Front cover -- Polymer Foams Handbook -- Copyright page -- Contents -- Foreword -- Acknowledgements -- Chapter 1. Introduction to polymer foam microstructure -- 1.1 Open- and closed-cell foams -- 1.2 Relative density: wet and dry foams -- 1.3 Edges -- 1.4 Vertices -- 1.5 Faces -- 1.6 Cell geometry -- 1.7 Cells -- 1.8 Foam microstructural models -- 1.8.1 Lattice micromechanics models -- 1.8.2 Cell (bubble) growth -- 1.8.3 Irregular models -- 1.9 Bead foams -- References -- Chapter 2. Polyurethane foams: processing and microstructure -- 2.1 Introduction -- 2.2 PU chemistry -- 2.3 PU foam processes -- 2.3.1 Slabstock foam -- 2.3.2 Moulded PU foam -- 2.3.3 Slow-recovery foams -- 2.4 PU microstructure -- 2.5 Effect of microstructure on mechanical properties -- 2.6 PU foam microstructure -- 2.6.1 Slabstock PU foams -- 2.6.2 Moulded foams -- 2.6.3 Rebonded PU foams -- 2.6.4 Slow-recovery PU foams -- Summary -- References -- Chapter 3. Foamed thermoplastics: microstructure and processing -- 3.1 Introduction -- 3.2 Polyolefins -- 3.2.1 PEs and copolymers -- 3.2.2 Blends -- 3.2.3 Ethylene styrene 'interpolymers' -- 3.2.4 Ethylene-propylene-diene monomer -- 3.2.5 Polypropylenes -- 3.3 Processing -- 3.3.1 Extrusion of thermoplastic foam sheet -- 3.3.2 Melt rheology suitable for foaming -- 3.3.3 Stages in closed-cell foam development -- 3.3.4 Post-extrusion shrinkage -- 3.3.5 Oriented PP foams - Strandfoam -- 3.4 Foam crystallinity and crystal orientation -- Summary -- References -- Chapter 4. Bead foam microstructure and processing -- 4.1 Introduction -- 4.2 Processing -- 4.2.1 Bead preparation -- 4.2.2 Steam moulding -- 4.2.3 Dimensional stability post-moulding -- 4.3 Microstructure -- 4.3.1 Bead shape and fusion -- 4.3.2 Density variations in large mouldings -- 4.3.3 The effects of processing on properties -- 4.3.4 Bead shape variation.

4.3.5 Microstructural models -- 4.4 Specific bead foams -- 4.4.1 PP bead foam: EPP -- 4.4.2 PS bead foam: EPS -- References -- Chapter 5. Simple mechanical tests -- 5.1 Introduction -- 5.2 Stiffness and strength of structures -- 5.3 Stress-strain responses and material parameters -- 5.3.1 Linearly elastic and isotropic -- 5.3.2 Elastically non-linear and isotropic -- 5.3.3 Anisotropic and elastic -- 5.3.4 Elastic-plastic -- 5.3.5 Elastic-brittle -- 5.3.6 Viscoelastic materials -- 5.3.7 Viscoelastic phenomena -- 5.3.8 Temperature-dependent properties -- 5.4 Test types -- 5.4.1 Uniaxial compressive tests -- 5.4.2 Simple shear tests -- 5.4.3 Bend tests -- 5.4.4 Torsion tests -- 5.5 Testing products with a density gradient -- 5.5.1 Tensile or compression tests on EPS -- 5.5.2 Bend tests on EPS -- 5.6 Test equipment -- 5.6.1 Compressive impact -- 5.6.2 Tensile or shear impact -- 5.6.3 Creep -- 5.6.4 Compression set -- 5.6.5 Poisson's ratio -- 5.6.6 Humidity and temperature control -- References -- Chapter 6. Finite element modelling of foam deformation -- 6.1 Introduction -- 6.1.1 FEA packages -- 6.1.2 Static vs. dynamic FEA -- 6.1.3 FEA material models -- 6.2 Elastic foams -- 6.2.1 Curve fitting vs. strain energy functions -- 6.2.2 Strain energy function for rubbers -- 6.2.3 Ogden strain energy function for elastic foams -- 6.2.4 Validation of FEA: plane-strain indentation of flexible foams -- 6.3 Crushable foams -- 6.3.1 Yield surfaces -- 6.3.2 Crushable foam model in ABAQUS -- 6.3.3 Response of crushable foam model in simple deformations -- 6.3.4 Experimental data -- 6.3.5 Validation of FEA models -- 6.4 Dynamic FEA (explicit) -- 6.4.1 Computing issues -- 6.4.2 Simulation of foam compressive impact tests -- Summary -- References -- Chapter 7. Micromechanics of open-cell foams -- 7.1 Introduction -- 7.1.1 Concepts and approaches.

7.1.2 Observations of cell deformation -- 7.2 Edge geometry and stiffness -- 7.3 Regular polyhedral-cell models -- 7.3.1 Gibson and Ashby model -- 7.3.2 Kelvin cell model -- 7.4 Elastic moduli of the Kelvin foam -- 7.4.1 Uniform edge cross-sections -- 7.4.2 Non-uniform edge cross-sections -- 7.5 Compression of the Kelvin foam with uniform edges -- 7.5.1 History of modelling -- 7.5.2 Stress-strain response -- 7.5.3 Long range buckling -- 7.6 FEA model of wet Kelvin foam -- 7.6.1 [001] direction compression -- 7.6.2 [111] direction compression -- 7.7 Irregular foam models -- 7.8 Anisotropic cell shapes -- 7.9 Non-linear polymer response -- 7.10 Strain localisation -- 7.11 Modelling edge touching -- 7.12 Comparison with experiment -- References -- Chapter 8. Air flow in open-cell foams -- 8.1 Introduction -- 8.2 Air-flow measurement -- 8.2.1 Equipment -- 8.2.2 Data treatment -- 8.2.3 Data for PU foams with fully open cells -- 8.2.4 Data for compressed PU foams with fully open cells -- 8.2.5 Data for PU foams with partly open cells -- 8.3 Models for air-flow resistance -- 8.3.1 Gent-Rusch model -- 8.3.2 Gent-Rusch model with distorted faces -- 8.3.3 Fourie and Du Plessis model -- 8.3.4 CFD of Kelvin foam model -- 8.3.5 CFD of bead foam channels -- 8.3.6 CFD of the Weaire-Phelan model -- 8.4 Air flow during foam impact compression -- 8.4.1 Air pressure changes during compressive impacts -- 8.4.2 Air-flow modelling -- 8.5 Sound absorption in foams -- 8.6 Filters -- References -- Chapter 9. Seating case study -- 9.1 Introduction -- 9.2 Biomechanics of sitting in chairs -- 9.2.1 Seating posture and mannikins -- 9.2.2 Pressure sores and ischaemia -- 9.2.3 Measuring seating pressure distributions -- 9.2.4 Comparative deformation of the thigh and foam cushion -- 9.2.5 Moisture and heat transmission to the seat -- 9.2.6 Design of wheelchair seats.

9.2.7 Mattresses and sleep comfort -- 9.3 Car seats -- 9.3.1 Types of car seat -- 9.3.2 Comfort -- 9.3.3 Vibration transmission -- 9.3.4 Crash safety -- 9.4 Foam selection -- 9.4.1 Foam grades and the indentation force deflection test -- 9.4.2 FEA of IFD experiments -- 9.4.3 Comparison with experimental IFD pressure fields -- 9.4.4 Foam selection factors -- 9.4.5 High resilience PU foams -- 9.4.6 Ultra-low resilience PU foams -- 9.5 Seat design -- 9.5.1 Uniform uniaxial compression -- 9.5.2 Indentation with a rigid butt-form -- 9.5.3 Indentation with a compliant dummy -- 9.5.4 FEA of buttock and foam deformation -- 9.6 Other foam mechanical properties -- 9.6.1 Mechanical fatigue -- 9.6.2 Hydrolysis -- 9.6.3 Additives to provide fire resistance -- Summary -- References -- Chapter 10. Sport mat case study -- 10.1 Introduction -- 10.1.1 Mats used in sport -- 10.1.2 Foam materials -- 10.1.3 Head impacts -- 10.2 Modelling of impacts -- 10.2.1 Type of analysis -- 10.2.2 Hyperfoam model parameters for FEA -- 10.2.3 Static FEA model -- 10.2.4 Viscoelastic FEA model -- 10.3 Experimental impacts -- 10.3.1 Falling headform test -- 10.3.2 Effect of headform velocity -- 10.4 Fall mat design -- 10.5 Martial arts mats -- 10.5.1 Oblique foot impacts -- 10.5.2 FEA of mat deformation -- References -- Chapter 11. Micromechanics of closed-cell foams -- 11.1 Introduction -- 11.2 Observations of cell deformation -- 11.3 Material responses -- 11.3.1 The gas and polymer in parallel -- 11.3.2 Polymer response -- 11.3.3 Air response -- 11.4 Air-polymer interactions -- 11.4.1 Face bulging due to cell pressure differentials -- 11.4.2 Foam diffusivity -- 11.4.3 Heat transfer from cell air to faces -- 11.5 Kelvin foam model for elastic moduli -- 11.5.1 Young's modulus -- 11.5.2 Bulk modulus -- 11.5.3 Young's modulus assuming wrinkled faces.

11.6 Regular foam models for high strain compression -- 11.6.1 Introduction -- 11.6.2 Gibson-Ashby models -- 11.6.3 Kelvin foam elastic-plastic model -- 11.6.4 Wierzibicki plasticity model -- 11.6.5 Dynamic FEA of Kelvin foam model -- 11.6.6 Modelling unloading -- 11.7 Irregular foam models -- 11.8 Bead foams -- 11.8.1 Deformation mechanisms -- 11.8.2 Models for compression -- 11.9 Discussion -- References -- Chapter 12. Product packaging case study -- 12.1 Introduction -- 12.2 Simple drops with the box parallel to the floor -- 12.2.1 Drop heights and fragility factors -- 12.2.2 Cushion curve tests -- 12.2.3 Cushioning provided by the cardboard box -- 12.2.4 Design using cushion curves -- 12.2.5 Calculating cushion curves from stress-strain responses -- 12.2.6 Cushion curves for specific stress-strain responses -- 12.2.7 Energy absorption diagrams and foam selection -- 12.3 Design of EPS mouldings -- 12.3.1 Moulding geometry -- 12.3.2 Stupak and Donovan's model for tapered ribs -- 12.3.3 FEA of truncated pyramids -- 12.3.4 Design rules for ribs -- 12.4 Other factors in packaging design -- 12.4.1 Foam creep during storage -- 12.4.2 Package vibration in transit -- 12.4.3 Temperature -- 12.4.4 Multiple impacts -- 12.5 In-package tests of shock absorption -- 12.5.1 Introduction -- 12.5.2 Corner and edge impacts -- 12.5.3 FEA of in-box PE foam packaging -- Summary -- References -- Chapter 13. Running shoe case study -- 13.1 Introduction -- 13.1.1 Information sources -- 13.1.2 Foam shoe components -- 13.1.3 Patented features in shoes -- 13.2 Foam selection and properties -- 13.2.1 Material selection -- 13.2.2 Microstructure and processing of EVA foam -- 13.2.3 Alternatives to EVA foam -- 13.2.4 Grades of foam -- 13.3 Running biomechanics -- 13.3.1 Midsole foam pressure distribution -- 13.3.2 Foot strike forces -- 13.3.3 Foam flexure and heel stability.

13.3.4 The effect of the shoe on running style.