Influence of silane content and filler distribution on chemical-mechanical properties of resin composites

This study investigated the influence of silane concentration and filler size distribution on the chemical-mechanical properties of experimental composites. Experimental composites with silane contents of 0%, 1% and 3% (in relation to filler mass) and composites with mixtures of barium glass particles (median size = 0.4, 1 and 2 μm) and nanometric silica were prepared for silane and filler analyses, respectively. The degree of conversion (DC) was analyzed by FTIR. Biaxial flexural strength (BFS) was tested after 24-h or 90-d storage in water, and fracture toughness, after 24 h. The data were subjected to ANOVA and Tukey’s test (p = 0.05). The DC was not significantly affected by the silane content or filler distribution. The 0% silane group had the lowest immediate BFS, and the 90-d storage time reduced the strength of the 0% and 3% groups. BFS was not affected by filler distribution, and aging decreased the BFS of all the groups. Silanization increased the fracture toughness of both the 1% and 3% groups, similarly. Significantly higher fracture toughness was observed for mixtures with 2 μm glass particles. Based on the results, 3% silane content boosted the initial strength, but was more prone to degradation after water storage. Variations in the filler distribution did not affect BFS, but fracture toughness was significantly improved by increasing the filler size.

本研究探讨了硅烷（silane）浓度与填料粒度分布对实验用复合材料化学-力学性能的影响。本研究分别制备了两类实验用复合材料：一类硅烷含量为0%、1%及3%（相对于填料质量），用于硅烷相关分析；另一类由钡玻璃颗粒（中位粒径分别为0.4、1及2 μm）与纳米二氧化硅混合制得，用于填料相关分析。采用傅里叶变换红外光谱（Fourier Transform Infrared Spectroscopy, FTIR）对转化率（Degree of Conversion, DC）进行分析；双轴抗弯强度（BFS）分别在水基储存24小时及90天后开展测试，断裂韧性则在水基储存24小时后测试。所有实验数据均采用方差分析（ANOVA）与图基（Tukey）多重比较检验进行统计分析，显著性水平设定为p=0.05。结果显示，DC未受硅烷含量与填料粒度分布的显著影响。未添加硅烷的组别其即时双轴抗弯强度最低；水基储存90天会降低未添加硅烷组与3%硅烷组试样的强度。双轴抗弯强度不受填料粒度分布的影响，而老化处理会降低所有组别试样的双轴抗弯强度。硅烷化处理同样可提升1%与3%硅烷组试样的断裂韧性；当填料为中位粒径2 μm的钡玻璃颗粒时，复合试样的断裂韧性显著更高。基于上述实验结果，3%的硅烷含量可提升试样的初始强度，但经水基储存后更易发生性能降解。填料粒度分布的变化未对双轴抗弯强度产生影响，但增大填料粒径可显著提升试样的断裂韧性。