Thermal and bio-disintegration properties of poly(lactic acid)/natural rubber/organoclay nanocomposites

• PLA/NR/MMT nanocomposites were prepared by melt blending.
• NR acts as a nucleating agent for the PLA matrix.
• The location of the MMT at the polymers interface inhibits this nucleating effect.
• The organoclays decrease the disintegration rate in compost of the polymer blend.

The crystallisation behaviour of a poly(lactic acid) (PLA)/natural rubber (NR) blend compatibilised through the addition of organoclays located at the interface between both polymers was evaluated by differential scanning calorimetry (DSC), rheological and wide angle X-ray diffraction (WAXD) measurements. NR acted as a nucleating agent for the PLA matrix, leading to a decrease of PLA cold crystallisation temperature during dynamic DSC measurements and an increase of the crystallisation rate followed by rheological measurements during isothermal crystallisation. Nevertheless, this effect was suppressed when adding 3 wt.% of organoclays due to the particular morphology of the nanocomposites. Moreover, the organoclays increased the thermal degradation temperature of the PLA/NR blend and delayed its disintegration in compost, without affecting the disintegration percentage after one month of experiment.