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 VÉÇàxÇàá 5.1 Introduction 5.1 Introduction 5.2 Experimental 5.3 Results and discussion 5.4 Conclusions 5.5 References Synthetic rubbers are more uniform in quality and compounds are more consistent in both processing and product properties. 1 There are polar and non-polar synthetic rubbers. Polychloroprene known as neoprene is a polar rubber and is generally considered as a special purpose rubber being used for applications requiring oil and solvent resistance. There has been a long standing commercial need for oil resistant elastomers. 2 For example, oil resistant materials are very important to the automotive industry since a variety of components may come in contact with a number of fluids. In the specific case of engine seals, it is important that they be able to withstand the fluids they are sealing without losing their ability to maintain the seal either by becoming too soft or too brittle. 3 Examining the specific reasons for the chemical resistance of polymers, it can be seen that polar side groups tend to provide resistance to swelling in hydrocarbon oils. 4 This induces slight electronegative charge on the electronegative atom with a slight positive around the carbon atom. The dipole moment produced tends to provide oil resistance. As the electronegativity of the side chain group increases on a polymer, so does its
Chapter 5 oil resistance to oil swelling. Polychloroprene is structurally similar to polyisoprene with a chlorine atom replacing methyl group attached to the back bone. This chlorine atom is more electronegative than the methyl group, and as such increases the resistance of the material. Chloroprene rubbers are generally vulcanized using metal oxide. 5-6 The primary cross linking agent is zinc oxide which is used along with magnesium oxide. Lead oxides are sometime used when low water absorption is required. Two routes have been proposed for the curing. One requires the incorporation of zinc atoms into crosslink (scheme 5.1), the other leads to ether cross links (scheme 5.2). CH2 CH2 CH2 2CH2= CH- C-Cl + ZnO +MgO → CH2 =CH-C-O-Zn-O-C-CH=CH2 + MgCl2 91 Scheme 5.1 – Mechanism of cross linking in 1,2-polychloroprene involving incorporation of Zn atom ZnCl2 +MgO → ZnO +MgCl2 Scheme 5.2 – Mechanism of showing cross linking in 1,2– polychloroprene through the formation of ether cross links
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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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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
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: 4.5 References Use of nano zinc oxi
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
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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Use of antioxidant modified precipi
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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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