Optimum pressure for the high-pressure polymerization of urethane dimethacrylate
| Autor: | Anh Chi Phan, Jean-François Nguyen, Grégory Stoclet, N. Dorin Ruse, Pascal Béhin, Michaël Sadoun |
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| Rok vydání: | 2015 |
| Předmět: |
Materials science
Surface Properties Polyurethanes Benzoyl peroxide Composite Resins Viscoelasticity Polymerization Damping capacity Elastic Modulus Materials Testing Polymer chemistry Pressure medicine General Materials Science General Dentistry chemistry.chemical_classification Temperature Dynamic mechanical analysis Polymer UDMA Volume (thermodynamics) chemistry Chemical engineering Mechanics of Materials Methacrylates medicine.drug |
| Zdroj: | Dental Materials. 31:406-412 |
| ISSN: | 0109-5641 |
| DOI: | 10.1016/j.dental.2015.01.010 |
| Popis: | Objectives The aim of this study, part of our research to improve properties of resin composite blocks suitable for CAD/CAM and to better understand underlying mechanisms associated with high-temperature/high-pressure (HT/HP) polymerization, was to determine an optimum polymerization pressure of urethane dimethacrylate (UDMA) in the presence of an initiator (0.5% benzoyl peroxide) by determining the degree of conversion (DC) and viscoelastic properties of polymers obtained at 90 °C under varying HP. Methods DC and viscoelastic properties of 16 UDMA polymers, two controls (thermo-cured and thermo-cured followed by post-cure relaxation) and 14 experimental groups (HP polymers, in the range of 50–350 MPa, in 50 MPa increments, without and with post-cure relaxation) were determined via near infrared spectroscopic analysis and dynamic mechanical analysis, respectively. Results The results have shown that HP UDMA polymers have DC superior to that of the control group. With regards to E′ and E″, the results have shown no significant difference between control and HP polymers. The damping factor, tan δ, decreased with increasing pressure, while E ′ rub and Tg increased. Polymerization at 150 MPa or higher resulted in significantly higher E ′ rub and Tg. Significance The results of this study suggested that HP polymerization at 90 °C of UDMA reduced the number of defects and the free volume, leading to a more homogeneous polymer network. The results have also suggested that 200 MPa is an optimum polymerization pressure, resulting in polymers with significantly higher DC, E ′ rub , and Tg, while maintaining adequate damping capacity (tan δ). |
| Databáze: | OpenAIRE |
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