Biocompatible and biodegradable polylactide
(PLA) composites with
supertough mechanical property and sufficient flame retardancy were
fabricated by employing a facile approach involving reactive blending
of PLA and ethylene-acrylic ester-glycidyl methacrylate terpolymer
(EGMA), with the addition of aluminum hypophosphite (AHP) as an effective
flame retardant. In consideration of the balance between mechanical
property and flame retardancy, the optimal formula was taking a PLA/EGMA
80/20 blend (supertough STPLA) as the matrix and adding 20 wt % of
AHP (relative to the mass of STPLA) as the flame retardant, coded
as STPLA/20AHP. The mechanical property test showed that for STPLA/20AHP
the elongation at break was increased by about 22 times and the notched
Izod impact strength was enhanced by approximately 11 times as compared
to those for neat PLA. The flame-retardant property test showed that
for STPLA/20AHP the limiting oxygen index value reached 26.6% and
the UL-94 V0 rating test was passed. Thermogravimetric analysis, microscale
combustion calorimetry, and cone calorimeter were further applied
to reveal the thermal stability and combustion behaviors of STPLA/
x
AHP, respectively, where
x
indicated the
mass content of AHP in percentage. The phase separation morphology,
dispersion of AHP particles in STPLA matrix, and fracture surfaces
and char residues after flame burning were examined by phase contrast
optical microscopy and scanning electron microscopy, respectively,
which helped comprehend the results obtained from the mechanical property
and flame retardancy tests. The supertough STPLA/
x
AHP, with sufficient flame retardancy as prepared in this work, could
have a potential for engineering applications.