Structure evolution of polyamide (11)’s crystalline phase under uniaxial stretching and increasing temperature

Abstract

Thermal processing of polyamide influences the internal crystalline structure and thereafter the post product mechanical performance. In this article, the crystalline transition of polyamide-11 (PA11) plate under uniaxial stretching and increasing temperature was investigated systematically using in-situ synchrotron X-ray technique. It was discovered that the lamellar slippage, fragmentation and recrystallization occurred in sequence under increasing temperature. In detail, the crystal of PA11 plate was stretched with a transition from triclinic α-form to mesomorphic phase at 25 °C. For the thermally activated γ-form crystals, crystal transition was inhibited when temperature was increased up to 160 °C. The melt-recrystallization was inclined to take place at large tensile strains. This work enhances the research significance of the thermal processing of polyamide and provides a theoretical method to improve the high performance of polyamide products.