Good dispersibility of graphene in a medium or matrix is a critical issue in practical applications. In this work, graphene was functionalized using N-(4-hydroxyl phenyl) maleimide (4-HPM) via the Diels—Alder (DA) reaction by a one-step catalyst-free approach. The optimal reaction condition was found to be 90 °C for 12 h using dimethylformamide (DMF) as the solvent. FTIR, Raman spectroscopy, XPS and EDS proved that 4-HPM moieties were successfully grafted onto the surface of graphene. UV-vis and TGA confirmed that the grafting amount of 4-HPM was 3.75%–3.97% based on the mass of graphene. Functionalized graphene showed excellent dispersion stability when dispersed in common solvents such as ethanol, DMF, water, tetrahydrofuran and p-xylene. Meanwhile, functionalized graphene also exhibited pH sensitivity in aqueous due to the phenolic hydroxyls from the 4-HPM moieties. As a result of good dispersion stability and pH sensitivity, compared with graphene, functionalized graphene had better adsorption capacity for methylene blue (MB) from aqueous solution.

石墨烯在介质或基质中的良好分散性是实际应用中的关键问题。在这项工作中，通过Diels-Alder（DA）反应，使用N-（4-羟基苯基）马来酰亚胺（4-HPM）通过一步式无催化剂方法将石墨烯官能化。使用二甲基甲酰胺（DMF）作为溶剂，发现最佳反应条件为90°C持续12 h。FTIR，拉曼光谱，XPS和EDS证明4-HPM部分已成功接枝到石墨烯表面。UV-vis和TGA证实，基于石墨烯的质量，4-HPM的接枝量为3.75％–3.97％。当官能化的石墨烯分散在普通溶剂（如乙醇，DMF，水，四氢呋喃和对二甲苯）中时，表现出出色的分散稳定性。与此同时，由于来自4-HPM部分的酚羟基，官能化的石墨烯在水溶液中也表现出pH敏感性。由于具有良好的分散稳定性和pH敏感性，与石墨烯相比，官能化石墨烯对水溶液中亚甲基蓝（MB）的吸附能力更好。