Sushko Rymma, Filimon Marlena, Dannert Rick, Elens Patrick, Sanctuary Roland, Baller Jörg
Physics and Materials Science Research Unit, Laboratory for the Physics of Advanced Materials, University of Luxembourg, 162A avenue de la Faїencerie, L-1511, Luxembourg.
Nanotechnology. 2014 Oct 24;25(42):425704. doi: 10.1088/0957-4484/25/42/425704. Epub 2014 Oct 3.
Elastomers filled with hard nanoparticles are of great technical importance for the rubber industry. In general, fillers improve mechanical properties of polymer materials, e.g. elastic moduli, tensile strength etc. The smaller the size of the particles, the larger is the interface where interactions between polymer molecules and fillers can generate new properties. Using temperature-modulated differential scanning calorimetry and dynamic mechanical analysis, we investigated the properties of pure styrene-butadiene rubber (SBR) and SBR/alumina nanoparticles. Beside a reinforcement effect seen in the complex elastic moduli, small amounts of nanoparticles of about 2 wt% interestingly lead to an acceleration of the relaxation modes responsible for the thermal glass transition. This leads to a minimum in the glass transition temperature as a function of nanoparticle content in the vicinity of this critical concentration. The frequency dependent elastic moduli are used to discuss the possible reduction of the entanglement of rubber molecules as one cause for this unexpected behavior.
填充有硬纳米颗粒的弹性体对橡胶工业具有重要的技术意义。一般来说，填料可改善聚合物材料的机械性能，如弹性模量、拉伸强度等。颗粒尺寸越小，聚合物分子与填料之间相互作用产生新性能的界面就越大。通过温度调制差示扫描量热法和动态力学分析，我们研究了纯丁苯橡胶（SBR）和SBR/氧化铝纳米颗粒的性能。除了在复数弹性模量中观察到增强效应外，有趣的是，约2 wt%的少量纳米颗粒会导致负责热玻璃化转变的弛豫模式加速。这导致在该临界浓度附近，玻璃化转变温度作为纳米颗粒含量的函数出现最小值。利用频率依赖的弹性模量来讨论橡胶分子缠结可能减少的情况，这是导致这种意外行为的一个原因。
