Novel Rare Earth Complex And Its Application In Rubber As Antioxidant

Ageing and anti-ageing of rubber is one of the most important problems in theoretical research and applied sciences of rubber. The current direction of development of rubber anti-ageing agent are high performance, multi-functional, environmental friendly and low-cost. Synthesis of new types of multi-functional rubber anti-ageing agent will play an important theoretical and practical part in rubber products and the development of rubber industry.Fourteen rare earth complexes with 2-Mercaptobenzimidazole were synthesized and characterized by IR spectra, elemental analyses, X-ray diffraction and thermal analyses. The results indicated that the composition of the complexes is REL2(OH)?XH2O (RE = La～Lu, except for Pm, L = 2-mercaptobenzimidazole, x =1 or 2). Natural rubber(NR) vulcanizates and styrene-butadiene rubber(SBR) vulcanizates were prepared with the rare earth complexes. The antioxidative properties and mechanisms of the rare earth complexes in the NR vulcanizates and SBR vulcanizates were analyzed and compared with antioxidant 4010NA and antioxidant MB.The NR vulcanizates with fourteen kinds of rare earth complexes were prepared according to the conventional processes. The antioxidative properties and mechanisms of the Sm(III) complex in the NR vulcanizates were analyzed by attenuated total-reflectance Fourier transform infrared (FTIR-ATR) spectroscopy, X-ray photoelectron spectroscopy (XPS), crosslinking density determination, mechanical testing and thermogravimetric analysis (TGA). It was found that the Sm(III) complex showed the significant antioxidative effect in the NR vulcanizates through two functions: the thioether bond which can decompose the peroxide and the Sm(III) ion which can capture and inactivate the oxy radicals. The apparent thermo-oxidation activation energy (E) of the NR vulcanizates were calculated by the Kissinger and Flynn-Wall-Ozawa methods, respectively. The results showed that the NR vulcanizate with the Sm(III) complex had higher thermo-oxidation activation energy than the samples with antioxidant 4010NA and antioxidant MB.The effect of the Sm(III) complex on the photo-ageing, ozone ageing and fatigue ageing of NR vulcanizates were investigated by attenuated total-reflectance Fourier transform infrared (FTIR-ATR) spectroscopy and optical microscopy. The anti-ageing stability of the NR vulcanizates were found to be improved markedly by the addition of Sm(III) complex. The comprehensive antioxidant effect of the Sm(III) complex was superior to that of antioxidant 4010NA and antioxidant MB, but the ozone-resisting performance of the Sm(III) complex was slightly lower than that of antioxidant 4010NA.The SBR vulcanizates with fourteen kinds of rare earth complexes were prepared according to the conventional processes. The antioxidative properties and mechanisms of the Sm(III) complex in the SBR vulcanizates were analyzed. It was found that the Sm(III) complex showed the significant antioxidative effect in the SBR vulcanizates. The apparent thermo-oxidation activation energy (E) of the SBR vulcanizates were calculated by the Kissinger and Flynn-Wall-Ozawa methods, respectively. The results showed that the SBR vulcanizate with the Sm(III) complex had higher thermo-oxidation activation energy than the samples with antioxidant 4010NA and antioxidant MB.The effect of the Sm(III) complex on the photo-ageing, ozone ageing and fatigue ageing of SBR vulcanizates were investigated by attenuated total-reflectance Fourier transform infrared (FTIR-ATR) spectroscopy and optical microscopy. The anti-ageing stability of the SBR vulcanizates were found to be improved markedly by the addition of Sm(III) complex. The comprehensive antioxidant effect of the Sm(III) complex was superior to that of antioxidant 4010NA and antioxidant MB, but the ozone-resisting performance of the Sm(III) complex was slightly lower than that of antioxidant 4010NA.