将十八烷基胺(ODA)和超支化聚酯(HBP)通过化学接枝的方式成功对氧化石墨烯(GO)进行改性,制备改性GO(GO-O和GO-H)。分别将改性前后的GO分散在不同溶剂(水、甲苯)中并静置3 d,考察改性前后GO在不同极性溶剂中的分散性。结果表明:GO的亲水性较强,亲油性差。由于在GO表面引入烷基链段,GO-O在水中的分散性变差,在非极性溶剂中的分散性变好。由于HBP支化分子结构以及多羟基的存在,GO-H在水中和极性溶剂中的分散性均不如GO-O。进一步将改性前后的GO加入环氧树脂(EP)中,制备一系列EP/GO复合材料,对比研究改性前后GO对EP固化行为、力学性能、动态力学性能的影响。结果表明:随着填料的加入,样品的固化温度降低,拉伸强度、断裂伸长率、玻璃化转变温度和储能模量均提高,改善幅度排序为EP/GO-H>EP/GO-O>EP/GO。GO-H的加入对EP复合材料性能的影响比GO-O更为显著,拉伸强度从纯EP的15.9 MPa提升至60.2 MPa,增加279%;断裂伸长率从纯EP的10.5%提升至17.9%,增加70.5%;储能模量从纯EP的1 186 MPa提升至1 703 MPa,提升幅度高达43.6%;玻璃化转变温度从纯EP的88.2 ℃提升至100.8 ℃。
Octadecylamine (ODA) and hyperbranched polyester (HBP) were successfully used to modify graphene oxide (GO) via chemical grafting, resulting in the preparation of modified GO (GO-O and GO-H). Both the modified and unmodified GO were dispersed in different solvents (water and toluene) and allowed to stand for three days to investigate their dispersibility in solvents of varying polarity. The results indicated that GO had strong hydrophilicity but poor hydrophobicity. Due to the introduction of alkyl chains on the GO surface, the dispersibility of GO-O in water deteriorated, while its dispersibility in non-polar solvents improved. Owing to the branched molecular structure and the presence of multiple hydroxyl groups in HBP, GO-H exhibited inferior dispersibility in both water and polar solvents compared to GO-O. Further, both the modified and unmodified GO were incorporated into epoxy resin (EP) to prepare a series of EP/GO composite materials, and the effects of GO on the curing behavior, mechanical properties, and dynamic mechanical properties of EP were comparatively studied. The results showed that with the addition of fillers, the curing temperature of the samples decreased, while the tensile strength, elongation at break, glass transition temperature, and storage modulus all increased. The improvement order was EP/GO-H>EP/GO-O>EP/GO. The addition of GO-H had a more significant impact on the properties of EP composites compared to GO-O. The tensile strength increased from 15.9 MPa for pure EP to 60.2 MPa with a 279% increase, the elongation at break increased from 10.5% for pure EP to 17.9% with a 70.5% increase, the storage modulus increased from 1 186 MPa for pure EP to 1 703 MPa with a 43.6% increase, and the glass transition temperature increased from 88.2 °C for pure EP to 100.8 °C.