A set of materials has been prepared by sol–gel process containing different quantities of hydroxyapatite (0, 2.5 and 5% HAp w/w) using as silica precursors glycidyloxypropyltrimethoxysilane (GPTMS) and triethoxyvinylsilane (VTES). In order to optimize the curing process to obtain sintherized systems (inorganic network) or hybrid systems (organic–inorganic) a TG and FTIR studies have been developed and degradation kinetic triplet parameters were obtained (the activation energy, pre-exponential factor, and function of degree of conversion). The kinetic study was analyzed by means of an integral isoconversional non-isothermal procedure (model free), and the kinetic model was determined by the Coats–Redfern method and through the compensation effect (IKR). All the systems followed the n = 6 kinetic model. The addition of HAp increases the thermal stability of the systems. The isothermal degradation was simulated from non-isothermal data, and the curing process could be defined to obtain the two types of materials. Temperature under 250 °C allows the formation of hybrids networks.
1. Wen, JY, Wilkes, GL. Organic/inorganic hybrid network materials by the sol–gel approach. Chem Mater. 1996;8:1667–1681. .
2. Brinker CJ , Scherer GW. Sol–gel science: the physics and chemistry of sol–gel processing, London: Academic Press; 1990.
3. Guglielmi, M. Sol–gel coatings on metals. J Sol–Gel Sci Technol. 1997;8:443–449.
4. Wright, JD, Sommerdijk, N. Sol–gel materials chemistry and applications. London: CRC Press; 2001.
5. Vasconcelos, DCL, Carvalho, JAN, Mantel, M, Vasconcelos, WL. Corrosion resistance of stainless steel coated with sol–gel silica. J Non-Cryst Solids. 2000;273:135–139. .
6. Conde, A, De Damborenea, J, Duran, A, Menning, M. Protective properties of a sol–gel coating on zinc coated steel. J Sol–Gel Sci Technol. 2006;37:79–85. .
7. Sayilkan, H, Sener, S, Sener, E, Sulu, M. The sol–gel synthesis and application of some anticorrosive coating materials. Mater Sci. 2003;39:733–739. .
8. Parkhill, RL, Knobbe, ET, Donley, MS. Application and evaluation of environmentally compliant spray-coated ormosil films as corrosion resistant treatments for aluminum 2024-T3. Prog Org Coat. 2001;41:261–265. .
9. Chan, Z, Ai’mei, L, Xiao, Z, Miao, F, Juan, H, Hongbing, Z. Microstructures and properties of ORMOSIL comprising methyl, vinyl, and [gamma]-glycidoxypropyl-substitued silica. Opt Mater. 2007;29:1543–1547. .
10. Li, PJ, Ohtsuki, C, Kokubo, T, Nakanishi, K, Soga, N, Nakamura, T, Yamamuro, T. Apatite formation induced by silica-gel in a simulated body-fluid. J Am Ceram Soc. 1992;75:2094–2097. .
11. Kawashita, M, Nakao, M, Minoda, M, Kim, HM, Beppu, T, Miyamoto, T, Kokubo, T, Nakamura, T. Apatite-forming ability of carboxyl group-containing polymer gels in a simulated body fluid. Biomaterials. 2003;24:2477–2484. .
12. Chico, B, Galván, JC, de la Fuente, D, Morcillo, M. Electrochemical impedance spectroscopy study of the effect of curing time on the early barrier properties of silane systems applied on steel substrates. Prog Org Coat. 2007;60:45–53. .
13. Garcia-Heras, M, Jimenez-Morales, A, Casal, B, Galvan, JC, Radzki, S, Villegas, MA. Preparation and electrochemical study of cerium-silica sol–gel thin films. J Alloys Compd. 2004;380:219–224. .
14. Galliano, P, De Damborenea, JJ, Pascual, MJ, Duran, A. Sol–gel coatings on 316L steel for clinical applications. J Sol–Gel Sci Technol. 1998;13:723–727. .
15. Ohtsuki, C, Miyazaki, T, Tanihara, M. Development of bioactive organic–inorganic hybrid for bone substitutes. Mater Sci Eng C. 2002;22:27–34. .
16. García, C, Ceré, S, Durán, A. Bioactive coatings prepared by sol–gel on stainless steel 316L. J Non-Cryst Solids. 2004;348:218–224. .
17. García, C, Ceré, S, Durán, A. Bioactive coatings deposited on titanium alloys. J Non-Cryst Solids. 2006;352:3488–3495. .
18. Ballarre, J, Lopez, DA, Rosero, NC, Duran, A, Aparicio, M, Cere, SM. Electrochemical evaluation of multilayer silica-metacrylate hybrid sol–gel coatings containing bioactive particles on surgical grade stainless steel. Surf Coat Technol. 2008;203:80–86. .
19. Salla, JM, Cadenato, A, Ramis, X, Morancho, JM. Thermoset cure kinetics by isoconversional methods. J Therm Anal Calorim. 1999;56:771–781. .
20. Vyazovkin, S, Wight, CA. Kinetics in solids. Annu Rev Phys Chem. 1997;48:125–149. .
21. Coats, AW, Redfern, JP. Kinetic parameters from thermogravimetric data. Nature. 1964;201:68 .
22. Ramis, X, Salla, JM, Cadenato, A, Morancho, JM. Simulation of isothermal cure of a powder coating—non-isothermal DSC experiments. J Therm Anal Calorim. 2003;72:707–718. .
23. Ramis, X, Cadenato, A, Salla, JM, Morancho, JM, Valles, A, Contat, L, Ribes, A. Thermal degradation of polypropylene/starch-based materials with enhanced biodegradability. Polym Degrad Stab. 2004;86:483–491. .
24. Vyazovkin, S, Linert, W. The application of isoconversional methods for analyzing isokinetic relationships occurring at thermal-decomposition of solids. J Solid State Chem. 1995;114:392–398. .
25. Vyazovkin, S, Linert, W. False isokinetic relationships found in the nonisothermal decomposition of solids. Chem Phys. 1995;193:109–118. .
26. Chrissafis, K. Kinetics of thermal degradation of polymers. J Therm Anal Calorim. 2009;95:273–283. .
27. Garcia, SJ, Serra, A, Ramis, X, Suay, J. Influence of the addition of erbium and ytterbium triflates in the curing kinetics of a DGEBA/o-tolybiguanide powder mixture. J Therm Anal Calorim. 2007;89:223–231. .
28. Garcia, SJ, Ramis, X, Serra, A, Suay, J. Cationic crosslinking of solid DGEBA resins with ytterbium(III) trifluoromethanesulfonate as initiator. J Therm Anal Calorim. 2006;83:429–438. .
29. Salla, JM, Morancho, JM, Cadenato, A, Ramis, X. Non-isothermal degradation of a thermoset powder coating in inert and oxidant atmospheres. J Therm Anal Calorim. 2003;72:719–728. .