Nanoclay effects on the degradation process and product patterns of polylactide

作者：Roy Prasun K; Hakkarainen Minna; Albertsson Ann Christine^*

来源：Polymer Degradation and Stability, 2012, 97(8): 1254-1260.

DOI：10.1016/j.polymdegradstab.2012.05.032

• Polylactide
• Polyester
• Nanoclay
• Degradation
• Hydrolysis
• Degradation products

The addition of montmorillonite (MMT) nanoclays shifted the degradation product patterns of polylactide towards shorter lactic acid oligomers as compared to the product patterns of plain polylactide and halloysite modified polylactide hydrolysed under same conditions. The addition of the two MMT sheet type nanoclays led to substantial improvement in the barrier properties of polylactide, which was attributed to the inherent restriction offered by the inorganic filler towards the movement of gases through the film. This could be connected to the observed change in the degradation product patterns as the formed degradation products, especially the longer oligomers, could be partially trapped inside the films leading to catalytic effect, higher mass loss at later stages of hydrolysis as well as release of shorter lactic acid oligomers into the ageing water. The nanocomposites generally exhibited higher contact angles indicating increased hydrophobicity. However, hyperbranched polyesters additives were found to be preferentially present at the surface of the films which led to increased surface hydrophilicity for these materials. The hydrolytic degradation was performed at 60 degrees C for up to 12 weeks and the process was monitored by mass loss measurements, molar mass changes and calorimetric studies. The water-soluble degradation products were examined by electrospray ionization-mass spectrometry (ESI-MS).

• 出版日期2012-8