Microscopic origin of elastic and plastic deformation in poly(ether-block-amide) elastomers under various conditions

Abstract

Microscopic deformation behavior of polyamide (PA) elastomers (PAE) with various PA contents has been elucidated using various structural analyses including in situ infrared spectroscopy under cycle tests. Below the glass transition temperature (Tg), the stress-strain curves showed an obvious yielding point irrespective of the soft-segment content. The plastic deformation under tension is interpreted by irreversible morphological transformation observed in semi-crystalline polymers, such as the collapse of the spherulites and the fragmentation of the lamellar crystals. Above Tg, whereas the stress-strain curve is dominated by the temperature distance from Tg, PAE with higher soft-segment contents shows more elastic deformation in its supermolecular structure, which is essentially reversible up to the highly-strained region. The microscopic origin of high tunability for the elasticity of PAE is assigned to the mobility of interlamellar amorphous chains dominated by Tg.