Arrigo Rossella, Teresi Rosalia, Gambarotti Cristian, Parisi Filippo, Lazzara Giuseppe, Dintcheva Nadka Tzankova
Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università degli Studi di Palermo, Viale delle Scienze, Ed. 6, 90128 Palermo, Italy.
Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Viale T. Michel, 5, 15121 Alessandria, Italy.
Materials (Basel). 2018 Mar 5;11(3):383. doi: 10.3390/ma11030383.
The aim of this work is the investigation of the effect of ultrasound treatment on the structural characteristics of carbon nanotubes (CNTs) and the consequent influence that the shortening induced by sonication exerts on the morphology, rheological behaviour and thermo-oxidative resistance of ultra-high molecular weight polyethylene (UHMWPE)-based nanocomposites. First, CNTs have been subjected to sonication for different time intervals and the performed spectroscopic and morphological analyses reveal that a dramatic decrease of the CNT's original length occurs with increased sonication time. The reduction of the initial length of CNTs strongly affects the nanocomposite rheological behaviour, which progressively changes from solid-like to liquid-like as the CNT sonication time increases. The study of the thermo-oxidative behaviour of the investigated nanocomposites reveals that the CNT sonication has a detrimental effect on the thermo-oxidative stability of nanocomposites, especially for long exposure times. The worsening of the thermo-oxidative resistance of sonicated CNT-containing nanocomposites could be attributed to the lower thermal conductivity of low-aspect-ratio CNTs, which causes the increase of the local temperature at the polymer/nanofillers interphase, with the consequent acceleration of the degradative phenomena.
这项工作的目的是研究超声处理对碳纳米管（CNT）结构特征的影响，以及超声处理引起的碳纳米管缩短对超高分子量聚乙烯（UHMWPE）基纳米复合材料的形态、流变行为和热氧化抗性的后续影响。首先，对碳纳米管进行了不同时间间隔的超声处理，所进行的光谱和形态分析表明，随着超声处理时间的增加，碳纳米管的原始长度急剧下降。碳纳米管初始长度的减小强烈影响纳米复合材料的流变行为，随着碳纳米管超声处理时间的增加，其流变行为逐渐从类固体变为类液体。对所研究的纳米复合材料的热氧化行为的研究表明，碳纳米管超声处理对纳米复合材料的热氧化稳定性有不利影响，尤其是在长时间暴露的情况下。含超声处理碳纳米管的纳米复合材料热氧化抗性的恶化可能归因于低长径比碳纳米管的较低热导率，这导致聚合物/纳米填料界面处局部温度升高，从而加速降解现象。
