Marx Philipp, Wiesbrock Frank
Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria.
Chair of Chemistry of Polymeric Materials, Montanuniversitaet Leoben, Otto-Gloeckel-Strasse 2, 8700 Leoben, Austria.
Polymers (Basel). 2021 Mar 6;13(5):806. doi: 10.3390/polym13050806.
Commonly, volumetric shrinkage occurs during polymerizations due to the shortening of the equilibrium Van der Waals distance of two molecules to the length of a (significantly shorter) covalent bond. This volumetric shrinkage can have severe influence on the materials' properties. One strategy to overcome this volumetric shrinkage is the use of expanding monomers that show volumetric expansion during polymerization reactions. Such monomers exhibit cyclic or even oligocyclic structural motifs with a correspondingly dense atomic packing. During the ring-opening reaction of such monomers, linear structures with atomic packing of lower density are formed, which results in volumetric expansion or at least reduced volumetric shrinkage. This review provides a concise overview of expanding monomers with a focus on the elucidation of structure-property relationships. Preceded by a brief introduction of measuring techniques for the quantification of volumetric changes, the most prominent classes of expanding monomers will be presented and discussed, namely cycloalkanes and cycloalkenes, oxacycles, benzoxazines, as well as thiocyclic compounds. Spiroorthoesters, spiroorthocarbonates, cyclic carbonates, and benzoxazines are particularly highlighted.
通常情况下，聚合过程中会发生体积收缩，这是由于两个分子间的平衡范德华距离缩短至（明显更短的）共价键长度所致。这种体积收缩会对材料性能产生严重影响。克服这种体积收缩的一种策略是使用在聚合反应过程中表现出体积膨胀的膨胀单体。这类单体具有环状甚至寡环状结构单元以及相应紧密的原子堆积。在这类单体的开环反应过程中，会形成原子堆积密度较低的线性结构，这会导致体积膨胀或至少减小体积收缩。本综述简要概述了膨胀单体，重点是阐明结构 - 性能关系。在简要介绍用于量化体积变化的测量技术之后，将介绍并讨论最主要的几类膨胀单体，即环烷烃和环烯烃、含氧杂环、苯并恶嗪以及硫杂环化合物。特别突出介绍了螺原酸酯、螺原碳酸酯、环状碳酸酯和苯并恶嗪。
