 Table 5.8 Reinforcing
Page 115 and 116: Chapter 5 101 Hours Table 5.11 Agei
Page 117 and 118: Chapter 5 5.5 References 103 1. D.C
Page 119 and 120: Chapter 6 105 Fatty acids as co-act
Page 121 and 122: Chapter 6 107 Physical properties s
Page 123 and 124: Chapter 6 The cure rate index of gu
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Page 127 and 128: Chapter 6 113 Table 6.6 Reinforcing
Page 129 and 130: Chapter 6 115 Tensile modulus (Mpa)
Page 131 and 132: Chapter 6 6.4 Conclusions 117 1. Gu
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Use of antioxidant modified precipi
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Part@ B Use of antioxidant modified
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Thermal ageing studies Use of antio
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7.9 References Use of antioxidant m
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Products from rice husk as filler i
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Rubber compounding Products from ri
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Soxhlet extraction Products from ri
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8.3.4 Bound rubber content Products
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. Hardness (Shore A ) 70 60 50 40 3
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8.8 References 1. V.M.H. Govindaro
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Summary and Conclusions Polymers ar
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Summary and Conclusion compounds an
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ASTM : American Society for Testing
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A. International/National journals
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P.M.SABURA BEGUM Senior Scale Lectu
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