Synthesis of polymers in nanoreactors: A tool for manipulating polymer properties
Synthesis of polymers in nanoreactors: A tool for manipulating polymer properties
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DOI：
10.1016/j.polymer.2020.123112
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发表时间：
2020-10
期刊：
影响因子：
4.6
通讯作者：
Haoyu Zhao;S. Simon
中科院分区：
文献类型：
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作者：
Haoyu Zhao;S. Simon
使用纳米反应器来限制单体和合成聚合物导致反应动力学和聚合物性质的变化，使得纳米限制成为操纵和工程化聚合物性质的潜在工具。在这个角度来看，我们涵盖了传统的nanofinition主机，nanopore-confined自由基，逐步增长，开环聚合，和分子量的变化，立构规整度，玻璃化转变温度（Tg），热稳定性，和电气性能。我们使用我们实验室研究的例子，以及文献中工作的比较，来说明驱动这些变化的竞争力，即纳米孔表面的分子分层或取向，分子和片段扩散减少，以及天然或表面官能化纳米孔表面上的化学部分引起的催化或抑制作用。发现大多数纳米约束聚合被加速，并且在自由基聚合的情况下通常产生更高的分子量和更高的全同立构规整度。如果聚合物和限制表面之间存在较强的相互作用，则纳米限制聚合物的Tg趋于增加，但观察到限制聚氰脲酸酯的凹陷;强调了去除未反应的单体并将结果与相同分子量和结构的散装材料进行比较的重要性。还提供了在纳米约束下合成的聚合物的增强的热稳定性和导电性的实例。
The use of nanoreactors to confine monomers and synthesize polymers results in changes in the reaction kinetics and polymer properties making nanoconfinement a potential tool for manipulating and engineering polymer properties. In this perspective, we cover conventional nanoconfinement hosts, nanopore-confined free radical, step-growth, and ring-opening polymerizations, and changes in molecular weight, tacticity, glass transition temperature (Tg), thermal stability, and electrical properties. We use examples from research in our laboratory, as well as comparisons of the work in the literature, to illustrate the competing forces that drive these changes, namely molecular layering or orientation at the nanopore surface, decreased molecular and segmental diffusion, and catalytic or inhibitory effects caused by chemical moieties on the native or surface-functionalized nanopore surface. The majority of nanoconfined polymerizations are found to be accelerated, and in the case of free radical polymerizations to generally yield higher molecular weights and higher isotacticity. Tgs for the nanoconfined polymers tend to increase if strong interactions exist between the polymer and the confinement surface, but depressions are observed for confined polycyanurates; the importance of removing unreacted monomer and comparing results to the bulk material of same molecular weight and structure is emphasized. Examples are also provided of enhanced thermal stability and conductivity of polymers synthesized under nanoconfinement.