Jovanovic Jelena D, Blagojevic Stevan N, Adnadjevic Borivoj K
Institute of General and Physical Chemistry, Studentski Trg 12-16/V, 11158 Belgrade, Serbia.
Faculty of Physical Chemistry, University of Belgrade, Studentski Trg 12-16, 11158 Belgrade, Serbia.
Polymers (Basel). 2023 Mar 3;15(5):1287. doi: 10.3390/polym15051287.
Composite hydrogels samples consisting of poly(methyl methacrylate/butyl acrylate/2-hydroxyethylmethacrylate) (poly-OH) and up to 60% reduced graphene oxide (rGO) containing rGO were synthesized. The method of coupled thermally induced self-assembly of graphene oxide (GO) platelets within a polymer matrix and in situ chemical reduction of GO was applied. The synthesized hydrogels were dried using the ambient pressure drying (APD) and freeze-drying (FD) methods. The effects of the weight fraction of rGO in the composites and the drying method on the textural, morphological, thermal, and rheological properties were examined for the dried samples. The obtained results indicate that APD leads to the formation of non-porous xerogels (X) of high bulk density (D), while FD results in the formation of highly porous aerogels (A) with low D. An increase in the weight fraction of rGO in the composite xerogels leads to an increase in D, specific surface area (SA), pore volume (Vp), average pore diameter (dp), and porosity (P). With an increase in the weight fraction of rGO in A-composites, the D values increase while the values of SP, Vp, dp, and P decrease. Thermo-degradation (TD) of both X and A composites takes place through three distinct steps: dehydration, decomposition of residual oxygen functional group, and polymer chain degradation. The thermal stabilities (TS) of the X-composites and X-rGO are higher than those of the A-composites and A-rGO. The values of the storage modulus (E') and the loss modulus (E") of the A-composites increase with the increase in their weight fraction of rGO.
合成了由聚（甲基丙烯酸甲酯/丙烯酸丁酯/甲基丙烯酸2-羟乙酯）（聚-OH）和高达60%的含还原氧化石墨烯（rGO）的氧化石墨烯组成的复合水凝胶样品。采用了氧化石墨烯（GO）片层在聚合物基质中热诱导自组装与GO原位化学还原相结合的方法。使用常压干燥（APD）和冷冻干燥（FD）方法对合成的水凝胶进行干燥。研究了复合材料中rGO的重量分数和干燥方法对干燥样品的质地、形态、热性能和流变性能的影响。所得结果表明，APD导致形成高堆积密度（D）的无孔干凝胶（X），而FD导致形成低D的高孔充气凝胶（A）。复合干凝胶中rGO重量分数的增加导致D、比表面积（SA）、孔体积（Vp）、平均孔径（dp）和孔隙率（P）增加。随着A-复合材料中rGO重量分数的增加，D值增加，而SP、Vp、dp和P值降低。X和A复合材料的热降解（TD）均通过三个不同步骤进行：脱水、残余氧官能团分解和聚合物链降解。X-复合材料和X-rGO的热稳定性（TS）高于A-复合材料和A-rGO。A-复合材料的储能模量（E'）和损耗模量（E"）值随着其rGO重量分数的增加而增加。
