| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Before investigating the effects of silane treatments of hybrid filler, the effects of concentrations of silane coupling agent and heat treatments of fillers were studied on the macrofiller (5.8mum).
At first, the mechanical properties of light activated composites using fillers treated with various concentrations (0.5-17%) of silane agent, i.e., gamma-MPTS,were examined. The compressive strength of experimental composites became maximum at 11% and the maximum diametral tensile strength was obtained at 8%. These concentrations corresponded to 50-70 molecules/100A^2.
In the second place, the effects of concentrations of silane agent (1,5,9,13%) and heat treatment temperatures (50,70,90,110,130ﾟC) of fillers were studied. Although the effect of heat treatment temperature was small in dilute solution (1%), the strength of composites containing fillers heated more than 110ﾟC became smaller with the increase of concentrations of silane. The composite containing the filler treated by 13% and h
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eated at 90ﾟC was the strongest.
Based on these results, the hybrid fillers were treated by varying next three factors, i.e., the figure of macrofiller (irregular or spherical), the contents of the microfiller (10-40%), and the sequence of mixing (fillers were mixed before/after silane treatment). The silane concentration was fixed at 9% against the filler weight and the heat treatment temperature was also fixed at 50ﾟC.
With regard to the figure of macrofiller, the composites containing the irregular macrofiller were stronger than those containing the spherical one. The composites utilizing hybrid fillers treated by silane agent after mixing the macrofiller and microfiller were stronger than those treated before mixing. The largest compressive strength was obtainedat 30% in microfiller contents. The compressive strength of composites containing the microfiller over 30% was decreased with the increase of microfiller contents. The diametral tensile strength was decreased with the increase of contents of microfiller. Less
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