Ultra high molecular weight polyethylene doped with iron through high energy mechanical alloying

ABSTRACT Doping polymers with metallic materials can improve significantly its use. Ultra high molecular weight polyethylene is known for its high resistance to abrasion and impact, and also for its friction coefficient, which is significantly lower than that of commercial steel and most polymeric materials. Therefore, this material presents high industrial demand despite its processing difficulty due to its high viscosity. One kind of polymer processing which has been widely used recently is the high energy mechanical alloying. This method provokes significant changes in the material, such as crystalline structure transformation, amorphization, formation of metastable phases, and nanostructuring, among others. In order to investigate the influence of iron dopant in structural characteristics of polymeric matrix, ultra high molecular weight polyethylene were doped with low concentrations (between 0.1 at.% and 1 at.%) of iron using the method of high energy mechanical alloying. The samples composition was characterized by X-Ray Diffraction Mössbauer Spectroscopy. A theoretical molecular modeling was carried out to simulate the iron presence in polymeric cell, which is in good agreement with the experimental results. Therefore, there is evidence that part of the iron promotes a crossed bond between the polymeric chains.

摘要：将金属材料掺杂至聚合物中，可显著提升其应用价值。超高分子量聚乙烯（Ultra High Molecular Weight Polyethylene）以优异的耐磨抗冲击性能著称，同时其摩擦系数显著低于商用钢材与多数聚合物材料。因此，尽管该材料因高黏度导致加工难度较大，但其工业需求量仍居高不下。当下应用愈发广泛的一类聚合物加工工艺为高能机械合金化（High Energy Mechanical Alloying），该工艺可对材料造成显著改变，例如晶体结构转变、非晶化、亚稳相生成与纳米结构化等。为探究铁掺杂剂对聚合物基体结构特性的影响，本研究采用高能机械合金化工艺，以低浓度（0.1原子百分比至1原子百分比）的铁对超高分子量聚乙烯进行掺杂处理。本研究通过X射线衍射（X-Ray Diffraction）与穆斯堡尔光谱（Mössbauer Spectroscopy）对样品成分进行了表征，并开展了理论分子建模以模拟铁在聚合物晶胞中的存在状态，该模拟结果与实验数据吻合良好。综上，有证据表明部分铁元素可促进聚合物链间形成交联键。