Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece.
Dent Mater. 2011 Aug;27(8):825-35. doi: 10.1016/j.dental.2011.04.008. Epub 2011 May 17.
The aim of this work was the synthesis of light-cured resin nanocomposites using nanosilica particles with different particle size and the study of some physical-mechanical properties of the composites.
Various types of silica nanoparticles (Aerosil) with average particle size of 40, 20, 16, 14, and 7 nm, used as filler were silanized with the silane 3-methacryloxypropyl-trimethoxysilane (MPS). The total amount of silane used was kept constant at 10 wt% relative to the filler weight to ensure the complete silanization of nanoparticles. The silanizated silica nanoparticles were identified by FT-IR spectroscopy and thermogravimetric analysis (TGA). Then the silanized nanoparticles (55 wt%) were mixed with a photoactivated Bis-GMA/TEGDMA (50/50 wt/wt) matrix. Degree of conversion of composites was determined by FT-IR analysis. The static flexural strength and flexural modulus were measured using a three-point bending set up. The dynamic thermomechanical properties were determined by dynamic mechanical analyzer (DMA). Sorption, solubility and volumetric change were determined after storage of composites in water or ethanol/water solution 75 vol% for 30 days. The TGA for composites was performed in nitrogen atmosphere from 30 to 700 °C.
As the average silica particle size decreases, the percentage amount of MPS attached on the silica surface increases. However, the number of MPS molecules attached on the silica surface area of 1 nm(2) is independent of filler particle size. As the average filler particles size decreases a progressive increase in the degree of conversion of composites and an increase in the amount of sorbed water is observed.
The prepared composites containing different amount of silica filler, with different particle size, but with the same amount of silanized silica and organic matrix showed similar flexural strength and flexural modulus, except composite with the lowest filler particle size, which showed lower flexural modulus.
本工作的目的是使用不同粒径的纳米二氧化硅颗粒合成光固化树脂纳米复合材料，并研究复合材料的一些物理力学性能。
使用平均粒径为 40、20、16、14 和 7nm 的各种类型的纳米二氧化硅（Aerosil）作为填料，用硅烷 3-甲基丙烯酰氧基丙基三甲氧基硅烷（MPS）进行硅烷化。所用硅烷的总量保持相对填料重量的 10wt%不变，以确保纳米颗粒的完全硅烷化。通过傅里叶变换红外光谱（FT-IR）和热重分析（TGA）对硅烷化二氧化硅纳米粒子进行了鉴定。然后将硅烷化纳米粒子（55wt%）与光活化双酚 A 二缩水甘油醚/三乙二醇二甲基丙烯酸酯（50/50wt/wt）基质混合。通过 FT-IR 分析测定复合材料的转化率。使用三点弯曲装置测定复合材料的静态弯曲强度和弯曲模量。通过动态力学分析仪（DMA）测定动态热机械性能。将复合材料在水或 75vol%乙醇/水溶液中储存 30 天后，测定其溶胀、溶解度和体积变化。在氮气气氛下，从 30 至 700°C 对复合材料进行 TGA。
随着二氧化硅平均粒径的减小，附着在二氧化硅表面的 MPS 的百分比增加。然而，附着在 1nm(2)表面积上的 MPS 分子的数量与填料粒径无关。随着平均填料粒径的减小，复合材料的转化率逐渐增加，吸水量也增加。
用不同粒径的不同量的二氧化硅填料制备的复合材料，用相同量的硅烷化二氧化硅和有机基质，但具有相同的有机基质，显示出相似的弯曲强度和弯曲模量，除了含有最低粒径填料的复合材料外，其弯曲模量较低。
