Mixing of Rubber

Description

"Introducing the new 'Classic Rapra Reprint' Series. Mixing of Rubber is the first book in a series of Classic Rapra Reprints. We have searched our previously published and successful reference books, and found some real gems! The content is sure to be of interest to those in the Rubber Mixing Industry, both new to industry and those more experience, all will benefit... Since the discovery of vulcanisation in the nineteenth century, rubber has been a major industrial product. From its inception, the use of vulcanising agents, reinforcing fillers and other additives has been a major feature of the rubber industry. Innumerable articles and texts attest to the chemist's skill in balancing the chemical and physical properties of the manufactured products. Mixing as a general operation may be considered as three basic processes occurring simultaneously. Simple mixing ensures t h a t the mixture has a uniform composition throughout its bulk, at least when viewed on a scale large compared to the size of the individual particles. In the case of solids blending (Chapter 11), the particle size need not change, but the distribution of particles throughout the mixture approaches a random distribution. If the shear forces are sufficiently large, particles may fracture, as in dispersive mixing, and the polymer may flow, as in laminar mixing (Chapter 111). In both of these processes, the size of the original particles or fluid elements changes because o f t h e mixing process. Then the properties of the mixture depend upon the size of the basic structures reached during mixing. In the case of laminar mixing, the size may be the striation thickness of a hypothetical fluid element, which is inversely related to the total shear strain. If relatively strong particles, or aggregates of particles, are present, these must be reduced in size by the action of forces generated by flow in the mixer. Then the size is the actual additive particle size. 1 Introduction......Page 10 2.1 The Statistical Description of Mixing......Page 14 2.1.1 Confidence Limits......Page 18 2.1.2 Significance Tests......Page 19 2.2 Definitions of Mixedness......Page 24 2.3 The Kinetics of Simple Mixing......Page 27 2.4 Multicomponent Mixtures and Markov Chains......Page 33 2.5.1 Tumble Blenders......Page 39 2.5.2 Blade Mixers......Page 42 2.5.3 Air and Gravity Feed Mixers......Page 45 2.6 Summary......Page 49 References......Page 50 3.1 Laminar Shear Mixing......Page 52 3.1.1 Calculation of Striation Thickness......Page 54 3.1.2 The Effect of Streamline Orientation......Page 59 3.2 Dispersive Mixing......Page 61 3.2.1 Calculation of Forces on a Particle......Page 62 3.2.2 Flow in Thin Channels......Page 65 3.2.3 The Kinetics of Particle Dispersion......Page 69 3.3 Masterbatches......Page 71 3.4 Incorporation of Carbon Black......Page 74 References......Page 76 4 The Milling of Rubbers......Page 78 4.1 The Analysis of a Calendar......Page 79 4.1.1 Basic Flow Equations......Page 80 4.1.2 Power-law Fluids......Page 89 4.1.3 Scaling Laws......Page 93 4.2 Processing Instabilities......Page 98 4.3 Heat Transfer......Page 105 4.4 Scale-up Alternatives......Page 108 4.5 Commercial Mills......Page 113 References......Page 114 5.1 Flow in an Internal Mixer......Page 116 5.2 Analysis of an Internal Mixer......Page 121 5.3 Alternative Mixer Models......Page 128 5.4 Heat Transfer in Internal Mixers......Page 135 5.5 The Effect of Ram Pressure......Page 140 5.6 Commercial Internal Mixers......Page 143 5.7 Scaling Laws and Dump Criteria for Internal Mixers......Page 146 5.7.1 Geometric Similarity......Page 148 5.7.2 Maximum Shear Stress......Page 151 5.7.3 Total Shear Strain......Page 154 5.7.4 Work Input......Page 157 5.7.5 Constant Mixing Time......Page 162 5.7.6 Constant Stock Temperature......Page 163 5.7.7 Constant Weissenberg and Deborah Numbers......Page 164 5.7.8 Graetz and Griffi ths Numbers......Page 165 References......Page 167 6.1 Mixing in Single Screw Extruders......Page 170 6.1.1 Mathematical Formulation......Page 171 6.1.2 Non-Standard Geometry......Page 178 6.2 Mixing in Two-Screw Extruders......Page 182 References......Page 184 7.1.2 Spray Drying......Page 186 7.2 Mixing Powdered Rubbers......Page 187 7.4 Evaluation of Powdered Rubbers......Page 188 References......Page 190 Index......Page 192