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

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Chapter 1 hardness and abrasion resistance. In the ASTM D 1765 classification for carbon blacks about 42 commercial blacks were recognized. 1.4.2b. Non-black fillers 22 Non-black reinforcing fillers for rubber include hydrated silica, calcium silicate, zinc oxide, the fine particle size precipitated calcium carbonate etc. The use of coupling agent is more relevant with these non- black fillers. 39-42 Reinforcement by silica and silicates has been reviewed by Wagner. 43 Non-black fillers include a range of inorganic materials with a variety of particle shapes and sizes. It is available in a broad range of sizes from about 10 to 0.015 microns. These fillers can broadly be classified as; a) fillers used to reduce cost b) semi-reinforcing filler c) reinforcing filler. Earlier non-black fillers used were mainly naturally occurring minerals or by- products of manufacturing such as clay, whiting, barytes, zinc oxide, zinc sulphide, blanc-fixe, mica, asbestos, kieselguhr, magnesium carbonate, iron oxide, litharge etc. They were used in rubber to reduce tack, increase hardness, improve durability and reduce cost. 44-46 Other important non-black fillers being used in the elastomer industry are aluminium hydrate, aluminium oxide and titanium dioxide. The need for more reinforcing non-black fillers in many rubber applications led to the introduction of calcium carbonate, calcium silicates, hydrated silica and fumed silica between 1940 and 1960. These were characterized by very small particle size much smaller than the natural products and similar to the reinforcing carbon blacks. Since then a lot of developments and refinements in hydrated silica and fumed silica have taken place resulting in a number of grades for specific applications. 47 Silica Silica is a crystalline compound occurring abundantly as quartz, sand and many other minerals and is used to manufacture a variety of materials,
Introduction especially glass and concrete. Natural silica is non-reinforcing and has been used as a filler, only to reduce the cost. The synthetic ones are reinforcing and nowadays have particle sizes as small as the carbon black besides an extremely reactive surface. 48 Important natural varieties are silica (amorphous), silica (crystalline), silica diatomaceous (fossil origin) and silica (microcrystalline). Types of synthetic silica are precipitated, pyrogenic, aerogels and hydrogels. Of these varieties, precipitated silica and pyrogenic (fumed) silica are being used for elastomer reinforcement. Production and characterization of silica Acidification of alkali silicate solutions under controlled conditions produces precipitated silica. 49 Na2SiO3 + HCl→ 2NaCl + H2O + SiO2 ………………1.1 Colloidal pyrogenic silica is produced by reaction of silicon tetrachloride at high temperatures with water. SiCl4 + 2H2O → SiO2 + 4HCl ………………………………..1.2 The reaction products are quenched immediately after coming out of the burner. Pyrogenic silica is too active and expensive. 50 Precipitated silica is silicon dioxide containing about 10-14% water, with particle size in the range 1-40 nm. They are reinforcing fillers giving composites of high tensile strength, tear resistance, abrasion resistance and hardness. It is being used in the manufacture of translucent and colored products, shoe soling, tyres and other mechanical rubber goods. Fumed or pyrogenic silica is silicon dioxide containing less than 2% combined water. These silica particles are highly reinforcing fillers of very small particle size, giving high tensile strength, tear resistance and abrasion resistance particularly to silicon rubbers. 45 Characterization of silica filler is also based on particle size and specific surface area. Surface area measurement is usually done by nitrogen 23
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 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: 1.4.2a. Carbon blacks Introduction
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 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
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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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