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Posts Tagged ‘Methacrylate’
Optimizing Degree of Conversion, Strength, Young’s Modulus and Hardness of Bis-EMA, Bis-GMA and TEGDMA Formulations
Tuesday, April 20th, 2010
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Preparation and Evaluation of Dental Resin Luting Agents with Increasing Content of Bisphenol-A Ethoxylated Dimethacrylate
Rafael R. Moraes, Mário A.C. Sinhoreti, Lourenço Correr-Sobrinho, Fabrício A. Ogliari, Evandro Piva, and Cesar L. Petzhold
Journal of Biomaterials Applications, Jan 2010; vol. 24: pp. 453 – 473.
Abstract: Resin luting agents in which bisphenol-A glycidyl dimethacrylate (Bis-GMA) and/or triethylene glycol dimethacrylate (TEGDMA) are replaced with increasing amounts of bisphenol-A ethoxylated dimethacrylate are prepared. Degree of conversion (DC), diametral tensile strength (DTS), Young’s modulus (YM), Knoop hardness (KHN), film thickness (FT), water sorption (Wsp ), and solubility are evaluated. Regression analyses investigate the substitution of each monomer. The most appreciable differences are detected when TEGDMA is replaced: decreased DC, DTS, and Wsp, and increased YM, KHN, and FT. For substitution of Bis-GMA, the only significant differences are reduced Wsp and increased YM. An ideal formulation of resin cement would make use of the three monomers.
…Bis-GMA, TEGDMA, and/or Bis-EMA (Esstech Inc., Essington, PA, USA) were tested…photo-curable, 0.4 wt% of camphor- quinone (Esstech) and 0.8 wt% of N,N-dimethyl-p-toluidine…silanated strontium glass fillers (Esstech), 0.7 and 2 mm in size, to a constant…
This version was published on January 1, 2010.
Link: http://jba.sagepub.com/cgi/content/abstract/24/5/453
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Refractive Index of Methacrylate Monomers & Polymers
Thursday, March 11th, 2010
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TECHNICAL BULLETIN: Refractive Index of Monomers and Their Respective Polymers
The refractive index (RI) of photopolymers is an essential property for many applications. For optical and coating applications, the RI can be related to the resultant gloss or clarity upon cure. Within the dental industry, the refractive index of the organic polymer matrix, must match that of the inorganic filler and substrate in order to avoid obvious “lines” where the product is applied.
Various factors affect refractive index values. The presence of conjugated ring structures contributes to increasing RI. In general, larger molecular weight monomers have a tendency to possess a higher RI in comparison to their lower molecular weight counterparts. Similar to this trend, high molecular weight functional groups like methacrylates have higher RI than their acrylate counterparts. Higher atomic weight atoms also seem to be predisposed to having higher RI.
Recognizing the importance of refractive index to our customers, Esstech has assembled RI data for a portion of our existing monomer products as well as their corresponding homopolymers.
Maintaining its position as an industry innovator, Esstech has also created functional, high refractive index materials. Contact us to learn more about these novel materials and how Esstech can make a material to match your application.
(P) 800-245-3800 / (P) 610-521-3800 / techsupport@esstechinc.com / www.esstechinc.com
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