Effect of NR on the hydrolytic degradation of PLA

The hydrolytic degradation of PLA and PLA/NR blends in deionized water at 58 °C was studied to reveal the effect of NR on the hydrolysis of PLA. The contact angle and water absorption, the evolution of average molecular weight, mass, morphology and thermal property were investigated. Results show that NR can enhance the hydrophobility of the surface of PLA but it does not cause a decrease of water absorption in the bulk of PLA. On the contrary, the water absorption increases with increasing NR content. The hydrolysis occurs in entire bulk of the specimens not confined in the surface, exhibiting bulk erosion degradation mechanism. NR has no observable effect on the hydrolysis of PLA, which would be beneficial for the biodegradation of PLA toughened by NR. In addition, through the investigation of thermal property, NR has been found to show a hindering effect on the PLA crystalline.