Preparation And Mechanical Properties Of POSS Reinforced Denture Base Resin

Objective: In this investigation,we discussed the effect of POSS on the mechanical properties of denture base composite materials by testing the mechanical properties of the new POSS-PMMA nanocomposite.Methods: We prepared POSS under the protection of the nitrogen by the method of alternative synthesis.After measured 0.5wt%,1.0wt%,1.5wt%,2.0wt%,2.5wt%,3.0wt% by the electronic balance,POSS was added into MMA respectively and dispersed by the ultrasonic oscillation.We prepared the standard specimen by mixing them with PMMA by the ratio of 1:2,which were denoted by POSS adding group.We modified the nano-SiO₂ with a silane coupling agent(KH-570) and prepared the standard specimen in the same way,denoted by nano-SiO₂ adding group.We prepared the standard specimen according to clinical operations of mixing the monomer and denture base acrylic resin powder as the bank group.Nano-SiO₂, silanization nano-SiO₂ and POSS were characterized by the FTIR.We tested the impact strength,surface hardness and bearing of the blank group, POSS adding group and nano-SiO₂ adding group.The fractured impact strength specimen were shot and analysised by the Japan JSM-6700F scanning electron microscope with the voltage of 15KV. We used the software SPSS 17.0 for the statistical analysis of all the result data to compare the difference of different group.Combined with the literature,the characteristics of the POSS reinforced denture base composite materials and the effect of the POSS on the mechanical properties were discussed.Results:The results about the FTIR characterization of the test proved that part of KH-570 has been grafted to the nano-SiO₂,because the surface of alkylation nano-SiO₂ still had hydroxyl groups,therefore the performance of nano-SiO₂ reinforced denture base resin will have an impact. The absorption intensity of POSS chemical bonds were more then nano-SiO₂'s obviously,it proved that POSS's dispersion was better,POSS and PMMA have more stronger binding;Mechanical properties of the test results proved both of POSS and SiO₂ can improved the mechanical properties of denture base composite materials,but to improve the mechanical properties of denture base composite materials POSS was better than SiO₂. Impact strength test results proved that the impact strength of POSS add group was bigger than SiO₂ add group,the curves of numerical test goes first increased then down,when the POSS content in 2% the numerical to be the top,but no significant difference when 2%POSS compared with other groups(p>0.05);Surface hardness test results proved that the surface hardness of denture base composite materials was also first increased and then go down. The surface hardness of POSS add group was bigger than SiO₂ add group,when the POSS content in 2% the numerical to be the top and had significant difference when 2%POSS compared with other groups(p<0.05);Friction and wear test results proved that the friction and wear of denture base composite materials was also first increased and then go down. The friction and wear of POSS add group was bigger than SiO₂ add group,when the POSS content in 1.5% the numerical to be the top and had significant difference when 1.5%POSS compared with other groups(p<0.05).Conclusions: Compared with the nano-SiO₂ adding group,there were better interface of the two-phase and less particle agglomeration in the POSS adding group,which indicated that POSS could disperse better in PMMA.Therefore,the specimen strength and toughness were more excellent than the nano-SiO₂ adding group.