title: [Effect of nano ZrO2 on flexural strength and surface hardness of polymethylmethacrylate].
abstract: OBJECTIVE
  To study the effect of polymethylmethacrylate(PMMA's) mechanical properties reinforced by nano ZrO(2) particles with different filling amounts.
  
  
  METHODS
  The nano ZrO(2) particles were surface-treated by silane coupling agent(Z-6030) in 1.5wt% ratio, the untreated particles were regarded as the control group. The modified nano ZrO(2) particles were mixed with the PMMA powders in proportion of 0.5%,1%,1.5%,2%,2.5%,3% and 3.5%, respectively.Then the nano ZrO(2) /PMMA composites were synthesized. The specimens were examined by Vickers hardness test and three-point bending test, the surface of fracture was observed by SEM.All data were analyzed with ANOVA test by SAS 6.12 software package.
  
  
  RESULTS
  Fourier transform infrared(FTIR) spectroscopy showed that the silane coupling agent linked to the nano ZrO(2) particles' surface after treating,the Vickers hardness was highest when the adding amount of nano ZrO(2) particles was 1.5% and 2%(P<0.05).The flexural strength of nano ZrO(2)/PMMA composites in the proportion of 1.5% was the highest(P<0.05). SEM indicated that the ductile fracture existed on the surface of fracture.
  
  
  CONCLUSIONS
  The silane coupling agent can enhance the bonding strength of nano ZrO(2) particles and the PMMA matrix, the PMMA's mechanical properties could be improved by adding the nano ZrO(2) particle in an appropriate proportion. 1.5% and 2% of nano ZrO(2) particles render the nanocomposite the maximal Vickers hardness, while 1.5% ZrO(2) nanoparticles render the nanocomposite the maximal flexural strength.
authors: Department of Prosthodontics, Shanghai Jiao Tong University School of Medicine, Shanghai, China. xyinzhang@yahoo.com.cn
authors: Xin-jing
authors: XJ
authors: Zhang
authors: Xiu-yin
authors: XY
authors: Zhang
authors: Bang-shang
authors: BS
authors: Zhu
authors: Chen
authors: C
authors: Qian
mesh_terms: D006244:Hardness; D006801:Humans; D008422:Materials Testing; D018583:Pliability; D019904:Polymethyl Methacrylate; D012821:Silanes; D013499:Surface Properties
chemical_list: D012821:Silanes; D019904:Polymethyl Methacrylate