Toward Excellent Barrier Performance for Semicrystalline Polyethylene Terephthalate via Controlling Crystallinity and Rigid Amorphous Fraction

Abstract

Polymer-based barrier materials are crucial for several applications, from food packaging to electronics sealing. However, the inferior intrinsic barrier performance greatly restricts their applications, which is urgently necessary for further enhancement. In this work, we proposed a strategy named modified dynamic pressure engineering to regulate the nature of crystalline and amorphous regions of semicrystalline polyethylene terephthalate for enhancing its barrier performance. The oxygen permeability coefficient (OPC) is reduced to 5.94 × 10–15 cm3·cm/cm2·s·Pa, with a high corresponding barrier improvement factor (BIF) of 3.85. The promotion of barrier performance originates from the promotion of crystallinity, densified chain packing, suppressed segmental motion, and the lower volume fraction of rigid amorphous fraction (RAF). Meanwhile, it is the first time that the OPC of the RAF has been quantitatively investigated, confirming that the OPC of RAF is much higher than that of mobile amorphous region, and this work can provide a meaningful guideline for fabricating high-barrier materials.