树状桥联半受阻酚类抗氧剂的合成与抗氧化性能

从端基为胺基树状大分子出发, 合成了一种具有多个半受阻酚抗氧化基团、 结构对称的树状桥联半受阻酚类抗氧剂. 元素分析、 傅里叶变换红外光谱(FTIR)、 氢核磁共振波谱(¹H NMR)、 质谱(MS)和冰点降低法证实合成的树状桥联半受阻酚类抗氧剂的化学结构与理论结构一致, 纯度较高. 采用1,1-二苯基-2-苦基肼(DPPH)法和差热扫描量热(DSC)法研究了树状桥联半受阻酚类抗氧剂的抗氧化性能, 并与相应的树状桥联全受阻酚类抗氧剂进行了对比. 研究结果表明, 树状桥联半受阻酚类抗氧剂清除DPPH自由基的活性不仅与清除体系中抗氧剂的浓度有关, 而且与清除时间有关; 清除时间为30 min时的抗氧化能力是清除时间为400 min时抗氧化能力的近2倍. 树状桥联半受阻酚类抗氧剂的半受阻效应使其在DPPH体系和HDPE树脂中的抗氧化能力均优于其相应的树状桥联全受阻酚类抗氧剂.

Synthesis and Antioxidant Capacity of Dendrimer Bridged Antioxidant with Semi-hindered Phenolic Groups†

A dendrimer bridged antioxidant with semi-hindered phenolic groups and symmetrical structure was synthesized using 1.0G dendrimer as raw material. The structure and the purity of the dendrimer bridged antioxidant with semi-hindered phenolic groups were verified by elemental analysis, Fourier transform infrared spectoscopy(FTIR), ¹H nuclear magnetic resonance spectroscopy(¹H NMR), mass spectrometry(MS) and cryoscopic method. The antioxidant capacity of the dendrimer bridged antioxidant with semi-hindered phenolic groups was evaluated by the 1,1-diphenyl-2-picrylhydrazine(DPPH) assay and differential scanning calorimetry(DSC) method, and its antioxidant capacities was compared with those of the corresponding dendrimer bridged antioxidant with total-hindered phenol groups. The results showed that the free radical scavenging activities of the dendrimer bridged antioxidant with semi-hindered phenolic groups were affected not only by the antioxidant concentration but also by the reaction time. The antioxidant activity at the scavenging time of 30 min was about twice of which at the scavenging time of 400 min for the dendrimer bridged antioxidant with semi-hindered phenolic groups. Because of the semi-hindered phenolic effect, the antioxidant capacity of the dendrimer bridged antioxidant with semi-hindered phenolic groups was superior to that of the corresponding dendrimer bridged antioxidant with total-hindered phenolic groups in DPPH system and high density polyethylene(HDPE) resin.