The results showed clearly the formation of covalent
bonds between MAgPLA and PVOH during the reactive
extrusion which decreases the phase separation in the PLA/PVOH
blends [9]. To further evidence the role of MAgPLA as reactive
compatibilizer for CA blends, two PVOH-rich blends with the same
pCA/pPVOH composition were prepared adding 10 phr of MAgPLA
or neat (non functionilized) PLA (Entries 7 and 8 on Table 3,
respectively). The results showed that the compatibilized blend
exhibited a significantly higher Young modulus and a reduction of
the strain at break in comparison to the blend including neat PLA.
Another evidence on the effect of MAgPLA on the physical properties
can be seen from the data in Table 3 where increasing the
content of PVOH in the uncompatibilized CA/PVOH blends tends to
the mechanical properties of PVOH alone whereas in the case of
compatibilized blend even with higher PVOH content the mechanical
properties did not tend to those of PVOH alone (Table 3,
Entries 6, 9 and 10). Accordingly, the increase in stiffness observed
for all compatibilized blends could be reasonably attributed to the
action of MAgPLA, which improved the interfacial adhesion. These
observations are consistent with the establishment of a cocontinuous
morphology while increasing the PVOH content in the
composition and when MAgPLA was considered as compatibilizer.
Further investigation of the morphology has thus been carried out
by scanning electron microscopy and will be discussed in a next
section.