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From its simple origins in the early 1990′s as a line of highly customized raw materials for compounders of “new generation” restorative dental composites to now a major manufacturer of customized UV/EB curable materials serving an ever-wider range of industries, Esstech, Inc. has indeed been a very successful “experiment”. It is my pleasure to announce two additions to the Esstech Team of talented professionals.
Last year, Bruce Farina, a 21-year veteran of Sartomer Company, joined Esstech as Senior Vice President and we are now pleased to announce that, effective as of January 1, 2012, Bruce has been given full operational responsibility for Esstech as President/COO. Bruce’s two decades of experience at Sartomer ranged from Manufacturing Manager through various titles and functions to Vice President with, most recently, overall global responsibility for all of Sartomer’s photocure (UV/EB) business.
Bruce is taking over for Howard Slaff who, after a very successful leadership tenure at Esstech, is moving ten miles south down I-95 to assume the President/COO responsibilities being vacated by the retiring Mike Norquist at Esstech’s sister company, Esschem, Inc..
I am also very pleased to announce that Bruce has successfully recruited Dr. Mike Idacavage as Esstech’s new Director of Business Development. Mike Idacavage may be known to some of you as the immediate past-President of RadTech North America and is a lifetime member of RadTech’s Board of Directors. Mike’s “day job” for the last 15 years was with Cytec Industries (and, pre-merger, UCB Chemicals), most recently as Cytec’s Principal Research Fellow.
Those of us involved with Esstech over the years could not be more excited with the Team now in place and with their commitment to its next phase of customer-centric growth!
Please check us out at www.esstechinc.com !
Henry M. (“Tac”) Justi
Chairman
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Curing efficiency of dental resin composites formulated with camphorquinone or trimethylbenzoyl-diphenyl-phosphine oxide
Luis Felipe J. Schneider, Larissa Maria Cavalcante, Scott A. Prah, Carmem S. Pfeifer, Jack L. Ferracane. “Curing efficiency of dental resin composites formulated with camphorquinone or trimethylbenzoyl-diphenyl-phosphine oxide” Dental Materials. December 2011: Online
Summary:
This research presents trimethylbenzoyl-diphenyl-phosphine oxide (TPO) as an alternative to camphorquinone (CQ) photoinitiator systems for dental resins. An immediate advantage is the low color of TPO in comparison to the strong yellow color of CQ. Testing using a spectrophotometer and differential scanning calorimetry (DSC) revealed that TPO had higher reactivity than CQ. CQ exhibited higher absorbed power density, (PDabs) and better depth of cure.
Materials
Testing of each photoinitiator was performed using 50:50 formulations of 2,2-bis[4-2(2-hydroxy-3-
methacroyloxypropoxy)phenyl]propane (Bis-GMA, Esstech) and triethyleneglycol dimethacrylate (TEGDMA, Esstech).
LINK: http://dx.doi.org/10.1016/j.dental.2011.11.014
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Join us in Sau Paulo for the CIOSP dental show, January 28-31.
We are planning a very exciting and busy trip so contact us immediately to schedule a meeting.
Hope to see you there!
Micro-Raman spectroscopic analysis of the degree of conversion of composite resins containing different initiators cured by polywave or monowave LED units
Vesna Miletic a, Ario Santini b,
a Clinical Lecturer, University of Belgrade, School of Dentistry, Department of Restorative Odontology and Endodontics, Rankeova 4, Belgrade, Serbia
b Director of Biomaterials Research, The University of Edinburgh, Edinburgh Postgraduate Dental Institute, Lauriston Place, Edinburgh EH3 9HA, United Kingdom
Received 20 August 2011; revised 28 October 2011; Accepted 30 October 2011. Available online 6 November 2011.
Objectives
To determine the degree of conversion (DC) over 48 h post-curing of resin mixtures containing trimethylbenzoyl-diphenylphosphine oxide (TPO) initiator cured by a polywave or a monowave LED light-curing unit (LCU).
Methods
In resin mixtures based on equal weight percent (wt%) of BisGMA and TEGDMA the following initiators were added: 0.2wt% camphorquinone (CQ) + 0.8wt% ethyl-4-dimethylaminobenzoate (EDMAB) (Group 1); 1wt% TPO (Group 2) and 0.1wt% CQ + 0.4wt% EDMAB + 0.5wt% TPO (Group 3). Half of the samples in each group (n = 5) were cured using a polywave (bluephase® G2, Ivoclar Vivadent) or a monowave LED LCU (bluephase®, Ivoclar Vivadent). The DC was measured using micro-Raman spectroscopy within 5 min and then 1, 3, 6, 24 and 48 h post-irradiation. The data were analyzed using general linear model and two-way ANOVA for the factors ‘time’, ‘material’, ‘surface’ and ‘LCU’ at α=0.05.
Results
The initial DC values obtained upon light curing remained similar over a 48 h period. bluephase® G2 produced the highest DC in Group 2 followed by Group 3, and Group 1. bluephase® resulted in the highest DC in Group 1, followed by Group 2 and Group 3 (p < 0.05).
Conclusions
Unfilled resin materials containing both TPO- and CQ-amine initiators are effectively cured using bluephase® G2. Resin mixture with the same wt% of initiators is better cured when TPO is the only initiator, compared to CQ-amine only or combined TPO and CQ-amine system. After initial light cure, no additional conversion of uncured monomers was detected in an unfilled resin material over 48 h at 37 °C.
Materials
… Page 5 of 24 Ac ce pte d M an usc rip t 4 Materials and Methods The following materials were
used in the study: bisphenol A bis(2-bydroxy-3- methacryloxypropyl)ether (BisGMA), triethylene
glycol dimethacrylate (TEGDMA), camphorquinone (CQ) (Esstech Inc, Essington, PA …
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Do not sacrifice conversion and the risk of residual monomer contamination to achieve low-shrink properties. New testing has demonstrated that EXOTHANE(TM) Elastomers have low shrinkage stress, low volumetric shrinkage, AND high conversion.
- Exothane 8, 94% Conversion, 3% Shrinkage, high % elongation
- Exothane 26, 96% Conversion, 4% Shrinkage, increased flexibility/toughness
- Exothane 32, 97% Conversion, 3% Shrinkage, low color and low viscosity
This new data, in addition to superior toughness, tensilse strength and percent elongation make the EXOTHANE product line ideal form many applications including, low-shrink dental restoratives, non-curling industrial coatings, unique UV nail enhancements, tougher anaerobic adhesives and more.
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Item Code: X-846-0000
Product Name: Methacryloyloxyethyl Maleate
CAS#: 51978-15-5
EINECS(I): 257-569-5
INCI: HEMA Maleate
HEMA maleate is a carboxylic acid-containing methacrylate that can function as an alternative to PMDM. It has been used in anaerobic adhesive applications and is approved for use in cosmetic products.
The carboxylic acid group of X-846-0000 has the ability to improve adhesion to keratin. Its’ monomethacrylate functionality allows it to be incorporated into soak-off systems without detriment to “removability”. HEMA maleate’s low viscosity also makes it an ideal, reactive diluents.
Contact us directly to discuss your application and request samples, techsupport@esstechinc.com.
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Characterization of a nanoparticle-filled resin for application in scan-LED-technology
Eva Kolb, Claudia Kummerlöwe and Martin Klare
Abstract
Scan-LED-technology is a new rapid prototyping technique with increasing applications in the production of custom-made medical products. The present work is dealing with the examination of a silica/ urethandimethacrylate (UDMA) nanocomposite for application in scan-LED-technology. The use of specific LED in a photo-DSC unit enables the simulation of crucial parameters of nanoparticle-filled resins for their application in scan-LED-technology. The conversion of double bonds during the curing reaction and the rate of conversion were studied as a function of radiation intensity, silica nanoparticle content, and silanization of the nanoparticles with 3-methacryloyloxypropyl-trimethoxysilane (MPTMS). The conversion of double bonds is increasing with increasing radiation intensity. The increasing conversion of the nanoparticle-filled resins is discussed as a combined effect of increasing nanoparticle content, alternated initiator/double bond ratio and increasing radiation intensity. A significant dependence of the reaction rate on nanoparticle content could not be found. Only for the unfilled resin, the rate was increasing at higher radiation intensities. The influence of residual solvent on conversion and rate of reaction was also analyzed. TGA measurements combined with FTIR were used to study the silanization of the nanoparticles. The silane layer thickness on the surface of the silica nanoparticles was determined. -
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Optimize Photocurable Mechanical Properties
EXOTHANE™ Elastomers represent the most recent advances in Esstech’s urethane chemistry. These versatile materials offer performance enhancements across a broad range of demanding formulations.
- Exothane 8, low color urethane, creates a “soft” yet tough polymer with high elongation
- Exothane 26, high flexibility when cured, has the ability to re-adhere at lower tensile strength
- Exothane 24, high crosslink capacity, low in color and viscosity and very high Shore D hardness
- Exothane 32, very low in color and viscosity, provides improved flexibility
Like many of Esstech’s other products, potential applications involving EXOTHANE™ Elastomers can vary across many industries from medical devices and nail gel enhancements to radiation-curable coatings.
Contact us directly to discuss your unique requirements and request our EXOTHANE™ Elastomers Product Literature.
Phone: 1-800-245-3800 or 610-521-3800
EMail: techsupport@esstechinc.com.
Esstech products are available to our European customers via, Esschem Europe
(www.esschem-europe.com).
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Esstech will be attending the UV.EB East Show in Syracuse, NY from October 4th to the 5th.
We look forward to seeing everyone, making appointments and discussing our new EXOTHANE(TM) Elastomers product line .
If you would like to schedule a meeting with use, please send an email to techsupport@esstechinc.com.
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Influence of the base and diluent methacrylate monomers on the polymerization stress and its determinants
N. R. G. Fróes-Salgado, L. C. Boaro, B. Pick, C. S. Pfeifer, C. E. Francci, M. M. Méier, R. R. Braga. Journal of Applied Polymer Science.
Overview:
The correct pairing of methacrylate diluents and resins can optimize properties like polymerization stress, volumetric shrinkage, degree of conversion, maximum rate of polymerization, and elastic modulus in composite formulations.
Abstract:
The aim of this study was to evaluate the effect of the association between bisphenol-A diglycidyl dimethacrylate (BisGMA) or its ethoxylated version (BisEMA) with diluents derived from the ethylene glycol dimethacrylate (EGDMA), with increasing number of ethylene glycol units (1: EGDMA, 2: DEGDMA, 3: TEGDMA, or 4: TETGDMA), or trimethylol propane trimethacrylate (TMPTMA) or 1,10-decanediol dimethacrylate (D3MA) on polymerization stress, volumetric shrinkage, degree of conversion, maximum rate of polymerization (Rpmax), and elastic modulus of experimental composites. BisGMA containing formulations presented lower shrinkage and stress but higher modulus and Rpmax than those containing BisEMA. TMPTMA presented the lowest stress among all diluents, as a result of lower conversion. EGDMA, DEGDMA, TEGDMA, and TETGDMA presented similar polymerization stress which was higher than the stress presented by D3MA and TMPTMA. D3MA presented similar conversion when copolymerized with both base monomers. The other diluents presented higher conversion when associated with BisEMA. EGDMA showed similar shrinkage compared with DEGDMA and higher than the other diluents. The lower conversion achieved by TMPTMA did not jeopardize its elastic modulus, similar to the other diluents. Despite the similar conversion presented by D3MA in comparison with EGDMA and DEGDMA, its lower elastic modulus may limit its use. Rather than proposing new materials, this study provides a systematic evaluation of off the shelf monomers and their effects on stress development, as highlighted by the analysis of conversion, shrinkage and modulus, to aid the optimization of commercially available materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
LINK: http://onlinelibrary.wiley.com/doi/10.1002/app.34947/full
Article first published online: 1 SEP 2011. DOI: 10.1002/app.34947
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