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

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Chapter 7 silica particles are reduced by the antioxidant which acts as lubricants. So it reduces the heat developed by the frictional strain. 7.3.5 Rubber-filler interaction studies With antioxidant IPPD 130 The complex modulus G* of composites containing antioxidant modified silica and neat silica were measured before and after curing. The variation of G* with strain for uncured and cured samples are shown in figure 7.4(a,b) respectively. The complex modulus at low strains is a measure of the filler-polymer interaction. 21-23 At low strains the complex modulus of antioxidant modified silica filled composite are remarkably high compared to higher strain. This may be due to the hydrogen bonding between silanol groups and –NH groups in the antioxidant at lower strain. G*(MPa) 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Strain Sweep Uncured NR + Neat Silica NR + Modified Silica 0.56 0.12 10.04 100.02 Strain (%) G*(MPa) 4 3.5 3 2.5 2 1.5 1 0.5 0 Strain sweep cured NR + Neat Silica NR + Modified Silica 0.56 0.12 10.04 100.02 Strain (%) (a) (b) Figure 7.4 (a) Variation of complex modulus with strain for uncured compounds (b) Variation of complex modulus with strain for cured compounds 7.3.6 Ageing studies a) Thermal ageing studies Figure 7.5(a) shows variation in the tensile strength of the filled vulcanizates of NR with time of ageing. The vulcanizate containing IPPD modified silica shows good resistance when the ageing time is increased to 96 hrs. This shows that antioxidant is getting coated over the silica surface and gets uniformly distributed in the rubber matrix.
Use of antioxidant modified precipitated silica in natural rubber, chloroprene rubber and styrene butadiene rubber Figure 7.5(b) shows the change in modulus of the vulcanizates with ageing time. The increase in modulus after 96 hrs may be due to the increase in total crosslink density. Figure 7.5(c) shows the change in elongation at break of the vulcanizates with ageing time. The vulcanizate filled with antioxidant modified silica shows better retention in elongation at break after ageing. This again shows that antioxidant modified silica can improve the ageing resistance of the NR vulcanizate. Figure 7.5(d) shows the tear strength of the vulcanizates with time of ageing. The vulcanizates containing antioxidant modified silica shows good resistance when the ageing time is increased to 96 hrs. This may be due to the increased rubber filler interactions in antioxidant modified silica vulcanizates. Tensile strength (MPa) Elongation at break (%) 25 24 23 22 21 20 19 18 1050 1000 950 900 850 800 750 700 650 600 550 Precipitated silica and IPPD IPPD modified precipitatedsilica 0 20 40 60 80 100 Hours Precipitated silica and IPPD IPPD modified precipitated silica 0 20 40 60 80 100 Hours (c) (a) 0 20 40 60 80 100 Figure 7.5 Variation in tensile properties of NR vulcanizates with time of ageing at 100°C Tensile modulus (MPa) Tear strength (N/mm) 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 60 57 54 51 48 45 42 Precipitated silica and IPPD IPPD modified precipitated silica Hours (b) Precipitated silica and IPPD IPPD modified precipitated silica (d) 0 20 40 60 80 100 Hours 131
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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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Introduction amphiphilic di and tri
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Introduction It has been reported t
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Introduction The external manifesta
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Introduction concern for a clean en
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12. C.R.Martin, Chem. Mater, 1996,
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41. E.J.Stewart, J.Elastomers plast
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Introduction 69. J.B. Donnet (Ed),
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Introduction 100. C.T.Kresge, M.E.L
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Introduction 129. E.R.Ericsson, R.A
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Chapter 2 47 In a particular experi
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Chapter 2 Stearic acid (co-activato
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Chapter 2 roll with mill opening at
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Chapter 2 were carried out at a cro
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Chapter 2 2.2.4 Strain-sweep studie
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Chapter 2 2.2.6 Bound rubber conten
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Chapter 2 Surface area 59 Surface a
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Preparation and characterization of
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3.2.2 Method I- Precipitation metho
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Energy dispersive X-ray spectrometr
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3.4.9 Differential scanning calorim
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3.6 References Preparation and char
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Use of nano zinc oxide in natural r
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Use of nano zinc oxide in natural r
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Page 107 and 108: Chapter 5 93 Ingredient phr Table 5
Page 109 and 110: Chapter 5 95 Torque (dNm) 6.5 6.0 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
Page 133 and 134: Use of antioxidant modified precipi
Page 139 and 140: Mix Use of antioxidant modified pre
Page 143: Crosslink density Use of antioxidan
Page 151 and 152: Part@ B Use of antioxidant modified
Page 157 and 158: Thermal ageing studies Use of antio
Page 161 and 162: 7.9 References Use of antioxidant m
Page 163 and 164: Products from rice husk as filler i
Page 167 and 168: Rubber compounding Products from ri
Page 169 and 170: Soxhlet extraction Products from ri
Page 173 and 174: 8.3.4 Bound rubber content Products
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Page 185 and 186: 8.8 References 1. V.M.H. Govindaro
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Page 191 and 192: ASTM : American Society for Testing
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P.M.SABURA BEGUM Senior Scale Lectu
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