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

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Chapter 7 Testing 138 The cure characteristics of all mixes were determined using Rubber Process Analyzer RPA 2000, as per ASTM standard D 2084-01. Subsequently the rubber compounds were vulcanized upto the optimum cure time at 150°C in an electrically heated hydraulic press. The mouldings were cooled quickly in water at the end of the curing cycle and stored in a cool dark place for 24 hrs prior to physical testing. Physical properties such as tensile strength, modulus, elongation at break, tear strength, hardness, abrasion loss, heat build-up, compression set, and flex resistance were studied as per the respective ASTM standards. Thermal ageing studies Thermal ageing was carried out at temperature of 100°C for 48 hrs, 72 hrs and 96 hrs as per the ASTM D 573-1999. 7.5 Results and discussion 7.5.1 Cure characteristics Mix Table 7.9 Cure characteristics of CR compounds Min torque (dNm) Max torque (dNm) Scorch time (min) Optimum cure time (min) Cure rate index (%) H-1 2.97 45.18 1.71 30 3.53 H-2 3.56 36.90 1.98 30 3.56 Table 7.9 gives the cure characteristics of the neoprene compounds with an optimum concentration of 50phr silica and 1phr antioxidant (IPPD). H-1 mix is with 51phr of prepared antioxidant modified silica and H-2 mix is with 50phr of neat precipitated silica and 1phr of antioxidant (IPPD). Compounds containing antioxidant modified silica and with neat precipitated silica shows comparable cure rate. It is found that antioxidant modified silica
Use of antioxidant modified precipitated silica in natural rubber, chloroprene rubber and styrene butadiene rubber mix increases the torque values. The maximum torque is the measure of crosslink density and stiffness in the rubber. This increase in torque value for antioxidant modified silica mix may be due to the surface modification of silica with antioxidant. 7.5.2 Tensile properties Tensile properties of CR vulcanizates with antioxidant (IPPD) modified silica and with neat precipitated silica are shown in Table 7.10. Mix Table 7.10: Tensile properties of CR vulcanizates Tensile strength Mpa 300% Tensile modulus, Mpa Elongation at break (%) Tear strength N/mm H-1 16.05 2.70 1237 42 H-2 15.01 2.56 1275 40 The tensile properties of CR vulcanizates with antioxidant modified silica and with neat silica are comparable. 7.5.3 Other technological properties Other technological properties like hardness, abrasion loss, heat build- up and flex resistance of the CR vulcanizates are given in the Table 7.11. Mix Hardness (shore A) Table 7.11: Other Technological properties Compression set (%) Abrasion loss (cc/hr) Heat build-up (∆T) 0 C Flex resistance (cycles) H-1 65 48 1.39 20.1 92539 H-2 65 50 1.40 22.3 72284 Hardness was found to be comparable for vulcanizates with antioxidant modified silica and with neat silica. Compression set, abrasion loss and heat build-up are found to be comparatively low for vulcanizate 139
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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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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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Page 139 and 140: Mix Use of antioxidant modified pre
Page 143 and 144: Crosslink density Use of antioxidan
Page 151: 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
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Page 167 and 168: Rubber compounding Products from ri
Page 169 and 170: Soxhlet extraction Products from ri
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Page 191 and 192: ASTM : American Society for Testing
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