氧化锆的用量对纳米氧化锆/PMMA复合材料挠曲性能的影响

目的：研究氧化锆的添加量对纳米ZrO2/PMMA复合材料挠曲强度的影响。方法：采用球磨仪混合基托树脂（聚甲基丙烯酸甲酯,PMMA）Ⅱ型粉剂和硅烷偶联剂Z-6030修饰过的纳米氧化锆粉体,合成纳米ZrO2/PMMA复合材料,按照氧化锆的用量从0%到7%,制作8组标准试件,测试材料的挠曲强度。结果：氧化锆添加量为3%组的挠曲强度最大,与实验组中的4%组无统计学上的差异,与空白组及实验组中的其他组均有统计学上的差异（P〈0.05）,SEM观察断裂面为韧性断裂,其中3%和4%两组断裂面比较的粗糙。结论：经过硅烷修饰的纳米ZrO2颗粒,在其添加量为3.0%时,可以显著地提高纳米ZrO2/PMMA复合材料的挠曲强度。     

不同分散方法对纳米ZrO2/PMMA复合材料挠曲强度的影响

目的:研究不同分散方法对氧化锆(zrO2)纳米填料/聚甲基丙烯酸甲酯(PMMA)复合材料试件挠曲强度的影响.方法:在丙酮溶液中用硅烷偶联剂Z-6030对纳米ZrO2颗粒进行表面修饰,将经过表面修饰后的纳米ZrO2颗粒按照3%的添加量加入到义齿基托树脂Ⅱ型粉剂中,然后分别采用手工、球磨和超声湿混3种方法予以分散混合,并以不添加纳米ZrO2颗粒的PMMA作为空白对照组,再与Ⅱ型液剂反应后制成4组标准试件,最后进行三点弯曲测试.实验数据采用SAS6.12软件包进行单因素方差分析,均数间进行两两比较(Newman-Keuls检验).结果:复合材料的挠曲强度以球磨组最高,达73.64 MPa,手工混合组最低,为62.86 MPa.球磨、超声2组的挠曲强度显著高于手工组和空白对照组(P<0.05).球磨和超声2组之间无显著差异(P>0.05).结论:以球磨、超声2种方法混合纳米ZrO2颗粒和PMMAⅡ型粉剂,可得到较好的分散效果,从而提高复合树脂的挠曲强度.     

纳米氧化锆对PMMA挠曲强度和表面硬度的影响

目的:研究纳米ZrO2的添加量对聚甲基丙烯酸甲酯(PMMA)基托树脂机械性能的影响。方法:使用质量分数为1.5%的硅烷偶联剂Z-6030对纳米ZrO2颗粒进行表面处理及FTIR表征分析,未经处理者为对照组。将经过表面处理的纳米ZrO2颗粒按照质量比0.5%、1%、1.5%、2%、2.5%、3%和3.5%的添加量与PMMA混合,合成纳米ZrO2/PMMA复合材料,共7组。制作标准试件,进行表面硬度测试和三点弯曲测试,从每组中随机选取1个试件进行扫描电镜观察。采用SAS 6.12软件包对数据进行ANOVA单因素方差分析。结果:红外光谱图显示,经过表面处理的纳米ZrO2颗粒表面有硅烷偶联剂吸附。纳米ZrO2添加量为1.5%和2%组复合材料的表面硬度最佳(P<0.05)。1.5%组复合材料的挠曲强度最高(P<0.05),SEM观察断裂面为韧性断裂。结论:使用硅烷偶联剂能提高纳米ZrO2与PMMA的结合强度,经过表面处理的纳米ZrO2,能提高复合材料的机械性能,但加入量会影响纳米ZrO2的增强作用。纳米ZrO2以1.5%和2%的添加比例对基托材料的表面硬度增强效果最佳,以1.5%的添加比例对PMMA挠曲强度的增强效果最...     

纳米(PMMA/蒙托土)义齿基托复合材料力学性能的研究

目的:研究蒙托土对聚甲基丙烯酸甲酯(PMMA)义齿基托力学性能的改善。方法:将有机蒙托土按2.64%、3.89%、5.56%、6.92%的质量比加入聚甲基丙烯酸甲酯(PMMA)粉中,制成不同浓度的纳米(PMMA/蒙托土)义齿基托复合材料,对各组的挠曲弹性模量、挠曲强度进行检测,并对结果进行统计学分析。结果:添加蒙托土为2.64%、3.89%(质量比)的纳米(PMMA/蒙托土)义齿基托与普通PMMA义齿基托相比,挠曲弹性模量有所提高(P<0.05),挠曲强度没有显著性差异(P>0.05)。添加蒙托土为5.56%(质量比)的纳米(PMMA/蒙托土)义齿基托与普通PMMA义齿基托相比,挠曲弹性模量、挠曲强度均没有显著性差异(P>0.05)。添加蒙托土为6.92%(质量比)的纳米(PMMA/蒙托土)义齿基托与普通PMMA义齿基托相比,挠曲弹性模量没有显著性差异(P>0.05),挠曲强度下降(P<0.05)。结论:在聚甲基丙烯酸甲酯义齿基托中添加一定质量比有机蒙托土在不影响其挠曲强度的条件下可以改善其挠曲弹性模量。     

纳米义齿基托树脂的制备及挠曲性能的研究

目的在聚甲基丙烯酸甲酯粉（PMMA）中添加有机改性的蒙脱土制备纳米义齿基托树脂,以增强义齿基托树脂的挠曲性能。方法将蒙脱土经十六烷基三甲基溴化铵改性,形成有机化改性的蒙脱土,将其加入牙托粉中形成混和粉,混和粉与热凝牙托水调和后经加热固化形成纳米义齿基托树脂。用X射-线衍射（XRD）和透射电子显微镜（TEM）表征了固化后材料的结构,用三点挠曲试验测量固化后材料的挠曲强度和挠曲弹性模量。用一维方差分析法评价有机化蒙脱土的量对挠曲强度的挠曲弹性模量的影响。结果 XRD、TEM证实当蒙脱土在混合粉中的量为3%和5%时,蒙脱土在PMMA基质中形成部份剥离和插层结构;当蒙脱土在混合粉中的量为3%时,挠曲强度达最大,进一步增加蒙脱土的量,材料的挠曲强度降低。当混和粉中有机蒙脱土的量在1%~10%时,挠曲弹性模量随有机蒙脱土的量增加而增加。一维方差分析表明当混和粉中有机蒙脱土的量为3%时,实验组的挠曲强度与挠曲弹性模量均存在显著性差异（n=5,P〈0.05）。结论牙托粉中蒙脱土的量对义齿基托树脂的挠曲性能有显著性影响。     

硅烷偶联剂用量对硼酸铝晶须增强PMMA挠曲强度影响的研究

目的研究硅烷偶联剂用量对硼酸铝晶须增强聚甲基丙烯酸甲酯(PMMA)挠曲强度的影响。方法使用质量分数为1.0%、2.0%、3.0%、4.0%的硅烷偶联剂Z-6030对硼酸铝晶须进行表面处理,未经处理的为对照组。把经过处理的硼酸铝晶须以10%添加量与PMMA混合,合成硼酸铝晶须/PMMA复合材料,制成标准试件5组。最后进行3点弯曲测试并且每组随机选出1个试件进行断面扫描电镜观察。结果5组的抗弯强度分别是67.59±5.35、72.96±4.20、75.52±4.89、71.26±5.94、(68.25±3.43)MPa。当硅烷偶联剂的用量为硼酸铝晶须质量的2.0%时,挠曲强度达到最大。利用SAS统计软件对5组的结果进行均数间的两两比较(Newman-Keuls检验)分析可知,硼酸铝晶须/PMMA复合材料各组间挠曲强度的差异无统计学意义(P>0.05)。断面的电镜扫描可见以2.0%硅烷偶联剂修饰硼酸铝晶须时,晶须与树脂间的结合牢固,且其在基质中分散也良好。结论使用硅烷偶联剂能够提高硼酸铝晶须与PMMA树脂间的结合强度,改善其在树脂基质中的分散性,提高复合材料的物理机械性能,但过多或过少均会影响复合材料的强度。针对本实验所使用的晶须、偶联剂以及偶联化方法,硼酸铝晶须用于增强PMMA时最佳的硅烷偶联剂使用量为2.0%。     

不同偶联剂用量对纳米SiO2增强聚甲基丙烯酸甲酯力学性能的影响

目的：研究硅烷偶联剂和钛酸酯偶联剂用量对纳米SiO2增强聚甲基丙烯酸甲酯（PMMA）力学性能的影响。方法分别使用质量分数为1%、2%、3%、4%、5%的硅烷偶联剂和钛酸酯偶联剂对纳米SiO2进行表面改性,将处理后的纳米SiO2按3%添加量与PMMA混合后制作标准模件,未经处理的为对照组,进行三点弯曲实验、硬度及摩擦磨耗测试。结果硅烷偶联剂和钛酸酯偶联剂的最佳用量为2%和3%。结论在一定质量分数范围内2种偶联剂改性的纳米SiO2均能提高树脂基托的机械强度,针对本实验所用的偶联剂及方法,硅烷偶联剂的最佳用量为2%;钛酸酯偶联剂的最佳用量为3%。     

硅烷偶联剂用量对硼酸铝晶须增强树脂挠曲强度的影响

目的:评价硅烷偶联剂用量对硼酸铝晶须增强树脂挠曲强度的影响。方法:使用0%、1%、2%、3%、4%质量分数的Z-6030对硼酸铝晶须进行表面处理;将处理过的晶须和树脂基质按一定的配方合成5组热固化型复合树脂,每组6个试件,在120℃的烘箱内固化1 h后,按ISO-4049标准进行三点弯曲测试。每组随机选1个试件,进行断面扫描电镜观察。采用SAS 9.2软件包对结果进行均数间两两比较。结果:硅烷偶联剂用量为2%质量分数时,增强树脂的挠曲强度（117.93±11.9）MPa最高,与其余4组差异显著。结论:硅烷偶联剂的用量对晶须的增强效果有显著影响,过多或过少均会降低复合树脂的挠曲强度。     

不同出盒温度对义齿塑料基托适合性的影响

不同出盒温度对义齿塑料基托适合性的影响方金素张春宝王宝成（第四军医大学口腔医学院修复科７１００３２）用于制作义齿塑料基托的聚甲基丙烯酸甲酯在热处理聚合过程中，由于其液剂和粉剂的体积差别，会产生聚合收缩，引起塑料基托的形变，因而影响塑料基托与颌骨模型的...     

PMMA纳米复合材料的研究进展

聚甲基丙烯酸甲酯(PMMA)义齿基托材料是目前使用最广泛的义齿基托材料,但PMMA的性能仍然存在诸多不足之处,近年来用纳米无机填料增强PMMA性能成为PMMA改性研究领域的新方向。本文简介PMMA纳米复合材料的研究进展。     

超强聚乙烯纤维增强树脂基托性能的实验研究

目的：评价在义齿基托树脂中加入超强聚乙烯纤维后的挠曲性能。方法：在义齿基托树脂中加入不同质量分数的超强聚乙烯纤维，测试其挠曲强度，与未加入纤维的基托树脂对比；同时在扫描电镜下观察其断面情况。结果：加入超强聚乙烯纤维的基托树脂的挠曲强度要高于对照组，在3．5wt％时达最大值，电镜结果显示纤维在基质中均匀分布。结论：超强聚乙烯纤维能提高义齿基托的挠曲强度。     

Effect of Mica Reinforcement on the Flexural Strength and Microhardness of Polymethyl Methacrylate Denture Resin

Purpose : Conventional denture base polymethyl methacrylate (PMMA) is low in strength, soft, and brittle on impact. Improvements in the mechanical properties of denture base materials have been sought by adding different reinforcing phases to the PMMA matrix. The purpose of this work was to study the effects of mica reinforcement on the mechanical properties, flexural strength, and microhardness of PMMA denture base resin. Materials and Methods : Wet ground muscovite mica and Lucitone 199 original shade denture base resin were used. Two micas were tested: W200 and P66 with average particle sizes (d50) of 131 μm and 30 μm, respectively. The mica was silane treated in a solution of 3‐methacryloxypropyl trimethoxysilane, ethanol, and water, and then dried. The specimens were fabricated using the denture base resin manufacturer's instructions with a powder : liquid ratio of 21 g/10 ml and a mixing time of 30 seconds. Five treatment groups were produced with differing amounts of mica added to the PMMA denture base resin: (A) control group with 0 vol% mica, (B) 10 vol% W200 mica, (C) 20 vol% W200 mica, (D) 10 vol% P66 mica, (E) 20 vol% P66 mica. The mica replaced equal volumes of the PMMA powder component to minimize changes in viscosity. The three‐point bending flexural strength specimens were 70 × 11 × 3 mm³. Seven specimens were prepared for each treatment group. The hardness specimens were prepared from the ends of the three‐point bend specimens after they were broken (N = 7). After deflasking, the specimens were polished with 600 grit silicon carbide paper to achieve smooth surfaces. A standard three‐point bending jig with a span length of 50 mm was attached to an Instron universal testing machine. The specimens were placed on the jig, and loading was carried out using a 1 mm/min crosshead speed until failure. Microhardness was measured using a Clark microhardness tester with a Knoop indenter. The load was set to 200 g and the dwell time to 15 seconds. ANOVA and Tukey tests were used for statistical analyses (Alpha = 0.05). Results : The flexural strength of the control group was between 77% and 94% higher than all the mica‐containing groups (p≤ 0.05). No significant differences were found within the four mica groups. Microhardnesses of the 20% mica groups (both fine and coarse) were 33% and 26% higher than the control (p≤ 0.05). The 10% mica groups had higher hardness than the control group, but the increase was not statistically significant (p > 0.05). Conclusion : Mica additions to denture PMMA reduced flexural strength; however, with the specimens containing highest mica concentrations (20%), microhardness significantly increased.     

Reinforcement of denture base resin with short vegetable fiber

Objectives

Short ramie fibers were selected to investigate the effect of fiber length and volume fraction on the flexural properties of ramie fiber reinforced denture base PMMA. With the aid of measured interfacial shear strength and theoretical prediction values, experimental results were well interpreted.

Methods

Interfacial properties between denture base PMMA and ramie fibers were evaluated by single fiber pull-out test. Then, chopped ramie fibers were pre-stirred with PMMA powder by a mechanical blender and then mixed with MMA liquid to fabricate composites. Two crucial influencing factors, fiber volume fraction and fiber length, were studied to clarify their effects on flexural properties of composites.

Results

With 1.5 mm fibers addition, flexural modulus of denture base PMMA rose from 2.50 to 3.46 GPa with 10 vol.% fibers, while flexural strength declined steadily with increment of fiber content. If fiber length was 3.0 mm, the modulus showed a growth to 3.5 GPa at 4 vol.% fiber content followed by a drop to 3.00 GPa at 10 vol.%, whereas fluctuation in strength was experienced. Experimental results were discussed by comparison with two theoretical models.

Significance

Short ramie fiber reinforced denture base PMMA had higher flexural modulus than neat resin, while strength was lowered due to the weak interfacial adhesion. The potential of vegetable fibers as reinforcing agents for denture base should be further investigated by strengthening the interface between cellulose and denture base PMMA.     

Flexural strength and moduli of hypoallergenic denture base materials

STATEMENT OF PROBLEM: Hypoallergenic denture base materials show no residual methyl methacrylate (MMA) or significantly lower residual MMA monomer content compared to polymethyl methacrylate-based (PMMA) heat-polymerizing acrylic resin. There is insufficient knowledge of the mechanical properties of hypoallergenic denture base materials to warrant their use in place of PMMA-based acrylic resins for patients with allergic reaction to MMA. PURPOSE: This in vitro study compared flexural strength and flexural modulus of 4 hypoallergenic denture base materials with flexural strength/modulus of a PMMA heat-polymerizing acrylic resin. MATERIAL AND METHODS: The following denture base resins were examined: Sinomer (heat-polymerized, modified methacrylate), Polyan (thermoplastic, modified methacrylate), Promysan (thermoplastic, enterephthalate-based), Microbase (microwave-polymerized, polyurethane-based), and Paladon 65 (heat-polymerized, methacrylate, control group). Specimens of each material were tested for flexural strength and flexural modulus (MPa, n = 5) according to ISO 1567:1999. The data were analyzed with 1-way analysis of variance and the Bonferroni-Dunn multiple comparisons post hoc analysis for each test variable (alpha=.05). RESULTS: Flexural strength of Microbase (67.2 +/- 5.3 MPa) was significantly lower than Paladon 65 (78.6 +/- 5.5 MPa, P <.0001). Flexural strength of Polyan (79.7 +/- 4.2 MPa, P =.599), Promysan (83.5 +/- 3.8 MPa, P =.412), and Sinomer (72.3 +/- 2.1 MPa, P =.015) did not differ significantly from the control group. Significantly lower flexural modulus was obtained from Sinomer (1720 +/- 30 MPa, P =.0007) compared to the PMMA control group (2050 +/- 40 MPa), whereas the flexural modulus of Promysan (2350 +/- 170 MPa, P =.0005) was significantly higher than the PMMA material. Microbase (2100 +/- 210 MPa, P =.373) and Polyan (2070 +/- 60 MPa, P =.577) exhibited flexural modulus similar to the PMMA material. The tested denture base materials fulfilled the requirements regarding flexural strength (>65 MPa). With the exception of Sinomer, the tested denture base resins passed the requirements of ISO 1567 regarding flexural modulus (>2000 MPa). CONCLUSION: Flexural modulus of Promysan was significantly higher than the PMMA material. Microbase and Sinomer exhibited significantly lower flexural strength and flexural modulus, respectively, than PMMA. The other groups did not differ significantly from the control group.     

改性纳米氧化铈对义齿树脂基托机械性能的影响

目的:研究经硬脂酸改性后的纳米CeO₂对义齿树脂基托机械性能的影响。方法:将改性纳米颗粒按照质量比分别为1%、2%、3%、4%和5%的添加量添加到义齿基托材料(PMMA)的单体中,制成不同浓度的纳米齿复合材料,制成标准试件。对每组试件冲击强度,弯曲强度等指标进行检测,并与未添加纳米颗粒组比较,将最终数据进行统计分析。结果:经硬脂酸改性后的纳米氧化铈能够提高树脂基托的机械性能,所测试指标都呈现先增大后减小的趋势。其中添加比例为3%时纳米复合材料的综合性能达到最佳状态,其冲击强度、弯曲强度和弯曲模量分别为(4.186±0.149) J/cm²、(88.865±2.345) MPa和(1.539±0.096) GPa(P<0.05)。结论:在义齿基托材料单体中加入不同浓度的纳米氧化铈颗粒可以提高传统义齿基托的冲击强度,弯曲强度等机械性能,从而可以获得品质优良的纳米义齿复合材料。