| Stereolithography(SL) is the forming progress of the superposition when the photosensitive resins curing if exposured to the light . The modification of UV-curing resin was the main subject inveatigated in this paper.In SL, the photosensitive resins have direct effect on the dimensional accuracy, mechanical properties and thermal properties of the fabricated parts.At present there are some shortcomings in the fabricated parts such as bad transparency,bad surface quality,low hardness, bad toughness,low thermal stability. These insufficiencies have hindered further development of the photo-curing technology.Therefore, the developing of the superior materials for SL is meaningful and valuable.In the article nanometer SiO2 was filled in the photosensitive resin to enhance the mechanical property and thermal stability of fabricated parts .At first the modification of nanometer SiO2 was studied.Nanosilica was modified by different coupling agents.The effect of different modifiers and methods on hydrophobic stability of silica were studied.New groups on the surface of Nanosilica were characterized by FTIR,and the lipophilicity of the modified Nanosilica was tested.The results indicated that silicon responsed effectively with KH-560,and the hydrophobic stability of silica was greatly improved .The modified nanosilica was dispersed in the photosensitive resin,and nanosilica/UV curing resin composition was prepared.SEM experiment showed that silica nanoparticles were well dispersed in the resin. Property tests showed that modified parts had lower volume contraction and line contraction, hardness ,flexural strength,and toughness increased obviously,and thermal stability was also improved. The optimal proportion of nanosilica was 1%-2%.The parameter of photosensitive resin was tested.The result indicated the critical exposure increased , and the penetration depth becomed smaller after filled nanosilica,but there was little influence on cure of the photosensitive resin.
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