后拉伸 PAN-PMMA 纳米纤维增强和增韧 Bis-GMA 牙科修复复合材料。
Post-draw PAN-PMMA nanofiber reinforced and toughened Bis-GMA dental restorative composite.
机构信息
The Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer, Beijing University of Chemical Technology, Beijing 100029, PR China.
出版信息
Dent Mater. 2010 Sep;26(9):873-80. doi: 10.1016/j.dental.2010.03.022. Epub 2010 Jun 26.
OBJECTIVES
The polyacrylonitrile (PAN)-poly(methyl methacrylate) (PMMA) core-shell nanofiber reinforced dental composites have been investigated for their excellent interface adhesive, and this kind of novel dental composite has the potential for clinical uses such as denture base resin and crown-bridge material. The first objective of this work was to determine the improving effect of tensile properties by post-drawing PAN-PMMA nanofibers membrane. The second objective was to examine the flexural strength (Fs), flexural modulus (Ey) and work of fracture (WOF) of Bis-GMA/TEGDMA composites reinforced with PAN-PMMA nanofibers.
METHODS
PAN(core)-PMMA(shell) nanofiber was made by an electrospinning setup with a high-speed rotating rod-like collector. The post-draw process was carried out at 120 degrees C for 5 min, and all the nanofiber membranes were elongated to the desired elongation ratio (30%, 60% or 100%). Tensile properties and flexural properties of both nanofiber membranes and nanofiber reinforced Bis-GMA/TEGDMA composites were investigated. A scanning electron microscope (SEM) was used to observe the fiber morphology and the fracture surface of the composite. A dynamic mechanical thermal analyzer (DMTA) was employed to determine the dynamic mechanical properties such as tandelta and E'.
RESULTS
The post-drawing treatment significantly improved the tensile properties and fiber parallelism of nanofiber membranes. The addition of PAN-PMMA nanofibers into Bis-GMA/TEGDMA clearly showed the reinforcement effect; the flexural strength (Fs), flexural modulus (Ey) and work of fracture (WOF) kept rising with the nanofiber mass fraction changing from 0%, 0.6%, 0.8%, 1.0% to 1.2%. The flexural properties of composites reinforced with post-drawn nanofiber were further increased in comparison with those of untreated nanofiber reinforced ones. Also, the SEM observations of the fracture surface of the composites demonstrated good interfacial adhesion between fibers and resin.
SIGNIFICANCE
The post-drawing treatment was confirmed as a useful method for significantly increasing the tensile strength (673.4%) and tensile modulus (875.3%) of nanofiber membranes. In addition, the composites reinforced with post-drawn PAN-PMMA nanofibers exhibited higher Fs (13.6%), Ey (5.3%) and WOF (30.4%) than those reinforced with as-electrospun PAN-PMMA nanofibers. When 1.2% mass fraction of post-drawn nanofibers were added to Bis-GMA/TEGDMA resin, the Fs, Ey and WOF increased by 51.6%, 64.3% and 152.0%, respectively, compared with neat resin.
目的
聚甲基丙烯酸甲酯（PMMA）-聚丙烯腈（PAN）核壳纳米纤维增强牙科复合材料具有优异的界面粘结性能，这种新型牙科复合材料具有临床应用的潜力，如义齿基托树脂和冠桥材料。这项工作的首要目标是确定后拉伸 PAN-PMMA 纳米纤维膜对拉伸性能的改善效果。其次是研究 PAN-PMMA 纳米纤维增强 Bis-GMA/TEGDMA 复合材料的弯曲强度（Fs）、弯曲弹性模量（Ey）和断裂功（WOF）。
方法
采用高速旋转棒状收集器的静电纺丝装置制备 PAN（核）-PMMA（壳）纳米纤维。后拉伸过程在 120°C 下进行 5 分钟，所有纳米纤维膜均被拉伸至所需的伸长率（30%、60%或 100%）。测试了纳米纤维膜和纳米纤维增强 Bis-GMA/TEGDMA 复合材料的拉伸性能和弯曲性能。使用扫描电子显微镜（SEM）观察纤维形态和复合材料的断裂表面。采用动态力学热分析仪（DMTA）测定了复合材料的动态力学性能，如 tanδ和 E'。
结果
后拉伸处理显著提高了纳米纤维膜的拉伸性能和纤维平行度。添加 PAN-PMMA 纳米纤维到 Bis-GMA/TEGDMA 中明显显示出增强效果；随着纳米纤维质量分数从 0%、0.6%、0.8%、1.0%变为 1.2%，弯曲强度（Fs）、弯曲弹性模量（Ey）和断裂功（WOF）不断增加。与未经处理的纳米纤维增强复合材料相比，经后拉伸纳米纤维增强的复合材料的弯曲性能进一步提高。此外，复合材料断裂表面的 SEM 观察表明纤维与树脂之间具有良好的界面粘结。
意义
后拉伸处理被证实是一种有效方法，可以显著提高纳米纤维膜的拉伸强度（673.4%）和拉伸模量（875.3%）。此外，添加后拉伸 PAN-PMMA 纳米纤维的复合材料表现出比添加静电纺 PAN-PMMA 纳米纤维的复合材料更高的 Fs（13.6%）、Ey（5.3%）和 WOF（30.4%）。当添加 1.2%质量分数的后拉伸纳米纤维时，与纯树脂相比，Fs、Ey 和 WOF 分别增加了 51.6%、64.3%和 152.0%。
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