Département de Chimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, QC, H3C 3J7, Canada.
Département de Chimie, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, QC, H3C 3J7, Canada.
Dent Mater. 2017 Mar;33(3):288-293. doi: 10.1016/j.dental.2016.12.006. Epub 2017 Jan 14.
The inorganic filler particles in dental resin composites serve to improve their mechanical properties and reduce polymerization shrinkage during their use. Efforts have been made in academia and industry to increase the filler particle content, but, few studies examine the theoretical basis for the maximum particle loading.
This work evaluates the packing of spherical particles in a close-packed state for highly loaded composites.
Calculations show that for low dispersity particles, the maximum amount of particles is 74.05vol%, regardless of the particle size. This can be further improved by using a mix of large and small particles or by the use of non-spherical particles. For representative spherical particles with a diameter of 1000nm, two types of secondary particles with respective sizes of 414nm (d) and 225nm (d) are selected. The results show that after embedding secondary particles I & II into primary spherical particles, the packing factor is increased to 81.19% for the close-packed structures, which shows an improvement of 9.64%, compared to the 74.05% obtained only with primary spherical particles. This packing factor is also higher than either structure with the embedded secondary particles I or II.
Examples of these mixtures with different spherical particle sizes are shown as a theoretical estimation, serving as a guideline for the design and formulation of new dental resin composites with better properties and improved performance.
牙科树脂复合材料中的无机填料颗粒可提高其机械性能并降低使用过程中的聚合收缩。学术界和工业界都在努力提高填料颗粒的含量，但很少有研究探讨最大颗粒负载的理论基础。
本工作评估了高填充复合材料中球形颗粒紧密堆积的填充情况。
计算表明，对于低分散性颗粒，无论颗粒大小如何，最大颗粒含量均为 74.05vol%。通过使用大小混合的颗粒或使用非球形颗粒可以进一步提高。对于直径为 1000nm 的代表性球形颗粒，选择了两种分别具有 414nm(d)和 225nm(d)尺寸的二级颗粒。结果表明，将二级颗粒 I 和 II 嵌入初级球形颗粒后，紧密堆积结构的堆积因子增加到 81.19%，与仅用初级球形颗粒获得的 74.05%相比，提高了 9.64%。该堆积因子也高于嵌入二级颗粒 I 或 II 的任何一种结构。
展示了这些具有不同球形颗粒尺寸的混合物的示例，作为设计和配方具有更好性能和改进性能的新型牙科树脂复合材料的理论估计。
