DPPH法研究聚烯烃抗氧剂的抗氧化能力及反应动力学

以DPPH法考察了4种聚烯烃抗氧剂对DPPH·的清除能力，并对聚烯烃抗氧剂清除DPPH·反应进行了动力学分析。结果表明，4种聚烯烃抗氧剂对DPPH·均具有良好的清除作用，清除能力随聚烯烃抗氧剂浓度的增加而升高，随清除反应时间的延长先增大后趋于稳定。抗氧化效率从大到小的4种聚烯烃抗氧剂顺序为抗氧剂1010、抗氧剂BHT、抗氧剂1076、抗氧剂1098。聚烯烃抗氧剂清除DPPH·反应属一级反应，反应温度对该清除反应的反应速率常数k及反应活化能Ea影响不显著；4种聚烯烃抗氧剂中清除能力最强的聚烯烃抗氧剂1010的反应活化能仅为7.49 kJ/mol，说明这4种聚烯烃抗氧剂清除DPPH·在室温下即能快速进行。

Study on the Antioxidant Capacity and Kinetics of Polyolefin Antioxidant by Using DPPH Method

Free radical scavenging abilities of four polyolefin antioxidants were evaluated by DPPH·assay. The analysis of the scavenging reaction kinetics of the polyolefin antioxidant was carried out. The results showed that the four polyolefin antioxidants had good DPPH· scavenging abilities. The DPPH·scavenging rate of polyolefin antioxidant gradually increased with the increase of the antioxidants concentration, and increased first and then became steady along with the scavenging time. The antioxidation efficiency of the four polyolefin antioxidants from high to low was in order of antioxidant 1010, antioxidant 1098, antioxidant BHT, antioxidant 1076. The scavenging reaction of four polyolefin antioxidants to DPPH·fit a first-order kinetic reaction, and the reaction temperature has little influence on the reaction rate constant k and the activation energy E_a. The activation energy of the antioxidant 1010, whose scavenging ability was strongest in the four polyolefin antioxidants, was only 7.49 kJ/mol, showing that the scavenging reaction could proceed rapidly at room temperature.