We show in this paper that three-dimensional networks in bulk polyethylene (mean molecular weight: 350 000 g mol~(-1), polydispersity of 2.62) with a defined grafting density of side-chains of 9.6 percent can be revealed by spin-coating the gel-like swollen polymer onto a flat surface. The polymer contained side-chains with one (33 percent), two (20 percent), three (13 percent) and more (34 percent) carbon atoms. The polymer structure after spin-coating consists of bundles, droplets at interconnects and globules. The combined tapping mode and contact mode atomic force microscopy (AFM) is able to distinguish topological differences in interconnects, such as entangled junctions from simple crossings of polymer bundles. A solvent treatment of the polymer network on the sample surface reveals that some of the droplets are in fact superpositions of more than one droplet, indicating again that a three-dimensional network is collapsed to two dimensions. We have observed that polymer bundles do branch near such multiple droplets. Finally, the recorded lateral forces while scanning across a polymer bundle in contact mode might be useful to model the mechanical behaviour of polymer bundles. However, without a solid theoretical model it is difficult to translate the experimental data into meaningful materials properties.
展开▼
机译：我们在本文中显示，通过旋涂可以揭示散装聚乙烯中的三维网络（平均分子量：350 000 g mol〜（-1），多分散性为2.62），侧链的定义接枝密度为9.6％。将凝胶状溶胀的聚合物涂在平坦的表面上。聚合物含有一个（33％），两个（20％），三个（13％）和更多（34％）碳原子的侧链。旋涂后的聚合物结构由束，互连处的液滴和小球组成。结合的分接模式和接触模式原子力显微镜（AFM）能够区分互连中的拓扑差异，例如缠结和聚合物束的简单交叉。在样品表面上对聚合物网络进行溶剂处理后，发现一些液滴实际上是一个以上液滴的叠加，这再次表明三维网络已塌陷为二维。我们已经观察到聚合物束确实在这样的多个液滴附近分支。最后，在以接触模式扫描聚合物束时记录的横向力可能对建模聚合物束的机械行为可能有用。但是，如果没有可靠的理论模型，很难将实验数据转化为有意义的材料特性。
展开▼
