基于SPM针尖作用力定量探寻炭黑表面活性点研究

In recent years, due to the development of green tires and the promulgation of EU tyre-labeling laws, carbon blacks, the oldest carbon materials, make progress rapidly. With the emergence of plenty of new species, carbon blacks still occupies the dominant position in reinforcing fillers. However, the reinforcing mechanism of carbon blacks, especially the theory of surface activity, is still ambiguous. In this study, given the relationship between surface oxygen groups and activity of carbon blacks as a breakthrough point, we put forward the method, based on SPM tip chemistry and its force curve, to characterize the active points of carbon blacks. By increasing the acid oxygen groups in sequence, and controlling the distance between the probe tip and the surface of carbon black aggregates, we can record the adsorption or repulsion force between atoms with the force curve. At last, we use the turnning point data from the force curve to determine the existence of the activity points. The innovation of this project is that the method of high-temperature manual intervention used to make the changes of the surface active points of carbon black, which can provide convenience for exploring effectively the active groups and location points. The purpose of this project is to determine the positions of carboxyl, phenolic hydroxyl and ester groups on the surface of carbon blacks and then identify the activity of crosslinking. Generally, we can put forward a new method to study the activity of carbon blacks based on SPM tip force curve, which could guide the surface modification of new carbon materials such as fullerene, carbon nanotube and graphene. Therefore, when a new generation of carbon black reinforcing materials is developed under a balanced consideration of particle size, structure and activity, the reinforcing performance of green tires can be improved significantly.

近年来，受到绿色轮胎的勃兴与欧盟轮胎标签法的推动，炭黑这一最古老的碳材料得到了快速发展，新品种大量涌现，占据了补强填料的统治地位，但其补强机理特别是有关的活性理论没有明显的突破。本项目以炭黑表面含氧基团与活性相关性为突破口，提出建立基于针尖化学及其力曲线的炭黑活性点的表征方法，拟依次增加炭黑表面的酸性含氧基团，然后让针尖与炭黑聚集体接近或远离，发生原子间吸附与排斥作用，记录吸/斥力循环作用过程（力曲线与摩擦力曲线），解析炭黑表面的力曲线突变点数据。创新之处在于采用高温人工干预的方法使炭黑表面活性点倍增，为有效探寻炭黑的活性基团与活性位置点提供条件，预期结果是确定炭黑表面羧基、酚羟基、酯基等基团在表面的位置，并与结合胶实验结果进行比较，判断其交联活性。研究旨在提出一种基于作用力的炭黑活性研究方法，指导螺旋纳米碳、石墨烯等新型炭材料活化改性，为研制新一代橡胶补强材料提供指导。

近年来，受到绿色轮胎的勃兴与欧盟轮胎标签法的推动，工业炭黑新品种大量涌现，占据了补强填料的统治地位，但其活性点补强机制尚未厘清，理论远落后于应用，已成为制约绿色轮胎产业发展的瓶颈之一。本项目以炭黑表面含氧基团与活性相关性为突破口，通过利用原子力针尖力曲线表征技术解析了人工干预炭黑表面的活性点参数，在国内外率先建立了基于针尖化学及其力曲线的炭黑活性点的表征方法。研究首次发现：高结构炭黑表面活性点主要由炭黑表面含氧官能团和自身结构决定，普通炭黑表面活性点主要由表面含氧官能团决定。炭黑表面活性点主要分布于炭黑聚集体边缘处，并与炭黑边缘呈粘弹性有关。在此基础上，项目研究将针尖力曲线表征技术用于石墨烯、氧化石墨烯、纳米金刚石、鳞片石墨等碳材料的表面微观结构表征中，基于针尖力曲线研究了石墨烯的台阶、空洞等缺陷区域结构，为炭黑表面纳米凸起微区存在物理活性点提供佐证。最后，我们还将项目基础研究成果用于指导橡胶补强的新型碳材料——螺旋纳米碳纤维的活化改性研究，研制出了具有超强补强性能的螺旋碳填料，突破了炭黑填料补强橡胶的“魔鬼三角”力学性能提升的瓶颈问题，有望获得推广应用。