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采用DPPH法对脂肪二胺桥联受阻酚的抗氧化活性和清除反应动力学进行了研究。结果表明,脂肪二胺桥联受阻酚具有良好清除DPPH·的活性,随脂肪二胺桥联受阻酚浓度的增大和清除反应时间的延长,清除活性先快速降低随后变化较小;随着桥联基的增长,清除活性降低,即抗氧化活性降低,这表明脂肪二胺桥联受阻酚的桥联基越长,酚羟基提供氢质子的能力越差,清除自由基的活性越低。然而,该系列受阻酚在聚烯烃材料中,由于受体系相容性的影响,随着桥联基的增长,抗氧化活性反而增强。脂肪二胺桥联受阻酚清除DPPH·的反应为一级反应,且反应速率常数随着桥联基链的增长而降低。
The antioxidant activity and scavenging kinetics of aliphatic diamine bridged hindered phenols were investigated by DPPH method. The results showed that fatty diamine bridged hindered phenol had a good DPPH · scavenging activity. With the increase of the concentration of fatty diamine bridge hindered phenol and the extension of scavenging reaction time, the scavenging activity decreased rapidly at first and then changed little. The decrease of scavenging activity, that is, the decrease of antioxidant activity, indicates that the longer the bridging group of the aliphatic diamine bridging hindered phenol, the poorer the ability of the phenolic hydroxyl group to provide hydrogen protons and the lower the activity of scavenging free radicals. However, the series of hindered phenols in polyolefin materials, due to the compatibility of the system, with the growth of the bridging group, anti-oxidation activity increased. The reaction of aliphatic diamine bridging hindered phenol to scavenge DPPH · is a first-order reaction, and the reaction rate constant decreases with the increase of bridging-base chain.