海洋工程材料团队
[研究进展]王少柏同学通过PVA的氧化和缩酮化实现了可逆聚缩酮网络的制备(相关成果发表在European Polymer Journal)
发布时间: 2020-12-18 浏览次数: 161

Title:Benign Oxidation of PVA for Configuration of Reversible Polyketal Networks



Polyvinyl alcohol (PVA) is a reactive polymer since there are abundant hydroxyl groups so various chemical transitions are feasible for PVA. In this study, we utilized the oxidation of PVA followed with a ketalization to achieve the configuration of reversible polyketal networks. The oxidation of PVA was performed by using a benign oxidation system in which hydrogen peroxide acts as the green oxidant and p-toluene sulfonic acid (TSA) as the catalyst. Both fully oxidized PVA (polyketone, PK) and partially oxidized PVA (PVA-OXI) were obtained by controlling the oxidation time. Polyketals (PKLs) were prepared by ketalization of PVA with PK, or by selfketalization of PVA-OXI. Under the catalysis TSA, only dark PKLs were obtained. However, with ionic liquid [BMIm]HSO4 as the catalyst, PKLs were colorless and transparent. The PKLs originated from a feed ratio of PVA/ PK = 4/1 (w/w) seems tougher than other samples. When the PKL films were hydrolysed at 90 °C and recasted, the recycled (or reprocessed) PKL films appears the same as the fresh one, from the appearance to the chemical structure, and further to the mechanical properties. PKLs can be prepared by self-ketalization as well from PVAOXI but the mechanical properties of the obtained PKLs seem not as good as those from ketalization of PVA and PK. The discoveries in this work open a door to easy but efficient modification of OH-abundant polymers, especially for polysaccharides.

 

文章链接:https://doi.org/10.1016/j.eurpolymj.2020.110050