In this study, we utilized in situ
nanofibrillation of thermoplastic
polyester ether elastomer (TPEE) within a high-density polyethylene
(HDPE) matrix to enhance the rheological properties, foamability,
and mechanical characteristics of the HDPE nanocomposite at both room
and subzero temperatures. Due to the inherent polarity differences
between these two components, TPEE is thermodynamically incompatible
with the nonpolar HDPE. To address this compatibility issue, we employed
a compatibilizer, styrene/ethylene-butylene/styrene copolymer-grafted
maleic anhydride (SEBS-g-MA), to reduce the interfacial
tension between the two blend components. In the initial step, we
prepared a 10% masterbatch of HDPE/TPEE with and without the compatibilizer
using a twin-screw extruder. Subsequently, we processed the 10% masterbatch
further through spun bonding to create fiber-in-fiber composites.
Scanning electron microscopy (SEM) analysis revealed a significant
reduction in the spherical size of HDPE/TPEE particles following the
inclusion of SEBS-g-MA, as well as a much smaller
TPEE nanofiber size (approximately 60–70 nm for 5% TPEE). Moreover,
extensional rheological testing revealed a notable enhancement in
extensional rheological properties, with strain-hardening behavior
being more pronounced in the compatibilized nanofibrillar composites
compared to the noncompatibilized ones. SEM images of the foam structures
depicted substantial improvement in the foamability of HDPE in terms
of the cell size and density following the nanofibrillation process
and the use of the compatibilizer. Ultimately, the in situ rubber
fibrillation and enhancement of HDPE and TPEE interface using a compatibilizer
led to increasing the HDPE ductility at room and subzero temperatures
while maintaining its stiffness.