关键词: 甲基丙烯酸, 二氧化钛, 自凝树脂, 机械性能

Abstract:

Objective To study the effect of the functional titanium dioxide (F-TiO₂) on the mechanical properties of polymethyl methacrylate (PMMA) after nanoparticles TiO₂ coupled by methacrylic acid (MAA). Methods The 510 nm TiO₂ nanoparticles and MAA with the purity 99.99% were selected to prepare the F-TiO₂.The structural characteristics of F-TiO₂ were tested by using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Then TiO₂/PMMA and TiO₂/PMMA nanocomposites were constructed through in situ polymerization method. According to the existence of MAA and the quality ratios of TiO₂ added inside,these samples were divided into control group,2%TiO₂ group,4%TiO₂ group,and 6%TiO₂ group,2%F-TiO₂ group,4%F-TiO₂ group and 6%F-TiO₂ group.Transmission electron microscope(TEM) and electronic universal testing machine were utilized to evaluate the TiO₂ dispersion in the PMMA matrix and the mechanical properties of nano-composite resin (deflection,bending strength,flexure modulus and impact strength). Results The TEM (×1 500) results showed that in 6% groups the agglomeration of TiO₂ nanoparticles were more obvious than that in F-TiO₂ group,and a better dispersion of F-TiO₂ nanoparticles was observed in PMMA matrix.The mechanics assay showed a descending trend of self-curing resin's flexure strength and impact strength with the increase of TiO₂ quality ratios.Compared with 6% TiO₂ group,the flexure strength and impact strength of the specimen in 6% F-TiO₂ group were increased apparently (P<0.05).The TiO₂ quality ratios had a significant influence in the flexure modulus and deflection; with the increasing of quality ratios of TiO₂, the flexure modulus of the specimen in TiO₂ groups showed a descending trend.The flexure modulus of specimen in 6% F-TiO₂ group was higher than that in 6%TiO₂ group;the deflection of specimens (when the pressure was 35 and 50 N) was lower than that in 6%TiO₂ group(P<0.05). Conclusion Compared with single self-curing resin,the nano TiO₂-resin composites are characterized by poor mechanical properties, but this weakness can be compensated by methacrylic acid coupling agent.

Key words: methacrylic acid, titanium dioxide, self-curing resin, mechanical properties