铁质纳米粉体对甲基乙烯基硅橡胶力学性能的影响

目的探讨铁质纳米粉体改性甲基乙烯基硅橡胶的力学性能变化及其在基胶中的分散状态。方法根据国家标准对前期制备出的纳米铁粉增强硅橡胶和碳包铁粉增强硅橡胶复合材料进行邵氏A硬度、拉伸强度、扯断伸长率、扯断永久变形率、撕裂强度等力学性能指标测试，使用热场发射扫描电镜（TFE．SEM）观察复合材料的表面形貌和断口形貌，了解纳米铁在硅橡胶基体的分散状态。结果复合材料试件的邵氏A硬度、拉伸强度、扯断伸长率、扯断永久变形率、撕裂强度的均值随着铁质纳米粉体添加量的增加而增加。当纳米铁在配方中的份数大于17份、碳包铁的份数大于19份时，复合材料的拉伸强度均值不再增加反而呈下降趋势；当铁质纳米粉体的在配方中超过15份时，扯断伸长率、撕裂强度的均值开始下降。铁质纳米微粒在硅橡胶的表面分散均匀，在配方比为85：15的硅橡胶，纳米铁试样的断面及配方比87：13的硅橡胶／碳包铁试件的断面，可观察到粉体的团聚体。结论纳米铁粉体和碳包铁粉体对甲基乙烯基硅橡胶力学性能的补强作用主要取决于纳米粉体的粒径、添加量以及在基胶中的团聚程度。

Effect of ferric nanopar ticles on the mechanical properties of methyl vinyl silicone rubber

Objective To explore mechanical property changes of methyl vinyl silicone rubber modified by ferric nanoparticles and its dispersed phase.Methods Mechanical properties such as Shore A hardness,tensile strength,elongation at break,tearing rate of permanent deformation and tearing strength of pre-prepared ironic nanoparticle enhanced silicone rubber and carbon-coated ferric particle reinforced silicone rubber were tested according to national standards.A thermal field emission scanning electron microscope (TFE-SEM) was used to investigate the morphology of both surface and fracture of the composite materials and to observe the dispersion of ferric nanoparticles in them.Results Mean values of Shore A hardness,tensile strength,elongation at break,tearing permanent deformation rate and tear strength of modified composites increased with the increasing amounts of ferric nanoparticles,however,when the quota of ironic nanoparticles in the composite formula were greater than 17 phr,carbon-coated ferric nanoparticles more than 19 phr,the mean values of tensile strength of two composites stopped increasing and presented the declining trend.When the quota of ferric nanoparticles in the formula exceeding 15 phr,the mean values of elongation at break and tear strength began to decrease in the formula ratio of silicone rubber/ferric nanoparticles up to 85:15,while the Shore A hardness of samples increased all the way.Ferric nanoparticles dispersed evenly on the surface of composites.Nanopowder aggregation in the fracture surface of both composites could be observed at the formula ratio of 85:15 of silicone rubber/iron nanoparticle and 87:13 of silicone rubber/carbon-coated iron specimen.Conclusion Effect of iron nanapareticles and carbon-coated ferric nanoparticles on the mechanical properties of the reinforced methyl vinyl silicone rubber depends on the nanoparticle size,additive amount and agglomeration.