Posts Tagged ‘urethane’

Product Spotlight: EXOTHANE ACRYLATES

Wednesday, September 12th, 2012
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EXOTHANE(tm) ELASTOMERS

Product Code: X-991-0000

Synonyms:  EXOTHANE 108

Exothane 108 is the acrylate analog of our Exothane 8.  It shares similar properties to Exothane 8 such as enhanced toughness, high percent elongation and good tensile strength but, cures much faster.

 

Product Code: X-992-0000

Synonyms:  EXOTHANE 126

Exothane 126 is the acrylate analog of Exothane 126.  When cured “neat”, Exothane 126 has very high conversion and very low shrinkage.  The resulting homopolymer is very soft and rubber-like.

 

We are constantly developing more Exothanes to meet your applications!  Email us to request samples or discuss custom synthesis, techsupport@esstechinc.com

 

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Urethane Dimethacrylate used in Rapid Prototyping Application

Thursday, October 13th, 2011
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Characterization of a nanoparticle-filled resin for application in scan-LED-technology

Eva Kolb, Claudia Kummerlöwe and Martin Klare

Volume 22, Number 10, 2165-2173, DOI: 10.1007/s10856-011-4411-7

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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Introducing EXOTHANE Elastomers

Wednesday, September 28th, 2011
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EXOTHANE Elastomers

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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FIT 852 Shrinkage / Conversion Data

Thursday, July 28th, 2011
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Click on the following link for a pdf download of our poster.

Physical Properties of a New Low Shrink Resin

A. JOHNSTON1, F. RUEGGEBERG2, H.R. RAWLS3, H. SLAFF1, T. BARCLIFT1, and J. DUFF1, 1Esstech Inc, Essington, PA, 2Medical College of Georgia, Augusta, GA, 3University of Texas Health Science Center at San Antonio, San Antonio, TX

Introduction:

The improvement of aesthetic restorative dental composites can be pursued on many fronts. A composite is made from multiple components but, generally, it is a blend of finely ground glasses and reactive monomers.  The monomers cure to provide a continuous polymer matrix for retaining the glass.  Together they present a hard surface with the capability to survive in the oral environment.  Failure of these composites is a complex phenomenon.   While clinical failure can occur when the adhesive force between the composite and the vital dental tissue is compromised, failure also occurs when stresses overcome the cohesive strength of the continuous phase of the mixture.   Catastrophic material failure can occur as wear against complementary dentition that slowly erodes the surface.   Those cracks through the polymer phase lead to composite failure.  To improve the composite properties, a new monomer has been introduced, FIT 852 Resin™, that can provide greater toughness in the polymer, greater extent of cure in the polymer, lower shrinkage stress and no change in composite material manufacture.


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X-726-0000, Suitable HEMA Replacement

Tuesday, July 5th, 2011
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A new approach in self-etching adhesive formulations: Replacing HEMA for surfactant dimethacrylate monomers

Cesar Henrique Zanchi,, Eliseu Aldrighi Münchow, Fabricio Aulo Ogliari, Rodrigo Varella de Carvalho, Stefano Chersoni, Carlo Prati, Flávio Fernando Demarco, Evandro Piva

Article first published online: 28 JUN 2011.  DOI: 10.1002/jbm.b.31871. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.

Abstract

This study evaluated the influence of surfactant dimethacrylates (SD) on the resin-to-dentin microtensile bond strength (μTBS) and characterized the interfacial micromorphology of the hybrid layer of the experimental HEMA-free self-etching systems. Five experimental HEMA-free two-step self-etching systems containing different SD (Bis-EMA 10, Bis-EMA 30, PEG 400, PEG 1000, and PEG 400 UDMA [Esstech Code X-726-0000]) and a HEMA-containing system (control) were compared. Each experimental adhesive system was applied and resin composite restorations were incrementally built up in bovine incisors. After 24 h, restored teeth were sectioned to obtain 24 sticks per group. Thereafter, the specimens were subjected to the μTBS test. Data (MPa) were analyzed by One-way ANOVA and Tukey’s test. Adhesive-dentin interfaces were analyzed through Scanning Electron Microscopy (SEM). The adhesive system formulated with PEG 400 UDMA produced μTBS similar to the HEMA-containing group and statistically higher than the HEMA-free groups. Similar failure percentages were observed in the PEG 400 UDMA and the control group. In the SEM analysis, all the adhesive systems presented similar partially demineralized hybrid layer (1.5–3.0 μm thickness) with well-formed resin tags. All SD presented reasonable initial μTBS, with the PEG 400 UDMA being a promising monomer to be considered as a HEMA substitute in adhesive systems compositions.


Link:  http://onlinelibrary.wiley.com/doi/10.1002/jbm.b.31871/full

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BisGMA – UDMA Composite with Nanosilica Fibers

Tuesday, March 29th, 2011
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Synthesis of Nanosilica Fillers for Experimental Dental Nanocomposites and Their Characterisations
Tuan Noraihan Azila Tuan Rahim1, Dasmawati Mohamad1*, Abdul Rashid Ismail1 and Hazizan Md Akil2

1School of Dental Sciences, Universiti Sains Malaysia,
2School of Material and Mineral Resources Engineering, Universiti Sains Malaysia

MATERIALS:

Tetraethyorthosilicate (TEOS), absolute ethanol, ammonia,  γ-methacryloxypropyl-trimethoxysilane (γ-MPS), acetic acid (CH3COOH), bisphenol A glycidyl methacrylate (BisGMA, Esstech), diurethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGDMA), camphorquinone (CQ), (2-dimethylaminoethyl) methacrylate (DMAEMA) and distilled water were used in this work. The chemicals were employed without any further purification.

ABSTRACT:

The aim of this study was to synthesise nanosilica fillers for use in the fabrication of experimental dental nanocomposites and to evaluate their properties,  including surface and mechanical properties. Monodispersed, spherical silica nanoparticles were synthesised via a sol-gel process, and a size range of 10–20 nm was obtained. Surface treatment of the nanosilica was carried out with the silane coupling agent γ-methacryloxypropyltrimethoxysilane (MPS) to reduce agglomeration of nanosilica. Experimental dental nanocomposites with two different filler contents, 30 and 35 wt%, were fabricated and polymerised with a light curing unit for 40 s. The surface morphology, surface roughness, flexural strength and elastic modulus were evaluated and compared. A nanocomposite with 35% filler content showed higher filler compaction, lower surface roughness and higher elastic modulus than a nanocomposite filled with 30% filler. However, the nanocomposite filled with 30% filler content showed higher flexural strength. Based on the results obtained, the synthesised nanosilica is a promising material for the fabrication of dental nanocomposites for tooth-filling applications.



LINK:  http://web.usm.my/jps/22-1-11/22.1.6.pdf


Journal of Physical Science, Vol. 22(1), 93–105, 2011
© Penerbit Universiti Sains Malaysia, 2011

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Properties of UDMA and Bis-GMA based Composites

Monday, February 28th, 2011
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Hydrogen bonding interactions in methacrylate monomers and polymers

Marianela T. Lemon, Melissa S. Jones, Jeffrey W. Stansbury
Department of Craniofacial Biology, University of Colorado School of Dentistry, Aurora, Colorado 80045

ABSTRACT

It is well appreciated that hydrogen bonding affects a variety of monomer and polymer properties. This study focused on Bis-GMA and urethane dimethacrylate (UDMA) to help elucidate how the strength and nature of
specific noncovalent interactions involved with these different functional dimethacrylate structures are expressed in the monomers and polymers. Hydrogen bonding interactions in monomers and comonomer mixtures as well as in appropriate model compounds were examined by FT-IR under ambient conditions, at elevated temperatures and in dilution studies. The investigation of hydrogen bonding extended to monomer viscosity, photopolymerization reaction kinetics, and polymer mechanical properties.

CONCLUSION

The strength of hydrogen bonding was shown not only to be greater for Bis-GMA compared with UDMA, but there is also greater contribution from intermolecular interactions that enhance the hydrogen bonding effects. While UDMA-based polymers reach significantly higher levels of conversion compared with Bis-GMA materials, the stronger hydrogen bonding reinforcement associated with Bis-GMA appears to provide for comparable mechanical strength properties. Depending on the hydrogen bond donor functionality of a monomer as well as its neighboring functional groups, overall monomer structure and comonomers used, hydrogen bonding can favorably affect polymerization reactivity and mechanical properties, even in materials that form highly crosslinked polymeric networks.


Wiley Periodicals, Inc. J Biomed Mater Res 83A: 734–746,2007

Link:  http://onlinelibrary.wiley.com/doi/10.1002/jbm.a.31448/abstract



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An Overview of Esstech, Inc.

Tuesday, August 10th, 2010
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UDMA – TEGDMA Viable Resin System for Chlorhexidine Release

Thursday, June 17th, 2010
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Controlled Release of Chlorhexidine from UDMA-TEGDMA Resin

K.J. Anusavice, N.-Z. Zhang and C. Shen

J DENT RES 2006; 85; 950

ABSTRACT
Chlorhexidine salts are available in various formulations for dental applications. This study tested the hypothesis that the release of chlorhexidine from a urethane dimethacrylate and triethylene glycol dimethacrylate resin system can be effectively controlled by the chlorhexidine diacetate content and pH. The filler concentrations were 9.1, 23.1, or 33.3 wt%, and the filled resins were exposed to pH 4 and pH 6 acetate buffers. The results showed that Fickian diffusion was the dominant release mechanism. The rates of release were significantly higher in pH 4 buffer, which was attributed to the increase of chlorhexidine diacetate solubility at lower pH. The higher level of filler loading reduced the degree of polymerization, leading to a greater loss of organic components and higher chlorhexidine release rates.

Link:  http://jdr.sagepub.com/cgi/content/abstract/85/10/950


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Bisphenol A Content

Wednesday, June 2nd, 2010
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BisGMA, bisphenol A-glycidyl methacrylate is a common resin that carries trace amounts of BPA.  Bisphenol A (BPA) carries with it various risks recognized by the National Toxicology Program.

It is possible that high doses of bisphenol A during pregnancy and/or lactation can reduce survival, birth weight, and growth of offspring early in life.  BPA has also been shown to have estrogenic effects. *

According to internal analysis, Esstech’s bisGMA, Product Code X-950-0000, has one of the lowest BPA concentrations in the industry.

BPA Chart

EASE OF FORMULATION

To simplify formulations, X-950-0000 is available in pre-mixed solutions with Triethyleneglycol Dimethacrylate (TEGDMA).

BPA-FREE ALTERNATIVES

Esstech is constantly striving to provide customers with the most up-to-date and novel materials.  The f0llowing are resin “alternatives” that do not contain BPA.

X-850-0000, Urethane Dimethacrylate

  • Cures to create a hard glassy surface
  • Low color values
  • Excellent compatibility with light cure systems

X-726-0000, Extended UDMA

  • Increased flexibility
  • Enhanced fracture toughness

Esstech is constantly striving to provide customers with the most up-to-date and novel materials.  Contact us if you would like to discuss a certain material or to hear what we have in development.

* NTP-CERHR Monograph on the Potential Human Reproductive and Developmental Effects of Bisphenol A.  National Toxicology Program, U.S. Department of Health and Human Services.  NIH Publication No. 08-5994, September 2008.


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