Preparation and Properties of Biopolymer from L-Lactide (LL) and ε-Caprolactone (CL)

Biopolymers have gained much attention as ecofriendly alternatives to petrochemical-based plastics because they are biodegradable and can be produced from renewable feedstocks. One class of biopolyester with many potential environmentally
friendly applications is polylactic acid (PLA) and polycaprolactone (PCL). The PLA/PCL biodegradable copolyesters were synthesized by bulk ring-opening copolymerization of successively added Llactide (LL) and ε-caprolactone (CL) in the presence of toluene, using 1-hexanol as initiator and stannous octoate (Sn(Oct)2) as catalyst. Reaction temperature, reaction time and amount of catalyst were evaluated to obtain optimum reaction conditions. The results showed that the %conversion increased with increases in reaction temperature and reaction time, but after a critical amount of catalyst was reached the %conversion decreased. The yield of PLA/PCL biopolymer achieved 98.02% at the reaction temperature 160 °C, amount of catalyst 0.3 mol% and reaction time of 48 h. In addition, the thermal properties of the product were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

• A. Buasri
• N. Chaiyut
• K. Iamma
• K. Kongcharoen
• K. Cheunsakulpong

• Biopolymer
• Polylactic Acid (PLA)
• Polycaprolactone (PCL)
• L-Lactide (LL)
• ε-Caprolactone (CL)

[1] L. Averous, "Biodegradable multiphase systems based on plasticized starch,” J. Macromol. Sci. Polym. Rev., C44, pp. 231–274, 2004.
[2] R. Ouhib, B. Renault, H. Mouaziz, C. Nouvel, E. Dellacherie, J.L. Six, "Biodegradable amylose-g-PLA glycopolymers from renewable resources,” Carbohyd. Polym., 77, pp. 32–40, 2009.
[3] K.M. Nampoothiri, N.R. Nair, R.P. John, "An overview of the recent developments in polylactide (PLA) research,” Bioresour. Technol., 101, pp. 8493–8501, 2010.
[4] V. Langlois, K. Vallee-Rehel, J.J. Peron, A. Borgne, M. Walls, Philippe Guerin, "Synthesis and hydrolytic degradation of graft copolymers containing poly(lactic acid) side chains: in vitro release studies of bioactive molecules,” Polym. Degrad. Stab., 76, pp. 411–417, 2002.
[5] M. Vert, M.S. Li, G. Spenlehauer, P. Guerin, "Bioresorbability and biocompatibility of aliphatic polyesters,” J. Mater. Sci. Mater. Med., 3, pp. 432–446, 1992.
[6] R.E. Drumright, P.R. Gruber, D.E. Henton, "Polylactic Acid Technology,” Adv. Mater., 12, pp. 1841–1846, 2000.
[7] S. Karjomaa, T. Suortti, R. Lempiainen, J.F. Selin, M. Itävaara, "Microbial degradation of poly-(l-lactic acid) oligomers,” Polym. Degrad. Stab., 59, pp. 333–336, 1998.
[8] V. Darcos, H.A. Tabchi, J. Coudane, "Synthesis of PCL–graft–PS by combination of ROP, ATRP, and click chemistry,” Eur. Polymer J., 47, pp. 187–195, 2011.
[9] A.C. Albertsson, I.K. Varma, "Recent developments in ring opening polymerization of lactones for biomedical applications,” Biomacromolecules, 4, pp. 1466–1486, 2003.
[10] P. Lecomte, R. Riva, S. Schmeits, J. Rieger, B.K. Van, C. Jérôme, R. Jérôme, "New prospects for the grafting of functional groups onto aliphatic polyesters. Ring-opening polymerization of alpha- or gamma- substituted epsilon-caprolactone followed by chemical derivatization of the
substituents,” Macromol. Symp., 240, pp. 157–165, 2006.
[11] M.H. Huang, S. Li, M. Vert, "Synthesis and degradation of PLA–PCL–PLA triblock copolymer prepared by successive polymerization of ε- caprolactone and DL-lactide,” Polymer, 45, pp. 8675–8681, 2004.
[12] D.W. Hutmacher, "Scaffold design and fabrication technologies for engineering tissues-state of the art and future perspectives,” J. Biomater. Sci. Polym. Ed., 12, pp. 107–124, 2001.
[13] S. Li, H. Garreau, M. Vert, "Structure-property relationships in the case of the degradation of massive aliphatic poly(