Abstract

Blends of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) with various contents (0, 5, 10, 15, 20 and 30 weight %) and with different molecular weights (M¯w = 1000, 4000 and 6000 g/mol), called respectively PEG1, PEG2, and PEG3 were prepared by melt blending. Since glass transition temperature (Tg), T? and loss factor (tan ?) are relevant indicators of polymer chain mobility, plasticization has been studied by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). Low molecular weight (LMW) PEG enable increased miscibility with PLA and more efficient reduction of glass transition temperature (Tg) for concentrations of PEG less than 20%. This effect is not only enhanced by the LMW but also by increasing its content up to 20%. As expected, both T? and Tg decrease when increasing PEG molar mass and content up to 20%, which demonstrates the effectiveness of PEG to act as a plasticizer of PLA.

References

[1] R. E. Drumright, P.R. Gruber, and D. E. Henton, “Polylactic acid technology,” Advanced materials, vol. 12, no. 23, pp. 1841–1846, 2000.
[2] D. Garlotta, “A literature review of poly (lactic acid),” Journal of Polymers and the Environment, vol. 9, no. 2, pp 63–84, 2001.
[3] L. T. Lim, R. Auras, and M. Rubino, “Processing technologies for poly (lactic acid),” Progress in polymer science, vol. 33, no.8, pp. 820–852, 2008.
[4] K. S. Anderson, S. H. Lim, M. A. Hillmyer,“Toughening of polylactide by melt blending with linear low-density polyethylene,”Journal of Applied Polymer, vol. 89, no.14, pp. 3757–3768, 2003.
[5] B. Boubekeur, N. Belhaneche-Bensemra, and V. Massardier,“Valorization of waste jute fibers in developing low-density polyethylene/poly lactic acid bio-based composites,” Journal of Reinforced Plastics and Composites, vol. 34, no. 8, pp. 649–661, 2015.
[6] A. M. Garjria, V. Dave, R. A. Gross, and S. P. McCarthy,“Miscibility and biodegradability of blends of poly(lactic acid) and poly(vinyl acetate),” Polymer, vol. 37, no. 3, pp. 437–444, 1996.
[7] M. Sheth, R. A. Kumar, V. Dave, R. A. Gross, and S. P. McCarthy,“Biodegradable polymer blends of poly (lactic acid) and poly (ethylene glycol),”Journal of Applied Polymer Science, vol. 66, no.8, pp. 1495–1505, 1997.
[8] Y. Cha, and C. G. Pitt, “The biodegradability of polyester blends,” Biomaterials, vol. 11, no. 2, pp. 108–112, 1990.
[9] L. L. Zhang, C. D. Xiong, and X. M. Deng,“Miscibility, crystallization and morphology of poly (β-hydroxybutyrate)/poly (d, l-lactide) blends,” Polymer, vol. 37, no. 2, pp. 235–241, 1996.
[10] M. R. Lostocco, and S. J. Huang,“Aliphatic polyester blends based upon poly (lactic acid) and oligomeric poly (hexamethylene succinate),” Journal of Macromolecular Science, Part A Pure and Applied Chemistry, vol. 34, no. 11, pp. 2165–2175, 1997.
[11] N. Ljungberg, and B. Wesslen, “The effects of plasticizers on the dynamic mechanical and thermal properties of poly(lactic acid),” Journal of Applied Polymer Science, vol. 86, no. 5, pp.1227–1234, 2002.
[12] M. Maiza, M. T. Benaniba, and V. Massardier,“Plasticizing effects of citrate esters on properties of poly (lactic acid),” Journal of Polymer Engineering, vol. 36, no. 4, pp. 371–380, 2016.
[13] J. Milton Harris,“Poly(ethylene glycol) chemistry: biotechnical and biomedical applications”, Springer science Business Media, New York, 1992.
[14] S. Jacobsen, and H. G. Fritz,“Plasticizing polylactide - the effect of different plasticizers on the mechanical properties”, Polymer Engineering & Science, vol. 39, no.7, pp. 1303–1310, 1999.
[15] N. Stoehr, B; Baudrit, E. Haberstroh, M. Nase, P. Heidemeyer, and M. Bastian, “Properties and weldability of plasticized polylactic acid films,” Journal of Applied Polymer Science, vol. 131, no. 12, pp. 40394–40403, 2014.
[16] F. J. Li, J. Z. Liang, S. D. Zhang, and B. Zhu, “Tensile Properties of Polylactide/Poly(ethylene glycol) Blends,” Journal of Polymers and the Environment, vol. 23, no, 3, pp. 407–415, 2015.
[17] R. Song, R. Xue, H. He, Y. Liu, and Q. L. Xiao, “The structure and properties of chitosan/polyethylene glycol/silica ternary hybrid organic-inorganic films,”Chinese Journal of Polymer Science, vol. 26, no. 5, pp.621–630, 2008.
[18] I. Pillin, N. Montrelay, and Y. Grohens, “Thermo-mechanical characterization of plasticized PLA: Is the miscibility the only significant factor?”Polymer, vol.47, no.13, pp.4676–4682, 2006.
[19] Y. Hu, M. Rogunova, V. Topolkaraev, A. Hiltner, and E. Baer, “Aging of poly (lactide)/poly (ethylene glycol) blends. Part 1. Poly (lactide) with low stereoregularity,” Polymer, vol. 44, no. 19, pp. 5701–5710, 2003.
[20] F. Yu, K. Prashantha, J. Soulestin, M. F. Lacrampe, and P. Krawczak, “Plasticizedstarch/poly (ethylene oxide) blends prepared by extrusion,” Carbohydrate Polymers, vol. 91. No. 1, pp. 253–261, 2013.
[21] M. Baiardo, G. Frisoni, M. Scandola, M. Rimelen, D. Lips, K. Ruffieux, and E. J. Wintermantel, “Thermal and mechanical properties of plasticized poly (L-lactic acid),” Journal of Applied Polymer Science, vol. 90, no. 7, pp. 1731–1738, 2003.
[22] A. Nijenhuis, E. Colstee, D. W. Grijpma, and A. J. Pennings, “High molecular weight poly (L-lactide) and poly (ethylene oxide) blends: Thermal characterization and physical properties,” Polymer, vol.37, no. 26, pp. 5849–5857, 1996.