Influence of the chemical structure of para‐bridged group on the antioxidant behavior of hindered phenol antioxidants in HDPE resin

Abstract

A hindered phenol antioxidant with rigid para‐bridged group (antioxidant AP) was synthesized to study the effect of the chemical structure on the antioxidant properties of hindered phenol antioxidants in high density polyethylene (HDPE). Antioxidant behavior of series of hindered phenol antioxidants with different para‐bridged groups in HDPE resin was also investigated by the thermal oxidation experiment, the mobility test, and the long‐term accelerated thermal aging test. The results showed that the rigidity of para‐bridged group and the molecule size have the important influences on the antioxidant performance of hindered phenol antioxidants in the HDPE resin, and the antioxidant abilities of antioxidant AP and Irganox 1,330 with the aryl para‐bridged group was superior to Irganox 1,098 and 1.0G dendritic antioxidant with the alkyl para‐bridged group at the same testing conditions. Compared with the hindered phenol antioxidants with alkyl para‐bridged group, the hindered phenol antioxidants with aryl para‐bridged group have better thermal oxygen stability and less mobility in the HDPE resin. Irganox 1,010 with ester groups is prone to hydrolysis to increase the mobility rate in hot water and the migration resistance of hindered phenol antioxidants in n‐hexane. Moreover, the high content of phenolic OH group and the aryl para‐bridged group are favorable for improving the antioxidant performance of hindered phenol antioxidants.

Synthesis of the reactive hindered phenol antioxidant 3,5‐di‐tert‐butyl‐4‐hydroxyphenyl methyl isobutylene ester and its application in ABS resin

“…The antioxidant capabilities of the ABS/DBHMIE systems were investigated by measuring the oxidation induction temperatures. The temperature corresponding to the maximum exothermic peak was the oxidation induction temperature 24 . Figure 5a shows the DSC thermograms for the systems with various DBHMIE contents.…”

“…In contrast, the oxidation induction temperatures of the systems containing 0.3 and 0.5 wt% DBHMIE were 240.5 and 245.4°C, respectively, which were 10.8 and 15.7°C higher than that of the pristine ABS resin. The higher the oxidation induction temperature was, the stronger the thermal‐oxidative aging resistance of the material 24 . This result can be explained as follows: because the large tert‐butyl groups are electron‐donating groups, the hydrogen of the hydroxyl group in DBHMIE is very reactive and can be abstracted by free radicals such as R and ROO⋅ to form a phenoxy radical and prevent free radical damage to the ABS resin, thereby improving the antioxidant performance of the ABS resin.…”

“…The temperature corresponding to the maximum exothermic peak was the oxidation induction temperature. 24 Figure 5a shows the DSC thermograms for the systems with various DBHMIE contents. The oxidation induction temperatures were calculated from the DSC thermograms, and the results are shown in Figure 5b.…”

“…The higher the oxidation induction temperature was, the stronger the thermal-oxidative aging resistance of the material. 24 This result can be explained as follows: because the large tert-butyl groups are electron-donating groups, the hydrogen of the hydroxyl group in DBHMIE is very reactive and can be abstracted by free radicals such as R and ROOÁ to form a phenoxy radical and prevent free radical damage to the ABS resin, thereby improving the antioxidant performance of the ABS resin. The remaining component forms stable free radicals with the benzene rings, which will not undergo free radical chain reactions, thus inhibiting oxidation of the polymer chains.…”

Synthesis and antioxidant properties of a novel arylamine antioxidant

“…Hindered phenol and amine‐type antioxidants are the most typical representatives of primary antioxidants being extensively used in modern industry 23–25 . However, hindered phenol antioxidants show very poor antioxidant ability at evaluated temperature, which is a significant disadvantage of this type of antioxidants and greatly limits their more application in modern lubricant system 26,27 . Hence, amine‐type antioxidants have always been the research focus at present.…”