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

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Chapter 1 bonds are less active chemically than the double bonds of NR. Hence, SBR shows a slower curing than NR and more accelerators or more active accelerator system is required. 12 Styrene butadiene rubber (SBR), the widely used and easily available synthetic rubber, has unique place among elastomers. This is because practically all automotive tires use SBR, especially in the tread, due to its wear advantage over natural rubber treads. 1.4 Compounding ingredients In most of the rubber formulations there are many ingredients, which are meant for specific purposes. Developments of rubber formulations that are environmentally safe, factory-processible, cost-competitive with other compounds in the same applications and are able to provide satisfactory properties and service life are getting much importance. These requirements put considerable demands on the compounder, who must have extensive knowledge of materials having these properties in elastomer products. Generally in rubber compounding, we can classify the materials based on their functions. These include vulcanizing or cross linking agents, accelerators, activators retarders, process aids, softeners and plasticizers, fillers and other miscellaneous materials. The cross linking efficiency of some vulcanizing agents in natural rubber was assessed by Lorenz and Parks. 29-30 It is generally assumed that the presence of filler might affect the efficiency of the curing agent. The filler- curing agent interaction might influence the rate of cross linking which give vulcanization rates in filled stocks different from those in gum stocks. Pal et al. 31-32 have studied the effect of reinforcing black, silica and clay on vulcanization.
1.4.1 Zinc oxide Introduction Zinc oxide is one of the basic components of rubber compounds. It acts as an activator of rubber cross linking by sulphur or sulphur donors. It increases the amount of bound sulphur as well as the efficiency of crosslink system. Borros and Agullo 33 made an investigation on the effect of sulphenamide accelerating system on natural rubber vulcanizations and on the active role of zinc oxide and the olefinic chain in NR. Recently Kruger and McGill have published papers on the interactions between the components of the cross linking systems. 34-35 Importance of ZnO 36 Perhaps the most common use of zinc is for healing and protecting the skin. Zinc oxide has been used for generations to soothe diaper rash and relieve itching. Zinc oxide is a natural sunscreen to protect chopped lips and skin from the sun’s UV rays. Zinc sulfate can be taken orally to effectively treat acne, while it also comes in a topical form to improve healing of wounds caused by surgical incision, burns or other skin irritations. Zinc alleviates sun burns and blisters and can also be used as an anti-inflammatory. In rubber The rubber industry, in its development over the past one hundred years, has utilized an increasing number of the many optical, physical and chemical properties of ZnO. ZnO proved the most effective activator to speed up the rate of cure with the new accelerators. Heavy-duty pneumatic tyres carry high loadings of ZnO for heat conductivity as well as reinforcement since heat build-up is critical at their higher operating speeds compared with their solid-rubber counterparts. 13
Page 2: Studies on the use
Page 5 and 6: WxvÄtÜtà|ÉÇ I hereby declare t
Page 7 and 8: My heartfelt thanks are also due to
Page 9 and 10: The use of prepared zinc oxides as
Page 11 and 12: 2.2.10 Characterization techniques
Page 13 and 14: 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: Introduction The polymers are prepa
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
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Page 67 and 68: Chapter 2 were carried out at a cro
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Page 71 and 72: Chapter 2 2.2.6 Bound rubber conten
Page 73 and 74: Chapter 2 Surface area 59 Surface a
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3.2.2 Method I- Precipitation metho
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Energy dispersive X-ray spectrometr
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Preparation and characterization of
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Preparation and characterization of
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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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Tear Strength (N/mm) 120 100 80 60
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4.5 References Use of nano zinc oxi
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Chapter 5 oil resistance to oil swe
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Chapter 5 93 Ingredient phr Table 5
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Chapter 5 95 Torque (dNm) 6.5 6.0 5
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Chapter 5 97 Other technological pr
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Chapter 5 99 Table 5.8 Reinforcing
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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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