Liu Xi-Qiang, Li Ruo-Han, Bao Rui-Ying, Jiang Wen-Rou, Yang Wei, Xie Bang-Hu, Yang Ming-Bo
State Key Laboratory of Polymer Materials Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu, 610065 Sichuan, China.
Soft Matter. 2014 May 28;10(20):3587-96. doi: 10.1039/c3sm53211a. Epub 2014 Mar 24.
The properties of polymer blends greatly depend on the morphologies formed during processing, and the thermodynamic non-equilibrium nature of most polymer blends makes it important to maintain the morphology stability to ensure the performance stability of structural materials. Herein, the phase coarsening of co-continuous, immiscible polyamide 6 (PA6)-acrylonitrile-butadiene-styrene (ABS) blends in the melt state was studied and the effect of introduction of nano-silica particles on the stability of the phase morphology was examined. It was found that the PA6-ABS (50/50 w) blend maintained the co-continuous morphology but coarsened severely upon annealing at 230 °C. The coarsening process could be divided into two stages: a fast coarsening process at the initial stage of annealing and a second coarsening process with a relatively slow coarsening rate later. The reduction of the coarsening rate can be explained from the reduction of the global curvature of the interface. With the introduction of nano-silica, the composites also showed two stages of coarsening. However, the coarsening rate was significantly decreased and the phase morphology was stabilized. Rheological measurements indicated that a particle network structure was formed when the concentration of nano-silica particles was beyond 2 wt%. The particle network inhibited the movement of molecular chains and thus suppressed the coarsening process.
聚合物共混物的性能很大程度上取决于加工过程中形成的形态，并且大多数聚合物共混物的热力学非平衡性质使得保持形态稳定性对于确保结构材料的性能稳定性至关重要。在此，研究了熔体状态下共连续、不相容的聚酰胺6（PA6）-丙烯腈-丁二烯-苯乙烯（ABS）共混物的相粗化，并考察了引入纳米二氧化硅颗粒对相形态稳定性的影响。发现PA6-ABS（50/50 w）共混物保持了共连续形态，但在230℃退火时严重粗化。粗化过程可分为两个阶段：退火初期的快速粗化过程和后期粗化速率相对较慢的第二粗化过程。粗化速率的降低可以从界面整体曲率的降低来解释。随着纳米二氧化硅的引入，复合材料也表现出两个粗化阶段。然而，粗化速率显著降低，相形态得到稳定。流变学测量表明，当纳米二氧化硅颗粒浓度超过2 wt%时形成了颗粒网络结构。颗粒网络抑制了分子链的运动，从而抑制了粗化过程。
