凹凸于橡胶表面的炭黑颗粒对轮胎耐磨性的作用

The Effect of Carbon Black Particles Concave and Convex on the Surface of Rubber on the Wear Resistance of Tires

通过采用原子力显微镜研究分散于橡胶中的炭黑微观颗粒,测量了凸出在橡胶表面的炭黑聚集体高度值和包裹于炭黑周围的结合胶厚度值。研究发现其厚度变化范围为3 nm~7 nm,对应的炭黑原生粒径范围为20 nm~70 nm,而宏观耐磨性由大到小依次增强。较大粒径(70 nm左右)炭黑周围几乎观察不到结合胶,炭黑凸出高度值较大(约为20 nm~70 nm)。基于橡胶结合胶理论和磨粒磨损机理,提出一种新颖的炭黑补强解释。该理论的要点认为炭黑补强轮胎耐磨性归因于大量凸出在橡胶基体上的炭黑聚集体颗粒提供的表面硬质点,这些硬质点与地面接触,从而保护了基体橡胶不因高速摩擦而磨损。炭黑原生颗粒和橡胶基体的固定可通过一层结合胶实现。结合胶在受外力产生摩擦时能够提供弹性,能够将部分炭黑颗粒埋藏起来,而另一部分炭黑颗粒则仍然凸出于基体表面抵制耐磨,外力撤除后,其又恢复正常。

The carbon black micro-particles distributed in rubber are studied by using atomic force microscope(AFM).The height of carbon black aggregates protruding from the surface and the thickness of the binding rubber are measured.The study found that the binding rubber reveals a thickness ranges from 3 nm to 7 nm,and the corresponding primary carbon black shows a particle size ranges from 20 nm to 70 nm.Meanwhile,the abrasive resistance increased accordingly with the particle size decrease.Moreover,there is almost no binding rubber around the larger size carbon black(about 70 nm),and the protrusion height of carbon black is larger(about 20 nm to 70 nm).Based on the rubber binder theory and abrasive wear mechanism,a novel explanation of carbon black reinforcement is proposed.The main point of this theory is that the abrasive resistance of carbon black reinforced tire is attributed to the surface hard points provided by a large number of carbon black aggregate particles protruding from the rubber matrix.When these hard spots are in contact with the ground,thus they can protect the base rubber from rapid friction and wear.The fixation of the primary carbon black particles and the rubber matrix can be achieved by a layer of bonding glue.The binding rubber can provide elasticity when friction occurs under external force.It will hide part of the carbon black particles,while the other part of the carbon black particles still protrude from the surface of the matrix to resist wear.After the force is removed,it will return to normal.