Introduction
The contribution of petroleum-based polymers to environmental
problems and poor air quality has recently created an
increased interest in bio-based polymers, with the use of renewable
resources being particular advantageous [1]. Poly(lactic acid) (PLA)
is a bio-based thermoplastic polyester that is obtained from
renewable resources such as cornstarch or sugarcane [2], and
which offers an attractive alternative to conventional polymers due
to its excellent biocompatibility, high tensile strength and high
modulus. However, PLA also possesses a high brittleness that tends
to limit its practical application [3]. As a result, many attempts have
been made at improving the toughness of PLA while maintaining its
bio-based characteristics [4e10]. Among these, it is natural rubber
(NR) that has been the most widely studied for use as an impact
modifier [4e8], as it is derived from natural resources such as the
Hevea brasiliensis tree