Rheo-Raman spectroscopic study of plasticity and elasticity transformation in poly(ether-block-amide) thermoplastic elastomers

The microscopic deformation behavior of polyamide (PA) elastomers (PAEs) with various PA contents has been investigated by rheo-Raman spectroscopy. The PAEs with relatively high PA content show a uniaxial molecular orientation and the stretching load is isotropically applied on the crystalline chains, similar to typical semi-crystalline polymers. Conversely, the crystalline chains of the PAEs with relatively low PA content show a biaxial molecular orientation up to the highly strained region. Moreover, the stretching load is anisotropically applied on the crystalline chains located in the equatorial region of the spherulites. The elasticity of the PAEs with relatively low PA content is ascribed to the affine-like deformation of the spherulitic structure owing to the existence of soft interlamellar layers.