The Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria, 3010, Australia.
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
Macromol Rapid Commun. 2017 Oct;38(19). doi: 10.1002/marc.201700352. Epub 2017 Aug 10.
Molecular weight and dispersity (Ð) influence physical and rheological properties of polymers, which are of significant importance in polymer processing technologies. However, these parameters provide only partial information about the precise composition of polymers, which is reflected by the shape and symmetry of molecular weight distribution (MWD). In this work, the effect of MWD symmetry on thermal and rheological properties of polymers with identical molecular weights and Ð is demonstrated. Remarkably, when the MWD is skewed to higher molecular weight, a higher glass transition temperature (T ), increased stiffness, increased thermal stability, and higher apparent viscosities are observed. These observed differences are attributed to the chain length composition of the polymers, easily controlled by the synthetic strategy. This work demonstrates a versatile approach to engineer the properties of polymers using controlled synthesis to skew the shape of MWD.
分子量和分散度（Ð）会影响聚合物的物理和流变性能，这在聚合物加工技术中非常重要。然而，这些参数只能提供有关聚合物精确组成的部分信息，而分子量分布（MWD）的形状和对称性则反映了这一点。在这项工作中，展示了 MWD 对称性对具有相同分子量和 Ð 的聚合物的热性能和流变性能的影响。值得注意的是，当 MWD 向高分子量倾斜时，观察到玻璃化转变温度（T）升高、刚性增加、热稳定性提高和表观粘度增加。这些观察到的差异归因于聚合物的链长组成，这很容易通过合成策略来控制。这项工作展示了一种使用受控合成来倾斜 MWD 形状来设计聚合物性能的多功能方法。
