Ivan Chodak
Polymer Institute SAS, Slovakia
Title: Effect of biodegradation on physical properties of PLA-based blends
Biography
Biography: Ivan Chodak
Abstract
Biodegradable plastics undergo to substantial changes due to degradation by enzymes produced by various bacteria. From application point of view, modification of physical properties is important, occuring even when the testing specimens are apparently unchanged.
Degradation in compost of polylactic acid (PLA), PLA with a plasticizer triacetin (TAC), and a mixture of PLA / polyhydroxybutyrate (PHB) / TAC proceeded at temperature 58 oC up to 16 days and the biodegradation degree was determined by measuring the content of evolved carbon. The degradation rate was found to vary a little for the three samples.
While the biodegradation tests were performed almost to complete biodegradation of the materials to carbon dioxide and water, physical properties could be measured only for the first 8 days and in some cases up to 16 days when it was possible to separate the material from the compost. At longer periods the materials have been disintegrated to small fragments and separation of the sample from compost was impossible.
Number of testing methods was applied. Molecular weight and molecular weight distribution was determined by GPC, supported by measuring the viscosity by rheology. Structure of the materials were estimated from changes in Tg and crystallinity. Mechanical properties of samples and the data were compared with information obtained from dynamic mechanical analysis (DMTA).
The conclusions have been made regarding the effect of TAC and PHB presence on the biodegradation of PLA, and related changes concerning the structure / mechanical relations.
Acknowledgement: The supported from projects VEGA 1/0570/17, APVV 15-0741 is appreciated.