Original scientific paper
Investigation of the Effect of Variation of Cross- Linking Agents and two Heating Rates on Glass Transition of a Denture Base Acrylic Resin
Vjekoslav Jerolimov
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Robert G. Jagger
; Department of Restorative Dentistry School of Dentistry, University of Wales College of Medicine, Cardiff, Wales, Velika Britanija
Paul J. Millward
; Department of Restorative Dentistry School of Dentistry, University of Wales College of Medicine, Cardiff, Wales, Velika Britanija
Vlado Carek
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Abstract
The purpose of the study was to investigate the effect of two different
heating rates used in order to evaluate the transition glass temperature of dough-moulded poly (methylmethacrylate) denture base materials. Cross-linking agents ethylene glicol dimethacrylate (EGDMA), tetra (ethylene glycol dimetacry late) (TEGDMA) and poly (ethylene glycol dimethacrylate) (PEG 600 DMA) were added to the MM A monomer component in concentrations o f 0 - 30% according to the volume o f monomer liquid concentration. The polymer component was an unpigmented PMMA homopolymer. The comparison group of specimens was made by using the monomer liquid without a cross-linking agent. Specimens were produced in moulds according to conventional dental- flasking and curing procedures. Measurements o f Tg were determined by thermomechanical analysis using a Stanton Redcroft TMA, Model 790 (PL Thermal Sciences Ltd., Epsom, UK) Heating rates o f 5 °C/min and 10 °C/min were selected for this investigation. It was concluded that Tg values were highly dependent o f the heating rates used in thermomechanical analysis, being very significantly increased with the increase in heating rate. It was also concluded that the addition of a cross-linking agent would affect Tg o f denture base resins.
Keywords
poly(methyl methacrylate); glass transition; heating rate; cross-linking
Hrčak ID:
99348
URI
Publication date:
15.3.1997.
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