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

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Use of nano zinc oxide in chloroprene rubber Chloroprene is not characterized by one out standing property, but its balance of properties is unique among synthetic elastomers. It has good mechanical strength, high ozone and weather resistance, good ageing resistance, low flammability, good resistance to chemicals, good oil and fuel resistance and adhesion to many substrates. Vulcanization of polychloroprene can be accelerated using accelerator like ethylene thiourea (NA22). It has been observed that study of nano zinc oxides (ZnO(p) and ZnO(s)) in natural rubber 7 improved the mechanical properties and reinforcement. The present study explains the use of ZnO(p) and ZnO(s) in chloroprene rubber in comparison to conventional ZnO. The cure characteristics, mechanical properties and ageing resistance are compared with reference compounds prepared from CR and conventional zinc oxide (ZnO(c)). 5.2 Experimental Materials: Neoprene–W manufactured by M/s Dupont, USA with Mooney viscosity (ML (1+4) 100°C) 47, light magnesium oxide, stearic acid, high abrasion furnace black, dioctyl phthalate (DOP), antioxidant HS, conventional ZnO, prepared zinc oxides (ZnO(p), ZnO(s)) and ethylene thiourea Na22. Preparation of the composites Table 5.1. The base formulation for the preparation of composites is given in the 92
Chapter 5 93 Ingredient phr Table 5.1 Formulations of gum and filled CR compounds C -1 C - 2 C - 3 C-4 C - 5 C - 6 C- 7 C-8 C - 9 C-10 Neoprene-W 100 100 100 100 100 100 100 100 100 100 Light MgO 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 Stearic acid 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 HS 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 HAF - - - - 40 40 40 40 40 40 DOP - - - - 8 8 8 8 8 8 ZnO(c) 5 - - 2 5 - - 2 - - ZnO(p) - 2 - - - 2 - - 1 - ZnO(s) - - 2 - - - 2 - - 1 Na 22 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Mixing was done in a laboratory size (16 X 33 cm) two roll mill at a friction ratio of 1:1.25 as per ASTM D 3182 (1982). Testing The cure characteristics of the mixes were determined using Rubber Process Analyzer RPA 2000, as per ASTM standard, D 2084–01. Subsequently, the rubber compounds were vulcanized up to their 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 modulus, tensile strength, elongation at break, tear strength, hardness, heat build–up, compression set, abrasion loss, flex resistance and ageing resistance were studied as per the respective ASTM standards. Swelling studies of the compounds were carried out in methyl ethyl ketone and crosslink densities were calculated.
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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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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
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: Chapter 5 oil resistance to oil swe
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
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
Page 125 and 126: Chapter 6 show better mechanical pr
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 and 144: Crosslink density Use of antioxidan
Page 151 and 152: Part@ B Use of antioxidant modified
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Thermal ageing studies Use of antio
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Use of antioxidant modified precipi
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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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