Steam-Chest Molding of Expanded Polypropylene Foams. 2. Mechanism of Interbead Bonding

Expanded polypropylene (EPP) bead foams were processed using steam-chest molding. Interbead bonds formed during processing and was characterized by observing both the product surface and the fracture surfaces using scanning electron microscopy (SEM) and by measuring the tensile properties of specimens. It was found that both the degree of interbead bonding and the tensile strength had a direct relationship to the steam pressure/temperature and that high steam temperature enhanced the crystallization behavior of EPP beads during the cooling process. A formation mechanism of interbead bonding during processing was proposed based on the crystal melting behaviors, as discussed in the first article of this series (Zhai et al. Ind. Eng. Chem. Res. 2010, 49, 9822). Possible parameters influencing the formation of interbead bonding, namely, steam temperature/pressure and bead foam expansion ratio, were investigated in this study. The effect of postannealing of the EPP products on the shrinkage and crystallinity o...

[1]  Chul B. Park,et al.  Steam-Chest Molding of Expanded Polypropylene Foams. 1. DSC Simulation of Bead Foam Processing , 2010 .

[2]  Philippe Viot,et al.  Hydrostatic compression on polypropylene foam , 2009 .

[3]  Philippe Viot,et al.  Polypropylene foam behaviour under dynamic loadings : Strain rate, density and microstructure effects , 2009 .

[4]  M. Ohshima,et al.  Numerical simulation of a polypropylene foam bead expansion process , 2008 .

[5]  N. J. Mills,et al.  Properties of bonded-polypropylene-bead foams: data and modelling , 2007 .

[6]  Nancy A. Winfree,et al.  Strain-rate effects on elastic and early cell-collapse responses of a polystyrene foam , 2005 .

[7]  M. Champagne,et al.  Impact-Compression-Morphology Relationship in Polyolefin Foams , 2005 .

[8]  I. Beverte.  Deformation of Polypropylene Foam Neopolen® P in Compression , 2004 .

[9]  Qian Sun,et al.  Modeling of Bond Formation Between Polymer Filaments in the Fused Deposition Modeling Process , 2004 .

[10]  R. Overfelt,et al.  Investigation of the performance of an expandable polystyrene injector for use in the lost-foam casting process , 2003 .

[11]  S. Shivkumar,et al.  Bead fusion in polystyrene foams , 2003 .

[12]  Giuseppe Sala,et al.  Deformation mechanisms and energy absorption of polystyrene foams for protective helmets , 2002 .

[13]  G. Belingardi,et al.  Characterization of polymeric structural foams under compressive impact loading by means of energy-absorption diagram , 2001 .

[14]  N. J. Mills,et al.  Shear and compressive impact of polypropylene bead foam , 1999 .

[15]  N. J. Mills.  Time dependence of the compressive response of polypropylene bead foam , 1997 .

[16]  N. J. Mills,et al.  The Effect of Water Immersion on the Mechanical Properties of Polystyrene Bead Foam Used in Soft Shell Cycle Helmets , 1994 .

[17]  P. R. Stupak,et al.  The Effect of Bead Fusion on the Energy Absorption of Polystyrene Foam. Part I: Fracture Toughness , 1991 .

[18]  P. R. Stupak,et al.  The Effect of Bead Fusion on the Energy Absorption of Polystyrene Foam. Part II: Energy Absorption , 1991 .