Effect of Organoclay on Morphology, Barrier Properties, and Aerobic Biodegradation of Poly(Lactic Acid)/Natural Rubber Nanocomposites

ABSTRACT In this work, the correlation of morphology, water vapor permeability (WVP), and organoclay (Cloisite 30B, C30B) concentration on the aerobic biodegradation of poly(lactic acid) (PLA)/natural rubber (NR)/C30B was investigated. The results of scanning electron microscopy, X‐ray diffraction analysis, rheological and dynamic mechanical analyses showed a reduction in the size of rubber droplets (from 1.62 to 0.75 μm), the entry of polymer into the interlayer space of C30B, an increase in viscosity and elasticity, and improved compatibility between the two phases in the nanocomposite. Using NR increased the WVP of PLA (~9%), but the addition of C30B up to 5 phr reduced it by ~85% due to the creation of more effective tortuous paths. After 26 weeks of soil burial, the PLA/NR blend degraded slightly more than PLA due to its higher WVP. The degradation in nanocomposites was affected by the clay content. So that the use of 1 and 3 phr C30B increased biodegradability due to its dominant catalytic effect on hydrolysis, and the addition of 5 phr reduced the overall degradation rate and the biodeterioration pattern changed, which was attributed to the dominant barrier effect of C30B.