Influence of clay percentage on the technical properties of montmorillonite/polylactic acid nanocomposites

The proliferation and misuse of plastics have become an environmental problem since the late 20th century. For this reason, providing solutions that combine the efficiency of plastics with respect for the environment is necessary. In the last years, the industry sector is investing in biopolymers, such as polylactic acid (PLA), which meet all the environmental requirements for degradation and provide many technical characteristics of conventional polymers. These technical characteristics, in addition, can be improved using clay minerals (montmorillonite; Mt) as reinforcing agents in the manufacture of nanocomposites. In this work, nanocomposites of PLA, reinforced with Mt. (at different clay loadings), were manufactured, and the improvement of some of its properties (thermal and mechanical) were evaluated. The results show an increase in thermal stability and Young's modulus of the materials, all related to an increase in structural order, both at the crystalline level and the structure formed by the clay nanoplatelets and the polymer lamellae. •The Mt. in Mt./PLA increases the melting temperature and crystallinity of the CPN.•The arrangement of Mt. and PLA affects the yield strain and embrittles the CPN.•Mt. induces higher order degree at the unit cell scale and polymer lamellae scale.•The nanocomposite phases in the CPN arrange according to a ‘skin-core’ model.