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6596609 
Journal Article 
Tailoring viscoelastic and mechanical properties of the foamed blends of EVA and various ethylene-styrene interpolymers 
Liu, IC; Tsiang, RCC; , 
2003 
1 
Polymer Composites
ISSN: 0272-8397 
SOC PLASTICS ENG INC 
BROOKFIELD 
24 
3 
304-313 
English 
WOS:000183848600002 
Foamed materials (EVA/ESI) have been:prepared from blends of ethylene-vinyl acetate copolymer (EVA) and ethylene-styrene interpolymers (ESI) in the presence of various amounts of dicumyl peroxide (DCP). Four ESIs of different compositions were employed in this study; their styrene contents ranged from 30 to 73 wt% and their T-g ranged from -2 to 33degreesC. It has been found that microcellular morphology, degree of crosslinking and, expansion ratio were strongly,affected by the, DCP concentration and the type of ESI employed., A minimum degree of crosslinking was required for making good foams and the same degree of crosslinking could be achieved by employing a smaller amount of DCP for an.,EVA/ESI blend having a higher styrene content. In contrast to other EVA blends, such as EVA/LDPE, these EVA/ESI blends exhibited no existence of any optimum DCP concentration, and the alpha glass transition temperatures of the foams varied with the ESI type, covering a wide span from. 0degreesC to 37degreesC. Therefore, it was possible to tailor the T-g of an EVA/ ESI blend by choosing an appropriate type of ESI. Furthermore, by correctly tailoring the T-g, the EVA/ESI foam could. be made. into a rubbery material with a custom-designed damping factor. Tensile strength and modulus of the EVA/ESI foams increased generally with an increase in the styrene content, with the exception that ESIs with very low styrene content will confer on the blend a high modulus at small strain and a large elongation at break..