Polyamide 11/poly(hydroxy amino ether) blends: Influence of the blend composition and morphology on the barrier and mechanical properties
Résumé
A series of PA11/PHAE blends was prepared by melt mixing across the full composition range. Films were obtained for each composition by an extrusion-cast process keeping the same processing conditions. The blends exhibited a two phase morphology. PHAE-rich nodules surrounded by the PA11-rich matrix were observed for PA11 contents higher than 50 wt% in the blends. For lower PA11 weight amounts, PA11 became the dispersed phase and appeared as long fibrillar domains lying in the plane of the film. PA11/PHAE interactions were discussed from DSC and DMA analyses. The effects of the blend composition and morphology on mechanical properties in the linear range and on hydrogen barrier properties were investigated. Hydrogen permeability decreased with increasing amount of PHAE in the blends. A confrontation between the experimental permeability values and the theoretical ones calculated by taking account of the specific properties and morphology of the PA11- and PHAE-rich phases was carried out. In the films series under study, the improvement of hydrogen barrier properties was mainly related to the blend composition whereas a significant effect of the blend morphology was observed on mechanical properties in the rubbery state.