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.