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Poly(lactic) acid, PLA, is a compostable thermoplastic which degrades fast under composting conditions of microorganisms, high humidity and temperatures. However, PLA degrades slowly below its glass transition temperature and in low humidity, hence, when used as short-shelf life product containers and not disposed to composting systems, PLA may cause environmental pollution. Therefore, when not disposed to proper waste management systems, the effect of long incubation time at room temperature on mechanical and thermal properties of PLA is the main concern of this study. To determine the effect of room temperature on semi-crystalline PLA degradation at a low humidity percentage, PLA films (PLA2) were kept at room temperature for 5 years at 40±10% humidity. Some PLA films (PLA3) were pre-treated at 55°C under dry conditions for 1 year and then kept at room temperature for 4 years. Influence of incubation time and temperature on PLA degradation was evaluated by mechanical, thermal analyses and by Fourier-Transformation Infrared Spectroscopy Analysis (FTIR) and compared with the initial PLA samples (PLA1). Mainly mechanical properties of PLA were affected by incubation temperature and time since 68% tensile strength loss was observed in PLA3 samples which were pre-treated at 55ºC and 34% decrease in tensile strength was observed in PLA2 samples. Thermal behaviour of PLA was also influenced by incubation time and temperature as degree of crystallinity decreased 2 and 5% in PLA2 and PLA3 samples, respectively. Deformation of CH bonds and amorphous phase degradation were revealed by FTIR analyses in PLA2 and PLA3 samples.
PAPER REVISED: 2018-12-28
PAPER ACCEPTED: 2019-01-05
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THERMAL SCIENCE YEAR 2019, VOLUME 23, ISSUE Supplement 1, PAGES [S383 - S390]
  1. Fambri, L. et. al., Biodegradable Polymers, in: Integrated Biomaterials Science (Ed. R.Barbucci), Kluwer Academic/Plenum Publishers, New York, USA, 2002, pp. 119-187.
  2. Tharanathan, R., Biodegradable films and composite coatings: past, present and future, Trends Food Sci. Technol., 14, (2003), 3, pp. 71-78.
  3. Rodríguez-núñez, J.R., et. al., Composite Materials Based on PLA and its Applications, in: Food Packaging in Composite Materials for Food Packaging, (Ed. G. Cirillo) Scrivener Publishing LLC, 2018; pp. 355-400.
  4. Thompson, R.C., et. al., Our plastic age, Philos. Trans. R. Soc. Lond. B. Biol. Sci., 364 (2009), 1526, pp. 1973-1976.
  5. Oehlmann, J., et al., A critical analysis of the biological impacts of plasticizers on wildlife. Philos. Trans. R. Soc. B Biol. Sci., 364 (2009), 1526, pp. 2047-2062.
  6. Stefanoviĉ, G.M., et. al., Pollution data tracking in the western Balkan countries: A state-of-the-art review, Therm. Sci., 12 (2009), 4, pp. 105-112.
  7. Kalina, J., Fossil fuel savings, carbon emission reduction and economic attractiveness of medium-scale integrated biomass gasification combined cycle co-generation plants. Therm. Sci., 16 (2012), 4, pp. 827-848.
  8. Castro-Aguirre, et. al., Poly ( lactic acid ) - Mass Production , Processing, Industrial Applications and End of Life, Adv. Drug Deliv. Rev., 107 (2016), pp.333-366.
  9. Vink, E.T.H., et. al., The sustainability of NatureWorks polylactide polymers and Ingeo polylactide fibers: an update of the future, Macromol. Biosci., 4 (2004), 6, pp. 551-564.
  10. Auras, R., et al., An overview of polylactides as packaging materials, Macromol. Biosci., 4 (2004), 9, pp. 835-864.
  11. Lunt, J., Large-scale production, properties and commercial applications of polylactic acid polymers, Polym. Degrad. Stab., 59 (1998), pp.145-152.
  12. Kale, G., et. al. Comparison of the degradability of poly (lactide ) packages in composting and ambient exposure conditions, Packag. Technol. Sci., 20, (2007), pp. 49-70.
  13. Agarwal, M., et. al., Characterization of the degradation of polylactic acid polymer in a solid substrate environment, Biotechnol. Prog., 14 (1998), 3, pp. 517-526.
  14. Sangwan, P., Wu, D.-Y, New insights into polylactide biodegradation from molecular ecological techniques, Macromol. Biosci., 8, (2008), 4, pp. 304-15.
  15. Karamanlioglu, M., Robson, G.D., The influence of biotic and abiotic factors on the rate of degradation of poly(lactic) acid (PLA) coupons buried in compost and soil, Polym. Degrad. Stab., 98 (2013), pp. 2063-2071.
  16. Tomita, K., et. al., Degradation of poly (L-lactic acid) by a newly isolated thermophile, Polym. Degrad. Stab., 84, (2004), pp. 433-438.
  17. Park, K.I., Xanthos, M., A study on the degradation of polylactic acid in the presence of phosphonium ionic liquids, Polym. Degrad. Stab., 94 (2009), pp. 834-844.
  18. Karamanlioglu, M., et. al., Isolation and characterisation of fungal communities associated with degradation and growth on the surface of poly(lactic) acid (PLA) in soil and compost, Int. Biodeterior. Biodegradation, 95 (2014), Part B, pp. 301-310.
  19. Jarerat, A.; Tokiwa, Y., Degradation of Poly(L-lactide) by a Fungus, Macromol. Biosci., 1 (2001), pp. 136-140.
  20. Watanabe, M., et. al., Study on enzymatic hydrolysis of polylactic acid by endogenous depolymerization model, Macromol. Theory Simulations, 16 (2007), pp. 619-626.
  21. Henton, D.E. et. al., Polylactic Acid Technology, in Natural Fibers, Biopolymers, and Biocomposites, (Eds. A.K. Mohanty, et. al.), CRC Press, Boca Raton, FL, USA, 2005, pp. 527-578.
  22. Fukushima, K. et. al., Biodegradation of poly(lactic acid) and its nanocomposites, Polym. Degrad. Stab., 94 (2009), pp. 1646-1655.
  23. Kolstad, J.J. et. al., Assessment of anaerobic degradation of Ingeo polylactides under accelerated landfill conditions, Polym. Degrad. Stab., 97 (2012), 7, pp. 1131-1141.
  24. Urayama, H. et. al., Properties and Biodegradability of Polymer Blends of Poly (L‐lactide)s with Different Optical Purity of the Lactate Units, Macromol. Mater. Eng., 287 (2002), pp. 116-121.
  25. Karamanlioglu, M., et. al., Abiotic and biotic environmental degradation of the bioplastic polymer poly(lactic acid): A review, Polym. Degrad. Stab., 137 (2007), pp. 122-130.
  26. Quynh, T.M. et. al., Stereocomplexation of low molecular weight poly(L-lactic acid) and high molecular weight poly(D-lactic acid), radiation crosslinking PLLA/PDLA stereocomplexes and their characterization, Radiat. Phys. Chem., 83 (2013) pp. 105-110.
  27. Rhim, B.J., et. al., Increase in water resistance of paperboard by coating with poly(lactide ), Packag. Technol. Sci., 20 (2007), pp. 393-402.
  28. Fischer, E.W. et. al., Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical reactions, Kolloid-Zeitschrift und Zeitschrift für Polym. 251 (1973), 980-990.
  29. Alkan, Ü. et al., Electrical and Mechanical Properties of LDPE/PANI Composites, J. Nanoelectron. Optoelectron., 11(2016), 4, pp. 343-348.
  30. Vey, E. et. al., Degradation kinetics of poly ( lactic-co-glycolic ) acid block copolymer cast fi lms in phosphate buffer solution as revealed by infrared and Raman spectroscopies, Polym. Degrad. Stab., 96 (2011), 10, pp. 1882-1889.
  31. Ho, K.G., Pometto, A.L., Effects of Electron-Beam Irradiation and Ultraviolet Light (365 nm) on Polylactic Acid Plastic Films, J. Environ. Polym. Degrad., 7 (1999), pp. 93-100.
  32. Weir, N. A., et. al., Degradation of poly-L-lactide. Part 1: in vitro and in vivo physiological temperature degradation, Proc. Inst. Mech. Eng. H., 218 (2004), 5, pp. 307-319.
  33. Vert, M. et. al., New insights on the degradation of bioresorbable polymeric devices based on lactic and glycolic acids, Clin. Mater., 10 (1992) pp. 3-8.
  34. Fukushima, K. et. al., Biotic degradation of poly(dl-lactide) based nanocomposites, Polym. Degrad. Stab., 97 (2012), 8, pp.1278-1284.
  35. Cao, X. et. al., DSC study of biodegradable poly(lactic acid ) and poly(hydroxy ester ether ) blends, Thermochim. Acta, 406 (2003), pp. 115-127.

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