Reeves Jennifer A, Allegrezza Michael L, Konkolewicz Dominik
651 East High Street, Oxford, OH, 45058, USA.
Macromol Rapid Commun. 2017 Jul;38(13). doi: 10.1002/marc.201600623. Epub 2017 Jan 3.
Vinyl ketone polymers, including phenyl vinyl ketone (PVK), are an important class of polymers due to their ability to degrade upon irradiation with ultraviolet light which makes them useful for a variety of applications. However, traditional radical methods for synthesizing PVK polymers give rise to poor control or are unable to produce block copolymers. This work uses reversible addition-fragmentation chain transfer polymerization (RAFT) and photochemistry to polymerize PVK. When visible blue radiation of 440 ± 10 nm is used as the light source for the photopolymerization, rapid polymerization and well-defined polymers are created. This RAFT method uses PVK as both monomer and radical initiator, exciting the PVK mono-mer by 440 ± 10 nm irradiation to avoid the use of an additional radical initiator. Once the poly-mer is synthesized, it is stable against degradation by blue light (440 ± 10 nm), but upon exposure to ultraviolet (UV) radiation (310 ± 20 nm) significant decrease in molecular weight is observed. The degradation is observed for all poly(PVK) materials synthesized.
乙烯基酮聚合物，包括苯基乙烯基酮（PVK），是一类重要的聚合物，因为它们在紫外线照射下能够降解，这使得它们可用于各种应用。然而，传统的自由基方法合成PVK聚合物时控制效果不佳，或者无法制备嵌段共聚物。这项工作使用可逆加成-断裂链转移聚合（RAFT）和光化学方法来聚合PVK。当使用440±10nm的可见蓝光作为光聚合的光源时，可以实现快速聚合并生成结构明确的聚合物。这种RAFT方法使用PVK作为单体和自由基引发剂，通过440±10nm的辐照激发PVK单体，从而避免使用额外的自由基引发剂。一旦聚合物合成，它对蓝光（440±10nm）具有抗降解稳定性，但在暴露于紫外线（UV）辐射（310±20nm）时，会观察到分子量显著下降。对于所有合成的聚（PVK）材料都观察到了这种降解现象。
