PEMA-ko-PHEMA Üzerine Aşılanan Poly(ɛ-kaprolakton)’ un Termal Bozunma Kinetiğinin İncelenmesi

Serbest radikal polimerizasyonuyla sentezlenen %5 oranında 2-hidroksietilmetakrilat (HEMA) içeren poli(etilmetakrilat)-ko-poli(2-hidroksi etilmetakrilat), PEMA-ko-PHEMA, kopolimerinin -OH ucuna, ?-kaprolakton halka açılması polimerizasyonu metoduyla aşılandı. Sentezlenen polimerler FTIR ve 1H-NMR teknikleriyle karakterize edildi. PEMA-ko-PHEMA-a-PCL aşı kopolimerinin termal degradasyon kinetiği farklı ısıtma hızlarında termogravimetrik analizle araştırıldı. Aktivasyon enerjisi Kissinger, Flynn-Wall-Ozawa ve Tang metotlarıyla, reaksiyon mekanizması bilinmeden, sırasıyla 108.58, 113.88 ve 108.35 kJ/mol olarak hesaplandı. Farklı integral ve diferansiyel metotlar kullanılarak bu değerler karşılaştırıldı. Deneysel sonuçların analiziyle, çalışılan dönüşüm aralığında reaksiyon mekanizması R3 olarak belirlendi.

Investigation of Thermal Degradation Kinetics of Poly(Ɛ-caprolactone) Grafted onto PEMA-co-PHEMA

Poly(ethyl methacrylate)-co-poly(2-hydroxyethyl methacrylate), PEMA-co-PHEMA, which containing 5% 2-hydroxyethyl methacrylate (HEMA) was synthesized by the free radical polymerization. ɛ-caprolactone was grafted -OH side group of PEMA-co-PHEMA via ring opening polymerization method. A newly synthesized PEMA-co-PHEMA-g-PCL which grafted onto PEMA-co-PHEMA were characterized by experimental measurements such as FTIR, 1H NMR and TGA techniques. The reaction mechanism of degradation process and the kinetic parameters of the polycaprolactone grafted onto PEMA-co-PHEMA in nitrogen environment were investigated by thermogravimetric analysis (TGA) at different heating rates. The evident activation energies of thermal degradation for polycaprolactone, as defined by the Kissinger’s, Flynn–Wall–Ozawa and Tang methods, which does not necessary knowledge of the reaction mechanism (RM), were 108.58, 113.88 and 108.35 kJ/mol, respectively. These values were compared using different integral and differential methods. An analysis of the experimental results proposed that the reaction mechanism was an R3 deceleration type in the conversion range (240%) studied

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[1] Mao, Y. and Gleason, K. K. , 2004 , Hot Filament Chemical Vapor Deposition of Poly(glycidylmethacrylate) Thin Films Using tertButyl Peroxide as an Initiator, Langmuir, 20, 2484- 2488.
[2] Kostina, N.Y., Sharifi ,S., Pereira, A.S., Michalek, J., Grijpma, D.W., Emmenegger C.R. , 2013, Novel antifouling self-healing poly(carboxybetaine methacrylamide-co-HEMA) nanocomposite hydrogels with superior mechanical properties. J. Mater. Chem. B 1 5644–5650.
[3] Park, J.T., Koh, J.H., Seo, J.O., Kim, J.H. , 2011, Formation of mesoporous TiO2 with large surface areas, interconnectivity and hierarchical pores for dye-sensitized solar cells.J. Mater. Chem. 2 ,17872– 17880.
[4] Kostina, N.Y, Emmenegger, C.R., Houska, M., Brynda, E., Michalek ,J. , 2012, Non-fouling Hydrogels of 2-Hydroxyethyl Methacrylate and Zwitterionic Carboxybetaine (Meth)acrylamides, Biomacromolecules 13, 4164–4170.
[5] Peppas, N.A. , Bures, P. , Leobandung, W. , Ichikawa, H. , 2000, Hydrogels in Pharmaceutical Formulations, Eur. J. Pharma. Biopharm. 50 , 27– 46.
[6] Peppas, N.A. , Hilt, J.Z. , Khademhosseini,A., Langer, R. , 2006, Hydrogels in Biology and Medicine: From Fundamentals to Bionanotechnology ,Adv. Mater. 18 ,1345–1360.
[7] Hoffman, A.S. , 2002 , Hydrogels for biomedical applications., Adv. Drug Deliv. Rev. 54 , 3–12.
[8] Brahim S, Narinesingh D, Elie AG. , 2003,Synthesis and hydration properties of pHsensitive p(HEMA)-based hydrogels containing 3- (trimethoxysilyl)propyl methacrylate. Biomacromolecules;4: 497–503.
[9] Kou JH, Fleisher D, Amidon GL. , 1990, Modeling drug release from dynamically swelling poly(hydroxyethyl methacrylate-co-methacrylic acid) hydrogels. J Control Release;12:241–50.
[10] Albin G, Horbett TA, Miller SR, Ricker NL. , 1987, Theoretical and experimental studies of glucose sensitive membranes. J Control Release ;6:267–91.
[11] Nakayama A, Kawasaki N, Maeda Y, Arvanitoyannis I, Ariba S, Yamamoto N. , 1997,Study of biodegradability of poly(evalerolactone-co-L-lactide)s. J Appl Polym Sci;66:741–8.
[12] Pitt, C.G. , 1990, Poly(epsilon -caprolactone) and its copolymers. In: Chassin M, Langer R, editors. Biodegradable polymers as drug delivery systems. New York: Dekker;. p. 71-119.
[13] Albertsson, A.C., Varma, I.K. , 2003, Recent developments in ring opening polymerization of lactones for biomedical applications,Biomacromolecules;4(6):1466-86.
[14] Woodruff, M. A., Hutmacher, D. W. , 2010, The return of a forgotten polymer: Polycaprolactone in the 21st century. Progress in Polymer Science, 35, 1217–1256.
[15] Hatakeyama, T.; Quinn, F. X. , 1994 Thermal Analysis: Fundamentals and Applications to Polymer Science; Wiley: Chichester, England.
[16] Criado, J.M.;Ma´lek, J.; Ortega, A. , 1989 Thermochim Acta, 147, 377.
[17] Ma, S.; Hill, J. O.; Heng, S. , 1991, J Therm Anal, 37, 1161.
[18] Kissinger, 1957, H. E. Anal Chem, 29, 1702.
[19] Doyle, C. D. , 1965, Nature, 207, 240.
[20] Flynn, J. H.; Wall, L. A. , 1966, J Res Natl Bur Stand Sect A, 70, 487.
[21] Ozawa, T. , 1965, Bull Chem Soc Jpn, 38, 1881.
[22] Tang, W.; Liu, Y.; Zhang, C. H.; Wang, C. , 2003, Thermochim Acta, 40, 839.
[23] Coats, A. W.; Redfern, J. P. , 1965, Nature, 207, 290.
[24] Van Krevelen, D. W.; Van Heerden, C.; Huntjons, F. J. Fuel, , 1951, 30, 253.
[25] Horowitz, H. H.; Metzger, G. , 1963,Anal Chem , 35, 1464.
[26]Kurt, A., 2009, Thermal Decomposition Kinetics of Poly(nButMA-b-St)Diblock Copolymer Synthesized by ATRP, Journal of Applied Polymer Science, 114, 624–629