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

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Chapter 7 142 Table 7.12: Formulation of the mixes Ingredients (phr) I-1 I-2 SBR 1502 100 100 Zinc oxide 5.0 5.0 Stearic acid 2.0 2.0 Antioxidant modified silica 51 - Precipitated silica - 50 Antioxidant IPPD - 1.0 Naphthenic oil 8.0 8.0 Diethylene glycol 1.0 1.0 CBS 0.8 0.8 TMTD 0.25 0.25 Sulphur 2.0 2.0 Compounds were prepared on a laboratory size (16 x 33 cm) two roll mill at a friction ratio of 1:1.25 as per ASTM 3184-89 (2001). After complete mixing of the ingredients, the stock was passed out at fixed nip gap. The samples were kept over night for maturation. The cure characteristics of all mixes were determined using Rubber Process Analyser RPA 2000, as per ASTM standard D 2084-01. Subsequently the rubber compounds were vulcanized upto the 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 tensile strength, modulus, elongation at break, tear strength, hardness, abrasion loss, heat build-up, compression set and flex crack resistance were studied as per the respective ASTM standards.
Thermal ageing studies Use of antioxidant modified precipitated silica in natural rubber, chloroprene rubber and styrene butadiene rubber Thermal ageing was carried out at temperature of 100°C for 48, 72 and 96 hrs as per ASTM D 573-1999. 7.7 Results and discussion 7.7.1: Cure characteristics Cure characteristics of the SBR compounds with an optimum concentration of 50phr precipitated silica and 1phr antioxidant IPPD are shown in the Table 7.13. Mix Table 7.13 Cure characteristics of SBR compounds Min torque (dNm) Max torque (dNm) Scorch time (min) Optimum cure time (min) Cure rate index (%) I-1 2.28 18.98 3.73 8.53 20.83 I-2 2.08 17.73 5.52 14.17 11.56 Antioxidant modified silica filled compounds showed higher cure rate and extent of cure over that of neat silica filled compounds. The optimum cure time was found to be lower for antioxidant modified silica compounds. This is due to the improved rubber-filler interaction. Silica surface has a tendency to absorb moisture and curatives which influences the curing reaction and the properties of the final product. This problem can be overcome by modifying silica with antioxidant. The antioxidant coating prevents silica from further absorption of moisture and curatives. The antioxidant coating improves the dispersion of silica in rubber matrix further. 7.7.2 Tensile properties Tensile properties of SBR vulcanizates with antioxidant (IPPD) modified silica and with neat silica are shown in Table 7.14. 143
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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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Introduction 69. J.B. Donnet (Ed),
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Introduction 100. C.T.Kresge, M.E.L
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Introduction 129. E.R.Ericsson, R.A
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Chapter 2 47 In a particular experi
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Chapter 2 Stearic acid (co-activato
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Chapter 2 roll with mill opening at
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Chapter 2 were carried out at a cro
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Chapter 2 2.2.4 Strain-sweep studie
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Chapter 2 2.2.6 Bound rubber conten
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Chapter 2 Surface area 59 Surface a
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Preparation and characterization of
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3.2.2 Method I- Precipitation metho
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Energy dispersive X-ray spectrometr
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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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