牙科复合树脂中无机填料的堆积孔隙率与其粒度分布的关系

通过测定松装密度和振实密度 ,研究了牙科复合树脂中无机填料的粒度分布与其堆积孔隙率之间的关系。使用Mathematica软件和SAS/STAT软件 ,用非线性回归的方法得到了无机填料的粒度分布与其堆积密度之间关系的经验公式 ,结论为无机填料 (BG)的平均粒径为 1μm ,可以作为影响堆积优化的判据     

红外差示光谱法在复合材料界面反应研究中的应用

本文以红外差示光谱法从化学键的角度对偶联剂与几种复合树脂常用填料的相互作用以及树脂基体间的相互作用予以探讨,为复合树脂的制备中如何选择填料以获得强度高、性能好的牙科材料提供了研究方法和理论依据。     

红外差示光谱法在复合材料界面反应研究中的应用

本文以红外差示光谱法从化学键的角度对偶联剂与几种复合树脂常用填料的相互作用以及树脂基体间的相互作用予以探讨,为复合树脂的制备中如何选择填料以获得强度高、性能好的牙科材料提供了研究方法和理论依据。      

纳米复合树脂口腔修复材料的研制及性能表征

利用纳米技术和分子组装技术,将具有生物相容性的羟基磷灰石材料作为牙齿龋洞的修复充填的无机填料,与有机树脂基质有机地复合和组装,从而开发出强度高、易加工且具有良好生物相容性的复合树脂牙齿修复材料。根据我国医药行业标准YY1042—2003《牙科学聚合物基充填、修复和粘固材料》,对纳米复合树脂材料挠曲强度、压缩强度以及吸水值等性能进行了实验室阶段的表征,性能完全达到目前临床使用的进口牙科复合树脂的各项指标。     

抗菌剂用于牙科复合树脂的研究进展

龋病是常见的口腔疾病,填充修复是治疗的重要手段.复合树脂凭借色泽美观和理化性能优异等特点,广泛应用于牙科修复材料中.继发龋是临床应用中导致修复失败的主要原因之一.为了抑制继发龋、延长树脂使用寿命,研发具有长期抗菌功能的牙科复合树脂具有重要意义.目前,主要通过向复合树脂体系中添加抗菌型无机粒子或抗菌型有机单体赋予材料抗菌...     

三级硅基填料的构筑及其对牙科复合树脂性能的影响

为提高无机填料在牙科复合树脂中的堆积密度,采用八乙烯基多面体低聚倍半硅氧烷(OV-POSS)作为第三级填料,填充双模SiO_2填料(SiO_2纳米粒子SiO_2纳米团簇)型复合树脂中的空隙。用高分辨率透射电镜(HR-TEM)和动态光散射仪(DLS),研究了OV-POSS的形貌和粒径,并利用UV-vis-NIR分光光度计、万能实验机和MTT比色法,研究了三级填料的组成对复合树脂性能的影响。结果表明:OV-POSS形貌为近球形,粒径为(4.0±2.9)nm;当OV-POSS的添加量≤5wt.%时,复合树脂的性能逐渐得到改善,尤其当OV-POSS的质量分数为5%时,复合树脂的透光率和细胞活性优于商品化纳米团簇型树脂Z350 XT,且其弯曲强度(112.3 MPa±5.6 MPa)、弯曲模量(6.6 GPa±0.2 GPa)和压缩强度(217.8 MPa±5.3 MPa)达到最大值,较未添加OV-POSS的树脂分别提高了7.2%、4.8%和5.8%。但是,随着OV-POSS含量增加(≥10wt.%),OV-POSS易聚集且散射更多的光,导致复合树脂性能下降。     

牙科复合树脂中无机填料双峰混合体的堆积性能

通过测定用作牙科复合树脂中无机填料的粉体的振实密度 ,使用Mathematica和SAS/STAT软件 ,用统计学的方法得到了双组分粉体混合物的粒度分布与堆积体比容之间关系的经验公式。说明可以使用引入了粒度分布宽度作为变量的改良线性堆积模型预测双峰粉体的堆积密度。结论为双组分粉体大小粒径比相差越大 ,混合物堆积密度越高。该结论为优化牙科复合树脂的组成提供了理论依据     

无机填料的改性及其在复合材料中的应用

阐述了填料表面改性技术即偶联剂处理技术、表面活性剂处理技术、等离子体处理技术的最新研究进展 ,介绍了几种典型无机填料在复合材料中的应用现状以及填料粒径、形状和含量对填充效果的影响     

纳米技术在牙科复合树脂改良中的应用

以牙科复合树脂现存缺点为背景,对纳米技术对复合树脂的改良情况进行了研究,着重讨论了纳米材料对复合树脂的聚合收缩、抗菌性能和机械性能改良的一系列问题。研究结果表明,使用纳米技术和材料可以很好地改进复合树脂多方面的性能,同时对复合树脂的发展方向和研究前景进行了展望。     

非金属矿物超细及表面改性加工技术

1．应用与市场 在塑料、橡胶、涂料、胶粘剂等高分子复台材料领域，非金属矿物粉体填料占有很重要的地位。由于矿物粉体填料与高分子聚合物之间的相容性决定了复合材料的性能，需对无机矿物进行超细及表面改性处理．以改善其表面物理化学特性和分散度，从而达到提高制品性能和通过填充来达到降低制品成本的目的。目前市场对细度在400-2500目的非金属矿微粉的需求量较大，随着复合材料工业的发展，对各类工业矿物填料的将会继续增加。     

ZnO介晶填料的制备及其齿科复合树脂的性能

无机填料是齿科修复复合树脂的主要成分, 它对复合树脂的性能和功能至关重要。本文以三乙醇胺为软模板剂, 六水合硝酸锌为主要原料, 水热法制备平均晶粒尺寸37.5 nm ZnO晶粒构筑的微米级多孔介晶微球, 具有良好的有序性。经γ-甲基丙烯酰氧丙基三甲氧基硅烷(γ-MPS)对ZnO介晶微球改性后, 与改性的SiO₂微球混合, 添加到Bis-GMA/TEGDMA树脂体系中, 制成复合树脂。通过形貌和性能测试发现, 20wt% ZnO介晶填充的复合树脂中填料分散均匀、力学和耐磨损性能优异, 其中树脂弯曲强度133 MPa、弯曲模量9.8 GPa; 磨损3000次后, 树脂体积损耗为1.02 mm ³, 磨损量比商业ZnO微球和单纯SiO₂填充的复合树脂分别降低了88.7%和90.8%。而且, 含氧化锌的复合树脂对口腔中变异链球菌的抗菌率达到99.9%。     

Al2O3/TiO2复配改性环氧树脂的绝缘特性

为了满足高压直流输电体系对绝缘子性能的特殊要求,使用三氧化二铝(Al₂O₃)和二氧化钛(TiO₂)复配掺杂的方法改性环氧树脂基底,对复合物表面结构以及绝缘特性进行了分析。绝缘性能测试结果表明,相比于Al₂O₃或者TiO₂单独掺杂,共掺杂可以更显著降低复合物表面电阻率并且增加电气强度。将2种纳米材料的质量调到合适比例时,纳米粉体/树脂基底界面上会形成一定的导电通道,载流子可以沿着通道被传导出去,从而改善表面电阻率。而适当量Al₂O₃的引入可以进一步改善材料的电气强度。优化后复合物的表面电阻率为8.62×10¹³Ω,电气强度可达到29.01 kV/mm,共掺杂的协同效应对于树脂绝缘性能的提升十分有意义。     

应用宽频介电谱研究氢氧化铝/环氧树脂复合材料的α和β松弛行为

聚合物的松弛行为直接影响其使用范围。本文应用宽频介电谱技术研究了中心粒径为2 μm的氢氧化铝（ATH）填料对环氧树脂复合材料α和β松弛过程的影响。宽频介电谱的测试频率范围为0.1 Hz~2 MHz,温度范围为-100~100℃。ATH填料与环氧树脂的质量比为0%、20%、40%、60%、80%和100%。结果表明：填料对复合材料的α松弛过程影响较小,Vogel温度随填料的增加先减小后增大;β松弛的表观活化能随填料的增加先增大后减小,当ATH填料质量比为40%时,β松弛的表观活化能达到最大值。     

高导热云母胶制备工艺研究

采用无机纳米氮化铝粉体填充改性环氧树脂,获得所需的高导热云母胶。针对氮化铝粉体的表面改性、粉体掺杂方式对云母胶导热系数的影响进行了系统分析。经导热系数测试,确定了粉体的表面改性工艺,得到了最佳的粉体分散工艺。     

Characterization of adsorbed silane on fillers used in dental composite restoratives and its effect on composite properties

The purpose was to study the effect of silane treatment of fillers on viscosity, flexural strength, and hydrolytic degradation of experimental dental composite resins fabricated with these fillers. The fillers consisted of a mixture of barium glass and amorphous silica. The resin was mainly based on ethoxylated bisphenol A dimethacrylate and polycarbonate dimethacrylate. The adsorption of silane on the filler surface was characterized by FTIR. There was significant correlation between the adsorbed silane on filler surface and the silane concentration in silane/methanol solution used for filler treatment. The silane concentration varied from 0.75 to 14% by weight. An increase in silane concentration led to a decrease in viscosities of the corresponding composite resins. The flexural strengths of composites with silanated fillers were greater than that of composites with unsilanated fillers: however, no significant difference was found between the flexural strengths of various silanated groups. The resistance to hydrolytic degradation of different composites increased when the fillers were treated with silane and was the highest at 1.1% silane.     

重质碳酸钙/硅灰石复合填料的填充性能与填充增强原理研究

研究了简单混合、研磨复合以及表面改性后的重质碳酸钙 /硅灰石复合活性填料填充PVC材料的力学性能与填充增强原理。结果表明 ,与单一填料及简单混合后的重质碳酸钙 /硅灰石填料相比 ,研磨复合及表面改性后的重质碳酸钙 /硅灰石复合活性填料可以显著增强PVC材料的力学性能。这种复合活性填料的主要填充增强原理是复合活化增强以及颗粒粒度和形状配合增强 ,即两种不同无机非金属矿物粉体混合后的化学组成和结构复杂化、复合加工后的表面活性化、表面改性后与高聚物基料的相容化以及在填充材料中的取向和堆砌效应的优化     

Evaluation of reinforced strength and remineralized potential of resins with nanocrystallites and silica modified filler surfaces

Surface-modified dicalcium phosphate anhydrous particles that were treated with an ion-rich solution and a silane-coupling agent were evaluated as fillers for resin composites. The physiochemical properties of these composites were characterized. The properties of the specimens as reinforcements, which were modified using various surface conditions and 30% and 50% filler to composite mass ratios (30% and 50%) were measured before and after they were immersed in water for 24 h. All groups were of the same strength and showed no significant changes after immersion. However, the groups showed a significant increase in the modulus after 24 h of immersion. The filler surfaces with nanocrystallites had the highest modulus, whereas the fillers treated with silanization had the lowest ion concentration in the solution and highest remineralization ability after immersion. The strength and brittleness were increased by the modified fillers with nanocrystallites on the surfaces and by the increased amount of fillers in the resin composites. Filler surfaces that were modified with silica hindered interfacial interactions and consequently had better flexibility and less brittleness during the light-curing process. Surface modifications of reinforced particles using nanocrystallites and silica films have superior potential applications in restorative medicine.     

Nonlinear fillers in electrical insulating materials

Nonlinear composite dielectric materials can be formed through the inclusion of appropriate fillers in polymers. Depending on the type of filler used, the composite material can then possess either an electrical field-dependent conductivity (FDC) or an electrical field-dependent permittivity (FDP). These nonlinear properties can then be used for the purposes of electrical stress relief in insulation systems with divergent electric fields, reducing the intensity of highly stressed regions. FDC polymer composites are formed through the inclusion of narrow-band gap semiconductive fillers in a polymer matrix and can be used for electrical stress relief in both AC and DC applications. FDP materials on the other hand use ferroelectric fillers in polymers; however, the stress-relieving properties of these materials are only realisable under AC fields. The paper reports on the electrical characterisation of both of these stress-relieving materials, with the criteria required for them to function. The materials that have been studied in these investigations take the form of zinc oxide in epoxy resin and barium titanate in an acrylic resin, respectively. Improvements in thermal conductivity are also reported as a consequence of the introduction of these fillers     

Starch granules spot-coated with aluminum silicate particles and their use as fillers for papermaking

Mineral fillers are among the most important raw materials of paper. In papermaking, a filler is typically mixed as such with the fibrous stock prior to the forming section where it, together with the fibers and fines, forms a paper web with heterogeneous three-dimensional composite structure. The filler is eventually located both in the paper pores and between adjacent fibers. When light interacts with a multitude of solid-air interfaces occurring in such a structure, complicated light scattering effects take place. These effects are essential for appearance development, viz. brightness and opacity. Fillers contribute to these effects by increasing the number of such interfaces. Many fillers also cost significantly less than fibers. Therefore, it is advantageous to introduce as much filler as possible. It is also well known, however, that filler prevents formation of hydrogen bonding and is hence detrimental for strength development. In addition, the legislation of European Union favors increasing recovery of paper and packaging products, e.g., for energy production. However, as a side product of paper waste incineration, significant amounts of ash is formed. Hence it would be advantageous to replace inorganic fillers with combustible organic materials. We have fabricated a novel aluminum silicate spot-coated starch-based filler. The results indicate that when silicate is introduced in paper on the surface of starch granules benefits in light scattering and strength development can be achieved.     

Re‐Use of Marble Stone Powders in Producing Unsaturated Polyester Composites

The main goal of this study is to evaluate the potential of waste stone powders as filler in composite materials with a matrix of unsaturated polyester. These wastes are generated in the form of stone fragments and stone‐cutting sludge. Ground marble wastes are thoroughly characterized with the aim to use them as fillers: Mineralogical and chemical composition, particle size distribution, and morphology of these waste stone powders are investigated. Unsaturated polyester resin composites with the different stone powder fillers are prepared. The influence of powder type on the composites’ mechanical properties (tensile, bending, impact, and hardness characteristics), water resistance, thermal stability as well as surface fracture morphology of composites are studied. The moduli of the composites increase by 100%, the hardness of the composites may be improved by 80% upon loading with the “waste” filler, leading to an economical material and helping to reduce waste.