Polymer Institute SAS, Slovakia
IVAN CHODAK Affiliation : Polymer Institute of the Slovak Academy of Sciences Job status : Senior scientist Department of Composite Materials Full Professor of Macromolecular Science, Slovak Technical University Education and Professional carreer : 1960 - 1965 Slovak Technical University, Faculty of Chemical Technology, Bratislava 1965 - 1970 Matador, rubber factory, Bratislava 1970 - Polymer Institute, Slovak Acad. Aci., BRATISLAVA 1970 - 1973 PhD Student 1975 PhD 1973 - 1981 Scientist 1982 - 2010 Head of Department of Composite Thermoplastics 1989 – 1990 Deputy Director 1997 DSc 2000 Associated Professor of Macromolecular Science 2005-2009 Member of Presidium of the Slovak Academy of Sciences 2006 Full professor of Macromolecular Science LEAVES OF ABSENCE 1981 - 1982 One-year sabbatical leave at Clarkson University, Potsdam, NY 1983 - 1997 Several short-term stays (up to two months), e.g. Techn. Univ. Eindhoven, Univ. Quebec Trois Rivieres, ENSAM Paris, CNR Arco Felice, etc. AWARDS 1989 - Slovak National Prize for excellent results in polypropylene modification (member of a team of 5 scientists) 1993 - Silver Medal of Dionýz Štúr for "A Significant Contribution to a Development of Natural Sciences" 2003 – Medal of Slovak Academy of Sciences for Achievements in Science 2012 – Award of the Minister of Education of Slovak Republic as the Scientific Personality of the Year 2014 – Gold Medal of the Slovak Academy of Sciences Scientific interests Multiphase systems with a modified polymeric matrix, synthesis and properties.
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.