Thermal-oxidative Degradation of PGA, PLLA, and Random Binary PLLA-PGA Copolymers

Document Type : Research Paper

Authors

1 Facuty of Caspian, College of Engineering, University of Tehran, Rezvanshahr, Gilan, Iran

2 Process Development & Control Group, Process Development & Equipment Technology Division, Research Institute of Petroleum Industry, Tehran, I. R. Iran

3 School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran

Abstract

Dimerization process is essential for producing copolymers. The features of dimerization process like thermal-oxidative degradation should be well known to reach maximum efficiency and a superior reactor design. Also, the degradation mechanism of biodegradable polymers is important during sterilization processes. Thermal-oxidative degradation of PGA, PLLA, and their binary copolymers was investigated under isothermal heating as well as dynamic heating. All the samples were prepared by a polycondensation process and were characterized by TG, DTG, DSC, and HNMR analyses. Activation energy under dynamic heating was obtained by using Friedman plot. A new three stage mechanism, namely random, transition, and specific stages is proposed for dynamic heating degradation. Isothermal heating investigation is conducted under an inert atmosphere, and frequency factor and activation energy were achieved. It was found that the activation energy under isothermal heating is generally higher than that under dynamic heating. It was found that the rate of degradation increases significantly with an increase in temperature. The effects of pressure on the degradation rate were studied in different atmospheres with various oxygen partial pressures. Pressure effect was correlated by a second order polynomial in terms of total pressure. The obtained activation energies under isothermal heating were in good agreement with those reported by others. The complete kinetic scheme suitable for reactor design for the thermal-oxidative degradation of the samples was reported. Finally, the optimal operational conditions for the dimerization process were reported.

Keywords


      [1]     Dickers K. J., Huatan H., and Cameron R. E., “Polyglycolide-Based Blends for Drug Delivery: A Differential Scanning Calorimetry Study of the Melting Behavior,” Journal of Applied Polymer Science, 2003, 89, 2937-2939.
      [2]     Doppalapudi S., Jain A., Khan W., and Domb A. J., “Biodegradable Polymers-an Overview,” Polymer Advanced Technology Journal, 2014, 25, 427-435.
      [3]     Wang Z., Zhao Y., Wang F., and Wang J., “Syntheses of Poly (Lactic Acid-Co-Glycolic Acid) Serial Biodegradable Polymer Materials via Direct Melt Polycondensation and their Characterization,” Journal of Applied Polymer Science, 2006, 99, 244-252.
      [4]     Gupta A. and Kumar V., “New Emerging Trends in Synthetic Biodegradable Polymers- Polylactide: A Critique,” European Polymer Journal, 2007, 43, 4053-4074.
            [5]            Motta A. C. and Duek E. A. R, “Synthesis and Characterization of a Novel Terpolymer Based on L-Lactide, D, L-Lactide and Trimethylene Carbonate,” Materials Research Journal, 2014, 17, 619-626.
            [6]            Farnia S. M., Mohammadi-Rovshandeh J., and Sarbolouki M. N., “Synthesis and Characterization of Novel ABA Triblock Copolymers from L-Lactide, Glycolide and PPG,” Journal of Applied Polymer Science,1999, 73, 633-637.
      [7]     Mohammadi-Rovshandeh J., Farnia S. M., and Sarbolouki M. N., “Synthesis and Characterization of Novel ABA Triblock Copolymers from L-Lactide, Glycolide and PEG,” Journal of Applied Polymer Science,1999, 74, 2004-2009.
            [8]            Ajioka M., Enomoto K., Suzuke K., and Yamaguchi A., “Basic Properties of Polylactic Acid Produced by The Direct Condensation Polymerization of Lactic Acid,” Bulletin of the Chemical Society of Japan, 1995, 68, 2125-2131.
      [9]     Ajioka M., Suizo H., Higuci C., and Kashima T., “Aliphatic Polyester and their Copolymers Synthesized Through Direct Condensation Polymerization of Lactic Acid,” Polymer Degradation and Stability, 1998, 59, 137-143.
    [10]    Takasu A., Narukawa Y., and Hirabayashi T., “Direct Dehydration Polycondensation of Lactic Acid Catalyzed by Water-Stable Lewis Acids,” Journal of Polymer Science, 2006, 44, 5247-5253.
         [11]         Mohammadikhah R., Asadi-Malekshah R., and M. Rovshandeh J., “Preparation, Characterization and Thermal-Oxidative Degradation of Poly-L Lactic Acid (PLLA). 14thNational Chemical Engineering Congress,” Sharif University of Technology, 2012, Tehran, Iran, 11215, 1-8.
         [12]         Nagarajan S., Tsibouklis J., and Reddy R. S., “Direct Condensation of D, L- And L-Lactic Acids: Effect of Alcl3 Catalyst on Microstructural Arrangements of Homopolymers and Copolymers,” Iran Polymer Journal, 2011, 20, 523-533.
    [13]    Carothers W., Dorough G., and Van Natta F., “Studies of Polymerization and Ring Formation,” Journal of the American Chemical Society, 1932, 54, 761-772.
         [14]         Kim S. H. and Kim Y. H., “Direct Condensation Polymerization of Lactic Acid,” Macromolecular Symposia, 1999, 144, 277-287.
    [15]    Verderio P., Bonetti P., Colombo M., Pandolfi L., and Prosperi D., “Intracellular Drug Release from Curcumin-Loaded PLGA Nanoparticles Induces G2/M Block in Breast Cancer Cells,” Biomacromolecules Journal, 2013, 14, 672–682.
         [16]         Athanasiou K. A., Niederauer G. G., and Agrawal C. M., “Sterilization, Toxicity, Biocompatibility and Clinical Applications of Polylactic Acid/Polyglycolic Acid Copolymers,” Biomaterials, 1996, 17, 93-102.
         [17]         Jamshidi K., Hyon S., and Ikada Y., “Thermal Characterization of Polylactides,” Polymer, 1988, 29, 2229-2234.
         [18]         Zhang X., Wyss U., Pichora D., Goosen M., “An Investigation of the Synthesis and Thermal Stability of Poly (DL-Lactide),” Polymer Bulletin, 1992, 27, 623-629.
         [19]         Nalbandi A., “Kinetics of Thermal Degradation of Polylactic Acid under N2 Atmosphere,” Iranian Polymer Journal, 2001, 6, 371-376.
    [20]    Gupta M. C. and Deshmukh V. G., “Thermal Oxidative Degradation of Poly (Lactic Acid),” Colloid & Polymer Science, 1982, 260, 308-311.
    [21]    Gupta M. C. and Deshmukh V. G., “Thermal Oxidative Degradation of Poly (Lactic Acid),” Colloid & Polymer Science, 1982, 260, 514-517.
    [22]    Wachsen O., Reichert K., Kruger R., Much H., et al., “Thermal Decomposition of Biodegradable Polyesters-III. Studies on the Mechanisms of Thermal Degradation of Oligo-L-Lactide Using SEC, LACCC and MALDI-TOF-MS,” Polymer Degradation and Stability, 1997, 55, 225-231.
    [23]    Wachsen O., Platkowski K., and Reichert K., “Thermal Degradation of Poly-L-Lactide- Studies on Kinetics, Modeling and Melt Stabilization,” Polymer Degradation and Stability, 1997, 57, 87-94.
    [24]    Omura M., Tsukegi T., Shirai Y., Nishida H., et al., “Thermal Degradation of Poly (Lactic Acid) in A Blend with Polyethylene,” Industrial & Engineering Chemistry Research, 2006, 45, 2949-2953.
    [25]    Sivalingam G. and Madras G., “Thermal Degradation of Binary Physical Mixtures and Copolymers of Poly (Ε-Caprolactone), Poly (D, L-Lactide), Poly (Glycolide),”Polymer Degradation and Stability, 2004, 84, 393-398.
    [26]    Mohammadikhah R. and Mohammadi-Rovshandeh J., “Thermal Degradation and Kinetic Analysis of Pure Polyglycolic Acid in Presence of Humid Air,” Iranian Polymer Journal, 2008, 17, 691-701.
    [27]    Drumright R., Gruber P., and Henton D., “Polylactic Acid Technology,” Advanced Materials, 2000, 12, 1841-1846.
    [28]    Kopinke F. D. and Mackenzie K., “Mechanistic Aspects of the Thermal Degradation of Poly (Lactic Acid) and Poly (Β-Hydroxybutyric Acid),” Journal of Analytical and Applied Pyrolysis, 1997, 40-41, 43-53.
         [29]         Shih Y. and Chieh Y., “Thermal Degradation Behavior and Kinetic Analysis of Biodegradable Polymers Using Various Comparative Models,” Macromolecular Theory and Simulations, 2007, 16, 101-110.
         [30]         Chujo K., Kobayashi H., Suzuki J., and Tokuhara S., “Physical and Chemical Characteristics of Polyglycolide,” Macromolecular Chemistry and Physics Journal, 1967, 100, 267-270.
    [31]    Mohammadi-Rovshandeh J., Farnia S., and Sarbolouki M., “Synthesis and In-Vitro Degradation of D, L-Lactide-Glycolide Copolymers,” 6th ISOC. Tabriz, Iran, 1997.
         [32]         M. Rovshandeh J., Farnia S. M. F., and Sarbolouki M. N., “In-Vitro Degradation of Lactide-Glycolide Copolymers: PLA35GA30,” Journal of Applied Polymer Science, 1998, 69, 627-630.
         [33]         Mohammadi-Rovshandeh J. and Sarbolouki M., “Synthesis and In-Vitro Hydrolytic Degradation of Polyglycolic Acid and Its L-Lactide Copolymer,” Iranian Polymer Journal, 2001, 10, 53-58.
    [34]    Proikakis C. S., Mamouzelos N. J., Tarantili P. A., and Andreopoulos A. G., “Swelling and Hydrolytic Degradation of Poly (D, L-Lactic Acid) In Aqueous Solutions,” Polymer Degradation and Stability, 2006, 91, 614-619.
         [35]         King E. and Cameron R., “Effect of Hydrolytic Degradation on the Microstructure of Poly (Glycolic Acid),” Applied Polymer Science, 1997, 66, 1681-1690.
    [36]    Mobedi H., Mashak A., Nekoomanesh M., and Orafai H., “L-Lactide Additive and In Vitro Degradation Performance of Poly (L-Lactide) Films,” Iranian Polymer Journal, 2011, 21, 237-245.
    [37]    Dorgan J. R., Lehermeier H., and Mang M., “Thermal and Rheological Properties of Commercial Grade Poly (lactic acids),” Journal of Polymers and the Environment, 2000, 8, 1-9.
    [38]    Denq B., Chiu W., and Lin K., “Kinetic Model of Thermal Degradation of Polymers for Nonisothermal Process,” Journal of Applied Polymer Science, 1997, 66, 1855-1868.
         [39]         Minying L., Lijun G., Qingxiang Z., Yudong W., et al., “Thermal Degradation Process and Kinetics of Poly (Dodecamethyleneisophthalamide),” Chemical Journal on Internet, 2003, 5, 43-53.
    [40]    Friedman H., “Kinetics of Thermal Degradation of Char-Forming Plastics from Thermogravimetry. Application to A Phenolic Plastic,” Journal of Polymer Science, 1964, 6, 183-195.
    [41]    Li X., Huang M., Guan G., and Sun T., “Kinetics of Thermal Degradation of Thermotropic Poly (P-Oxybenzoate-Coethylene Terephthalate) by Single Heating Rate Methods,” Polymer International, 1998, 46, 289-297.
    [42]    Li X. and Huang M., “Thermal Decomposition Kinetics of Thermotropic Poly (Oxybenzoate-Co-Oxynaphthoate) Vectra Copolyester,” Polymer Degradation and Stability, 1999, 64, 81-90.
    [43]    Kelen T., “Polymer Degradation,” Van Nostrand Company, New York, 1983.
         [44]         McNeill I. and Leiper H., “Degradation Studies of Some Polyesters and Polycarbonates: 3-Polyglycolide,” Polymer Degradation and Stability, 1985, 12, 373-385.
    [45]    Smith JM., Van Ness CH., and Abbott M. M., “Introduction to Chemical Engineering Thermodynamics,” McGraw-Hill, New York, 2001.
    [46]    Prausnitz J. M., Lichtenthaler N. R., and Azevedo G. E., “Molecular Thermodynamics of Fluid Phase Equilibria,” New Jersey, Prentice-Hall Inc., 1999.
    [47]    Balakrishnan R. and Guria C., “Thermal Degradation of Polystyrene In The Presence of Hydrogen by Catalyst in Solution,” Polymer Degradation and Stability, 2007, 92, 1583-1591.