利用AFM研究炭黑的微观分散

Using AFM to Study the Microscopic Dispersion of Carbon Blacks

炭黑在橡胶中的分散程度对其补强性能的发挥至关重要,工业生产中用光学显微镜获得的胶料图像仅能判别炭黑粉团的聚集程度,表征混炼工艺是否合格。探究不同炭黑在橡胶中的微观分散程度,有助于从纳米尺度搞清楚炭黑分散程度对炭黑补强性能的贡献。使用原子力显微镜(AFM)获取硫化胶片截面的微观相图,表征出炭黑在橡胶中的分散程度,从分散程度角度解释了不同粒径和结构炭黑的补强性和耐磨性的差异。选取最具代表性的五种炭黑为原料,定量表征炭黑聚集体在天然橡胶中的分散程度,统计评价分析炭黑在橡胶中的聚集体尺寸分布和间距分布。结果发现:(1)炭黑原生粒径越小其炭黑微观分散程度越好;(2)N115粒径最小,在胶料中分布最均匀导致其补强性能最佳,但是粒径太小混炼困难;(3)N300系列炭黑在橡胶中,结构程度对炭黑微观分散程度的影响较小,但随着结构的增高,其补强性能更好。

The degree of dispersion of carbon black in rubber is crucial for its reinforcing performance.The image of the rubber obtained by optical microscopy in industrial production can only judge the degree of aggregation of carbon black powder cluster and characterize whether the mixing process is qualified.The micro dispersion of different carbon black in rubber is studied,and the contribution of carbon black dispersion to carbon black reinforcement is understood from the nano scale.The microscopic phase diagram of the cross section of the vulcanized film is obtained by atomic force microscopy(AFM),and the degree of dispersion of carbon black in the rubber is characterized.The difference of the reinforcing and wear resistance of different particle sizes and structural carbon blacks is explained from the perspective of dispersion degree,and the degree of dispersion of the carbon black aggregates in the rubbe is statistically evaluated to analyze the aggregate size distribution and the pitch distribution of the carbon black in the rubber by selecting the five most representative carbon blacks as raw materials.It is found that:(1)the smaller the primary particle diameter of carbon black,the better the degree of microscopic dispersion of carbon black;(2)N115 has the smallest particle size and the most uniform distribution in the rubber compound,so it has the best reinforcement performance;(3)The results of N300 series carbon black in rubber shows that the structural degree has little effect on the microscopic dispersion,but the reinforcing performance is better with the increase of the structure.