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

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Cure characteristics Experimental Techniques and Materials used Cure characteristics of the mixes were determined as per ASTM D 2084–1995 using Rubber Process Analyser (RPA 2000–Alpha technologies). It uses two directly heated, opposed biconical dies that are designed to achieve a constant shear gradient over the entire sample chamber. The sample of approximately 5 g was placed in the lower die that is oscillated through a small deformation angle (0-2°) at a frequency of 50 cpm. The torque transducer on the upper die senses the forces being transmitted through the rubber. The torque is plotted as a function of time and the curve is called a cure graph. The important data that could be taken from the torque-time curve are minimum torque (ML), maximum torque. (MH), scorch time (T10), optimum cure time (T90) and cure rate index. Cure rate index was calculated from the cure graph using the equation 2.1. Cure rate index = 100/ t90 – ts2 ……………….. 2.1 Where t90 and ts2 are the times corresponding to the optimum cure and two units above minimum torque respectively. Moulding Vulcanization of various test samples was carried out in an electrically heated hydraulic press having 45 cm x 45 cm platen at 150 °C at a pressure of 200 kg /cm 2 on the mould up to optimum cure times. Moulded samples were conditioned for 24 hrs, before testing. 2.2.2 Physical Testing Modulus, tensile strength and elongation at break (Stress – strain properties) These tests were carried out according to ASTM D 412–1998, using dumbbell specimens. Test specimens were punched out from the molded sheets using the C-type die, along the mill grain direction. The measurements 52
Chapter 2 were carried out at a cross head speed of 500 mm/min on a Shimadzu Model AGI Universal Testing Machine according to ASTM standards, D 412–68 and D 624–54 respectively. Tear strength 53 Tear resistance of the samples was tested as per ASTM D 624–1998, using un-nicked 90° angle test specimens that were punched out from the moulded sheets, along the mill grain direction. The measurements were carried out a crosshead speed of 500 mm per minute on a Shimadzu Model AGI Universal Testing Machine according to ASTM standards, D 412–68 and D 624–54 respectively. The tear strength was reported in N/mm. Hardness The testing was done as per ASTM D 2240–1997 using Shore A type Durometer. 3 Readings were taken after 15 seconds of the indentation when firm contact has been established with the specimens. Abrasion resistance The abrasion resistances of the samples were studied with a DIN Abrader (DIN 53516). Moulded samples of 6 ± 0.2 mm diameter and 12 mm thickness were prepared as per ASTM D 3183 and abrasion loss was measured as per ASTM D 5963–04. Abrasion loss was calculated using the equation 2.2. Abrasion loss = (loss of wt. /sp.gr.) …….………. 2.2 Compression set. The samples (1.25 cm thick and 2.8 cm diameter) in duplicate compressed to a constant deflection (25 %) were kept in an air oven at 70 °C for 22 hrs (ASTM D 395-1998 method B). 4 The samples were taken out,
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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
Page 15 and 16: Introduction 1.1 Composites 1.1 Com
Page 17 and 18: Introduction of reinforcement and m
Page 19 and 20: Nanophase material: They are same a
Page 21 and 22: Introduction developed at Oxford Un
Page 23 and 24: Introduction Rubbers are broadly cl
Page 25 and 26: Introduction The polymers are prepa
Page 27 and 28: 1.4.1 Zinc oxide Introduction Zinc
Page 29 and 30: Introduction and tinted rubber comp
Page 31 and 32: Pharmaceutical industry Introductio
Page 33 and 34: Introduction textiles contain ZnO,
Page 35 and 36: 1.4.2a. Carbon blacks Introduction
Page 37 and 38: Introduction especially glass and c
Page 39 and 40: Introduction properties, filler cha
Page 41 and 42: Introduction coupling agent in sili
Page 43 and 44: Introduction amphiphilic di and tri
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: Chapter 2 roll with mill opening at
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
Page 89 and 90: Use of nano zinc oxide in natural r
Page 101 and 102: Tear Strength (N/mm) 120 100 80 60
Page 103 and 104: 4.5 References Use of nano zinc oxi
Page 105 and 106: Chapter 5 oil resistance to oil swe
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
Page 111 and 112: Chapter 5 97 Other technological pr
Page 113 and 114: Chapter 5 99 Table 5.8 Reinforcing
Page 115 and 116: Chapter 5 101 Hours Table 5.11 Agei
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Chapter 5 5.5 References 103 1. D.C
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Chapter 6 105 Fatty acids as co-act
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Chapter 6 107 Physical properties s
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Chapter 6 The cure rate index of gu
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Chapter 6 show better mechanical pr
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Chapter 6 113 Table 6.6 Reinforcing
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Chapter 6 115 Tensile modulus (Mpa)
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Chapter 6 6.4 Conclusions 117 1. Gu
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Use of antioxidant modified precipi
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Mix Use of antioxidant modified pre
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Crosslink density Use of antioxidan
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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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