The elastic modulus of the 20 wt. The loss factor decreased over the entire frequency range with the incorporation of UFC. The neat TPER exhibited the lowest flexural strength The results of the TMOE and the flexural modulus of elasticity FMOE were in agreement with rheological data on complex viscosity, elastic modulus, and viscous modulus.
The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act or as modified by any successor legislation.
Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Additionally, the increased number of technique sensitive incremental steps required to fill relatively large cavities is due to inefficient light transmission at depths greater than 2 mm.
Accordingly, the change in optical properties and the setting reaction of RBC materials is not well understood. An interesting approach to control the setting reaction is by the application of the exposure reciprocity law.
Therefore the current investigation demonstrates the applicability of this law with regards to monomer composition, filler percentage and photoinitaitor type on degree of conversion with the aim of a better understanding of the setting reaction.
Although appropriate resin matrix chemistry and photoinitiator chemistry may provide potential for reduced curing time, inadequate cure depths remain without appropriate filler adaptation.
The development of techniques that will allow dynamic monitoring of optical and physical change during cure will further aid material development with the goal of improved depths of cure and will allow such restorations to be cured with one shot.
The current investigation has demonstrated the use of several analytical techniques FT-IR spectroscopy, UV-Vis Spectroscopy and low coherence interferometry which will aid such developments. UV-Vis spectroscopy and low coherence interferometry may have some significance towards a better understanding of the dynamic changes of optical properties of RBC materials.
UV-Vis Spectroscopy may be used to monitor the decomposition of the photoinitiator which will improve light transmission and low coherence interferometry can be used to monitor both refractive index and physical thickness change.
The current study demonstrated the complexity of optical phenomena within RBCs which are affected by material composition as well as cavity dimensions.
Whilst research continues to develop a novel RBC with reduced shrinkage and improved depths of cure, there is currently no commercially available solution to such problems.
Consequently a better understanding of the setting reaction, optical properties and physical properties will aid material development. I would like to extend my warmest thanks to Dr Palin for his continual encouragement, advice, guidance and patience which made this all possible.
I would also like to extend my gratitude to Dr Shortall for his aptitude for statistics throughout this PhD. I would like to express my gratitude to Dr P Tomlins and the National Physical Laboratory for all their support, advice and assistance in setting up Dynacure.
I would also like to express my gratitude to Mrs S Fisher and Dr J Wilson for their day to day technical assistance and to the administrative staff for their assistance dealing with the associated bureaucracy.
Finally, I would like to thank all my friends, family and postgraduate students for their support, patience and encouragement throughout this PhD, without whom this would truly be impossible. Dynamic monitoring of refractive index change through photoactive resins.
Dental Materials, ; Photoinitiator type and applicability of exposure reciprocity law in filled and unfilled photoactive resins. High irradiance curing and anomalies of exposure reciprocity law in resin-based materials.
Submitted to Journal of Dentistry. Competitive light absorbers in photoactive dental materials. Submitted to Acta Biomaterialia. Where other sources of information have been used, they have been acknowledged.
This thesis consists of two experimental Chapters with six sections in the form published and submitted papers with contributions from the following people other than the primary supervisors: Colour change value T: Change in temperature T Max: Maximum change in temperature Max DC: Maximum degree of conversion Max R p: Maximum rate of polymerisation R p: Analysis of variance BHT: Butylated hydroxy toluene Bis-GMA: Fourier-transform near infrared spectroscopy HF: Low coherence interferometry LF: Resin based composites RI: Page The chemical structure of the base and diluent monomers used in RBC materials.To evaluate the curing profile of bulk-fill resin-based composites (RBC) using micro-Raman spectroscopy (μRaman).
Rheological and Mechanical Properties of Ultra-fine Cellulose-Filled Thermoplastic Epoxy Composites Esra Erbas Kiziltas, a, b, * Alper Kiziltas, a, c and Douglas J. Gardner a Thermoplastic epoxy resin (TPER)-based composites containing different amounts of ultra-fine cellulose (UFC) were prepared via melt compounding and injection molding.
The replicating resin was a 75/25 blend of PHOTOMER (available from IGM Resins, Charlotte, NC) and hexanediol diacrylate with a photoinitator package comprising of % LUCRIN TPO (available from BASF Corp., Wyandotte, MI).
Preparation of advanced porous structures by stereolithography for application in. tissue engineering Ferry Melchels PhD thesis with references and summaries in English and Dutch. Influence of the photoinitiator system and light photoactivation units on the degree of conversion of dental composites ,1,2 or Lucirin TPO (2,4,6-trimethyl-benzoyldiphenylphosphine oxide), which has an absorption spectrum based composite resin is influenced not only by light intensity and wavelength, as emitted by the.
The use of resin based composites (RBCs) continues to increase at different rates internationally, partly due to the demise of amalgam. They provide a versatile and robust restoration material  , however, in recent years the biocompatibility of dental composite restorations has come into question .