甲基丙烯酸偶联二氧化钛对自凝树脂机械性能的影响

Effect of methacrylic acid coupled TiO_2 on machanical properties of self-curing denture

目的:探讨纳米二氧化钛(TiO2)和甲基丙烯酸(MAA)偶联后活化的TiO2(F-TiO2)对聚甲基丙烯酸甲酯(PMMA)机械性能的影响。方法:选用颗粒径为510nm的TiO2及纯度为99.99%的MAA制备F-TiO2,采用傅立叶红外光谱(FT-IR)和X射线衍射图谱(XRD)对F-TiO2进行结构表征;采用原位聚合法制备TiO2/PMMA、F-TiO2/PMMA纳米复合树脂,根据偶联剂MAA的有无及TiO2质量比将试件分为空白组、2%TiO2组、4%TiO2组、6%TiO2组、2%F-TiO2组、4%F-TiO2组和6%F-TiO2组,并利用电子透射电镜(TEM)和电子万能试验机测试分析TiO2在PMMA基质中的分散性及各组纳米复合树脂的机械性能(挠度、弯曲强度、弹性模量和抗冲击强度)。结果:TEM观察,放大倍数为1 500倍时,添加纳米颗粒浓度为6%,TiO2较F-TiO2颗粒团聚明显,TiO2在PMMA基质中不均匀分散,F-TiO2在PMMA基质中均匀分散。机械性能测试,TiO2组与F-TiO2组试件的弯曲强度和抗冲击强度均随着TiO2质量比上升而下降,且随着TiO2质量比增大,试件弯曲强度降低;与6%TiO2组比较,6%F-TiO2组试件的弯曲强度和抗冲击强度明显增大(P<0.05)。TiO2质量比对弹性模量和挠度有明显影响,且随着TiO2质量比增大,TiO2组试件均表现出弹性模量逐渐降低但挠度升高的趋势,6%F-TiO2组试件弹性模量大于6%TiO2组;6%F-TiO2组试件(在压力为35和50N时)的挠度小于6%TiO2组(P<0.05)。结论:试件纳米TiO2复合树脂较自凝树脂的机械性能低,而MAA偶联剂可提高纳米TiO2复合树脂的机械性能。

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 The510 nm TiO2nanoparticles 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%TiO2group,4%TiO2group,and 6%TiO2group,2%F-TiO2 group,4%F-TiO2 group and6%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%TiO2group;the deflection of specimens（when the pressure was 35 and 50N）was lower than that in 6%TiO2group（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.