Advances in the Catalytic Hydrogenation and Properties of Unsaturated Polymers

Polymer reaction and performance improvement are one of the important contents in the field of polymer materials science and engineering, in which polymer catalytic hydrogenation is an important part of polymer reaction. We reviewed the research achievements on polymer hydrogenation over the past 70 years and studied the mechanism of the hydrogenation reaction from the aspects of performance changes before and after polymer hydrogenation, the catalyst preparation/structure–activity relationship, and polymer hydrogenation kinetics. We pointed out the difficulty in separation and unsatisfactory high-temperature adaptability of traditional homogeneous catalysts and first proposed four effects affecting traditional heterogeneous polymer hydrogenation: scale effect, conformation effect, viscosity effect, and adhesion effect. Based on the structure–activity relationship of polymers, we put forward the application direction of hydrogenated polymers at present. We found that using a new kind of nanometal catalyst (Pd/CNTs@FN) as hydrogenation catalyst can effectively reduce or eliminate the negative effects of these four effects on the polymer hydrogenation reaction, and it is easy to separate from the reaction system. The addition of CNTs can effectively increase the specific surface area of the catalyst and strengthen the interaction between reactants and catalyst. Subsequent research should focus on designing the multiscale structure and improving low-temperature activity of the catalyst, reducing process cost, and using green and efficient separation methods to eliminate adverse effects, create a green and efficient polymer reaction system, accelerate the industrialization of polymer hydrogenation process, and provide theoretical guidance for the research and development of new polymer materials.