An accelerated hydrothermal degrading test was designed in order to analyse the synergic effect of water and temperature on PLA/sisal biocomposites with and without coupling agent. As well, the physico-chemical properties of biocomposites were monitored along the hydrothermal test by means of Scanning Electron Microscopy, Size Exclusion Chromatography and Differential Scanning Calorimetry. The addition of fibre induced higher water absorption capability and promoted physical degradation, as observed in the surface topography. During the processing of biocomposites and throughout the hydrothermal ageing, a reduction of molecular weight due to chain scission was found. As a consequence, a faster formation of crystalline domains in the PLA matrix occurred the higher the amount of fibre was, which acted as a nucleating agent. Higher crystallinity was considered as a barrier against the advance of penetrant and a reduction in the diffusion coefficient was shown. The addition of coupling agent presented a different influence depending on the composition, showing an inflection point around 20% of sisal fibre.
|Pages (from-to)||212 - 222|
|Number of pages||11|
|Journal||Polymer Degradation and Stability|
|Early online date||17 Jun 2014|
|Publication status||Published - Oct 2014|
Bibliographical noteThe authors would like to acknowledge the Spanish Ministry of Economy and Competitiveness, through the Research Project ENE2011-28735-C02-01. Generalitat Valenciana is thanked for the APOSTD/2013/054 and ACOMP/2013/143 programs. Universitat Politecnica de Valencia is thanked for the concession of a pre-doctoral grant to Oscar Gil Castell. O.G.C. wants to warmly dedicate this paper to Marita and Vicente for their endless and priceless support, and to Maria, his beloved pillar.
- Polylactide (PLA)
- Natural fibres
- Hydrothermal degradation
- Water absorption