The notched Izod impact strength results for the tested PLA/talc compositions are shown in Fig. 8. The impact strength of the PLA dropped with the presence of talc
particles, which related to the reduction of the elongation at break and the improved
degree of crystallinity. A maximum decrement of 16 % was found when 30 lm talc
was added at 10 wt%. This reduction was caused by (1) the poor interfacial adhesion
between PLA and talc particles; and (2) the brittle nature of both PLA and talc. The
micrograph of the composite in Fig. 9 displays the typical characteristics of an
incompatible composite. Some pulled-out particles and interfacial voids were also
found in all talc particles. These defects allowed the crack to propagate more easily
and caused embrittlement of the PLA.