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Achilias DS, Verros GD. Modeling of diffusion-controlled reactions in free radical solution and bulk polymerization: Model validation by DSC experiments. J Appl Polym Sci 2010. [DOI: 10.1002/app.31675] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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52
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Achilias DS, Bikiaris DN, Papastergiadis E, Giliopoulos D, Papageorgiou GZ. Characterization and Crystallization Kinetics of in situ Prepared Poly(propylene terephthalate)/SiO2
Nanocomposites. MACROMOL CHEM PHYS 2009. [DOI: 10.1002/macp.200900327] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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53
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Verros GD, Achilias DS. Modeling gel effect in branched polymer systems: Free-radical solution homopolymerization of vinyl acetate. J Appl Polym Sci 2009. [DOI: 10.1002/app.29252] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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54
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Papageorgiou GZ, Achilias DS, Bikiaris DN. Crystallization Kinetics and Melting Behaviour of the Novel Biodegradable Polyesters Poly(propylene azelate) and Poly(propylene sebacate). MACROMOL CHEM PHYS 2008. [DOI: 10.1002/macp.200800441] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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55
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Sideridou ID, Achilias DS, Kostidou NC. Copolymerization kinetics of dental dimethacrylate resins initiated by a benzoyl peroxide/amine redox system. J Appl Polym Sci 2008. [DOI: 10.1002/app.28093] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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56
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Achilias DS, Roupakias C, Megalokonomos P, Lappas AA, Antonakou EV. Chemical recycling of plastic wastes made from polyethylene (LDPE and HDPE) and polypropylene (PP). JOURNAL OF HAZARDOUS MATERIALS 2007; 149:536-42. [PMID: 17681427 DOI: 10.1016/j.jhazmat.2007.06.076] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The recycling of either model polymers or waste products based on low-density polyethylene (LDPE), high-density polyethylene (HDPE) or polypropylene (PP) is examined using the dissolution/reprecipitation method, as well as pyrolysis. In the first technique, different solvents/non-solvents were examined at different weight percent amounts and temperatures using as raw material both model polymers and commercial products (packaging film, bags, pipes, food-retail outlets). The recovery of polymer in every case was greater than 90%. FT-IR spectra and tensile mechanical properties of the samples before and after recycling were measured. Furthermore, catalytic pyrolysis was carried out in a laboratory fixed bed reactor with an FCC catalyst using again model polymers and waste products as raw materials. Analysis of the derived gases and oils showed that pyrolysis gave a mainly aliphatic composition consisting of a series of hydrocarbons (alkanes and alkenes), with a great potential to be recycled back into the petrochemical industry as a feedstock for the production of new plastics or refined fuels.
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Papageorgiou GZ, Achilias DS, Bikiaris DN. Macromol. Chem. Phys. 12/2007. MACROMOL CHEM PHYS 2007. [DOI: 10.1002/macp.200790024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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58
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Papageorgiou GZ, Achilias DS, Bikiaris DN. Crystallization Kinetics of Biodegradable Poly(butylene succinate) under Isothermal and Non-Isothermal Conditions. MACROMOL CHEM PHYS 2007. [DOI: 10.1002/macp.200700084] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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59
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Achilias DS. Chemical recycling of poly(methyl methacrylate) by pyrolysis. Potential use of the liquid fraction as a raw material for the reproduction of the polymer. Eur Polym J 2007. [DOI: 10.1016/j.eurpolymj.2007.02.044] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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60
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Bikiaris DN, Papageorgiou GZ, Achilias DS, Pavlidou E, Stergiou A. Miscibility and enzymatic degradation studies of poly(ε-caprolactone)/poly(propylene succinate) blends. Eur Polym J 2007. [DOI: 10.1016/j.eurpolymj.2007.03.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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61
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Achilias DS. A Review of Modeling of Diffusion Controlled Polymerization Reactions. MACROMOL THEOR SIMUL 2007. [DOI: 10.1002/mats.200700003] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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62
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Sideridou ID, Achilias DS, Karabela MM. Sorption kinetics of ethanol/water solution by dimethacrylate-based dental resins and resin composites. J Biomed Mater Res B Appl Biomater 2007; 81:207-18. [PMID: 16941599 DOI: 10.1002/jbm.b.30655] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the present investigation the sorption-desorption kinetics of 75 vol % ethanol/water solution by dimethacrylate-based dental resins and resin composites was studied in detail. The resins examined were made by light-curing of bisphenol A glycol dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), bisphenol A ethoxylated dimethacrylate (Bis-EMA), and mixtures of these monomers. The resin composites were prepared from two commercial light-cured restorative materials (Z100 MP and Filtek Z250), the resin matrix of which is based on copolymers of the above-mentioned monomers. Ethanol/water sorption/desorption was examined in both equilibrium and dynamic conditions in two adjacent sorption-desorption cycles. For all the materials studied, it was found that the amount of ethanol/water sorbed or desorbed was always larger than the corresponding one reported in literature in case of water immersion. It was also observed that the chemical structure of the monomers used for the preparation of the resins directly affects the amount of solvent sorbed or desorbed, as well as sorption kinetics, while desorption rate was nearly unaffected. In the case of composites studied, it seems that the sorption/desorption process is not influenced much by the presence of filler. Furthermore, diffusion coefficients calculated for the resins were larger than those of the composites and were always higher during desorption than during sorption. Finally, an interesting finding concerning the rate of ethanol/water sorption was that all resins and composites followed Fickian diffusion kinetics during almost the whole sorption curve; however, during desorption the experimental data were overestimated by the theoretical model. Instead, it was found that a dual diffusion-relaxation model was able to accurately predict experimental data during the whole desorption curve. Kinetic relaxation parameters, together with diffusion coefficients, are reported for all resins and composites.
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63
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Sideridou ID, Achilias DS, Karava O. Reactivity of Benzoyl Peroxide/Amine System as an Initiator for the Free Radical Polymerization of Dental and Orthopaedic Dimethacrylate Monomers: Effect of the Amine and Monomer Chemical Structure. Macromolecules 2006. [DOI: 10.1021/ma0521351] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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64
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Papageorgiou GZ, Achilias DS, Karayannidis GP, Bikiaris DN, Roupakias C, Litsardakis G. Step-scan TMDSC and high rate DSC study of the multiple melting behavior of poly(1,3-propylene terephthalate). Eur Polym J 2006. [DOI: 10.1016/j.eurpolymj.2005.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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65
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Achilias DS, Papageorgiou GZ, Karayannidis GP. Evaluation of the Isoconversional Approach to Estimating the Hoffman-Lauritzen Parameters from the Overall Rates of Non-Isothermal Crystallization of Polymers. MACROMOL CHEM PHYS 2005. [DOI: 10.1002/macp.200500175] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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66
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Sideridou ID, Achilias DS. Elution study of unreacted Bis-GMA, TEGDMA, UDMA, and Bis-EMA from light-cured dental resins and resin composites using HPLC. J Biomed Mater Res B Appl Biomater 2005; 74:617-26. [PMID: 15889433 DOI: 10.1002/jbm.b.30252] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the present work the elution of residual monomers from light-cured dental resins and resin composites into a 75% ethanol:water solution was studied using High-Performance Liquid Chromatography (HPLC). The resins studied were made by light-curing of bisphenol A glycol dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA), ethoxylated bisphenol A glycol dimethacrylate [Bis-EMA(4)] and mixtures of these monomers. The resin composites were made from two commercial light-cured restorative materials (Z100 MP and Filtek Z250), the resin matrix of which is based on copolymers of these monomers. The effect of the curing time on the amount of monomers eluted was investigated. The concentration of the extractable monomers was determined at several immersion periods from 3 h to 30 days. For all the materials studied, it was observed that the chemical structure of the monomers used for the preparation of the resins, which defines the chemical and physical structure of the corresponding resin, directly affects the amount of eluted monomers, as well as the time needed for the elution of this amount. In the case of composites, it seems that the elution process it is not influenced by the presence of filler.
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Sideridou I, Achilias DS, Kyrikou E. Thermal expansion characteristics of light-cured dental resins and resin composites. Biomaterials 2004; 25:3087-97. [PMID: 14967543 DOI: 10.1016/j.biomaterials.2003.09.078] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2003] [Accepted: 09/19/2003] [Indexed: 11/25/2022]
Abstract
The thermal expansion characteristics of dental resins prepared by light-curing of Bis-GMA, TEGDMA, UDMA, Bis-EMA(4) or PCDMA dimethacrylate monomers and of commercial light-cured resin composites (Z-100 MP, Filtek Z-250, Sculpt-It and Alert), the organic matrix resin of which is based on different combinations of the above monomers, were studied by thermomechanical analysis (TMA). This study showed the existence of a glass transition temperature at around 35-47 degrees C for the resins and 40-45 degrees C for the composites; then the coefficient of linear thermal expansion (CLTE) was calculated at the temperature intervals 0-60 degrees C, 0-T(g) and T(g)-60 degrees C. The CLTE values of Bis-GMA, TEGDMA and UDMA resins are similar and lower than those of Bis-EMA (4) and PCDMA resins. The CLTE values of the composites indicated that the major factor that affects the CLTE of a composite is the filler content, but it also seems to be affected by the chemical structure of the matrix resin. TMA on water-saturated samples showed that water desorption takes place during the measurement and that the residual water acts as a plasticizer decreasing the T(g) and increasing the CLTE values. Furthermore, TMA on post-heated samples for 1, 3 or 6h showed, only for the resins, an initial decrease of CLTE and increase of the T(g) after 1h that was not significantly changed after 6h of heating.
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Papageorgiou GZ, Achilias DS, Karayannidis GP. Melting point depression and cocrystallization behavior of poly(ethylene-co-butylene 2,6-naphthalate) copolymers. POLYM INT 2004. [DOI: 10.1002/pi.1540] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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69
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Achilias DS, Sideridou ID. Kinetics of the Benzoyl Peroxide/Amine Initiated Free-Radical Polymerization of Dental Dimethacrylate Monomers: Experimental Studies and Mathematical Modeling for TEGDMA and Bis-EMA. Macromolecules 2004. [DOI: 10.1021/ma049803n] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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70
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Sideridou I, Achilias DS, Spyroudi C, Karabela M. Water sorption characteristics of light-cured dental resins and composites based on Bis-EMA/PCDMA. Biomaterials 2004; 25:367-76. [PMID: 14585725 DOI: 10.1016/s0142-9612(03)00529-5] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The water uptake characteristics of resins and composites based on an ethoxylated bisphenol A glycol dimethacrylate (Bis-EMA) and a polycarbonate dimethacrylate (PCDMA) were studied in detail. Polydimethacrylate resins were prepared by photopolymerization of the neat monomers and mixtures of them with various weight ratios, using the camphoroquinone/N,N-dimethylaminoethyl methacrylate system as initiator, while the composites were prepared from the light-curing of commercial samples (Sculpt-It and Alert). Water sorption/desorption was examined both in equilibrium and dynamic conditions in two adjacent sorption-desorption cycles. The equilibrium water uptake from all resins was very small with a trend to increase as the amount of PCDMA was increased. The inverse effect was observed in the solubility values. The composites studied exhibited also very low water uptake values in comparison to other composite materials reported in the literature. It was also observed that the equilibrium uptake decreased with increasing filler loading. Slightly larger equilibrium water uptake and much smaller solubility values were obtained during the second sorption-desorption cycle in comparison to the first one. Concerning the sorption rate data, it was observed that the resin materials followed Fickian diffusion during almost the whole sorption or desorption curve, while the composites showed this behavior until only M(t)/M( infinity ) congruent with 0.5. The diffusion coefficients calculated for the resins were larger than those of the composites and always higher during desorption compared to sorption. The values of the diffusion coefficients for both resins and composites were in the same order of magnitude with the values of the corresponding materials reported in the literature.
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Achilias DS, Papageorgiou GZ, Karayannidis GP. Isothermal and nonisothermal crystallization kinetics of poly(propylene terephthalate). ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20239] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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72
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Kiparissides C, Achilias DS, Frantzikinakis CE. The Effect of Oxygen on the Kinetics and Particle Size Distribution in Vinyl Chloride Emulsion Polymerization. Ind Eng Chem Res 2002. [DOI: 10.1021/ie010928f] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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73
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Achilias DS, Sideridou I. STUDY OF THE EFFECT OF TWO BPO/AMINE INITIATION SYSTEMS ON THE FREE-RADICAL POLYMERIZATION OF MMA USED IN DENTAL RESINS AND BONE CEMENTS. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2002. [DOI: 10.1081/ma-120016045] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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74
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Baltsas A, Achilias DS, Kiparissides C. A theoretical investigation of the production of branched copolymers in continuous stirred tank reactors. MACROMOL THEOR SIMUL 1996. [DOI: 10.1002/mats.1996.040050307] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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