The effect of neodymium stearate （NdSt） on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was studied in the concentration range of 0 to 2 phr, and the relationship ...The effect of neodymium stearate （NdSt） on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was studied in the concentration range of 0 to 2 phr, and the relationship between structure and mechanical properties of ENR25 vulcanizates was also discussed. Neodymium sterate was synthesized by saponification of stearic acid with newly formed rare earth hydroxide m water medium, and the structure of NdSt was investigated by Fourier transform infrared spectroscopy （FTIR）. Crosslinking den- sity of vulcanized natural rubber was studied by equilibrium swelling method. The results indicated that the interaction force between carboxylic ion of NdSt prepared in the lab and Nd ion was mainly ionic bond through FTIR analysis. NdSt could accelerate the vulcanization of ENR25 and influence the network structure of ENR25 vulcanizates. The incorporation of 1 phr NdSt for ENR25 vulcanizatcs showed the optimal aging resistance.展开更多
The effect of neodymium stearate （NdSt） synthesized by saponification method on thermal degradation and thermo-oxidative degradation of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was investigated...The effect of neodymium stearate （NdSt） synthesized by saponification method on thermal degradation and thermo-oxidative degradation of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was investigated by thermogravimetric analysis （TGA）, and the structure of ENR25 vulcanized with NdSt after thermo-oxidative decomposition was characterized using Fourier transform infared spectroscopy-attenuated total-reflectance （FTIR-ATR）. The thermal degradation kinetic parameters of ENR25 with different loadings of NdSt were determined by Coats-Redfern method. The results showed that the thermal degradation of ENR25 in nitrogen was a one-step reaction regardless of NdSt content, whereas the thermo-oxidative degradation was a multiple-step reaction. The thermal and thermo-oxidative stability of the ENR25 vulcanizates with the addition of NdSt was higher than that of pure ENR25 vulcanizates. The ENR25 vulcanizates with the incorporation of 1 phr （per hundred parts of rubber） NdSt imparted the highest activa- tion energy （E） of thermal and thermo-oxidative degradation. This could be attributed to the many unoccupied orbits in rare earth Nd, which could capture the free radicals and make the epoxide groups stable in the process of thermal and thermo-oxidative degradation for ENR25.展开更多
This work studied possibilities of using lanthanum stearate（LaS t） as an antioxidant in epoxidized natural rubber containing 25 mol.% expoxidation（ENR25） compounds. For comparison purposes, two commercial antioxid...This work studied possibilities of using lanthanum stearate（LaS t） as an antioxidant in epoxidized natural rubber containing 25 mol.% expoxidation（ENR25） compounds. For comparison purposes, two commercial antioxidant 4010 NA and MB were also used. The influence of LaS t, antioxidant 4010 NA and MB on cure characteristics, mechanical properties, crosslink density, hot air aging and thermo-oxidative degradation were studied. The results indicated that the incorporation of LaS t and antioxidants could accelerate the vulcanization of ENR. The ENR vulcanizates with antioxidant MB had better mechanical properties than 4010 NA and LaS t. Compared with antioxidant 4010 NA and MB, the ENR25 vulcanizates with the addition of LaS t exhibited the best hot air aging resistance and thermo-oxidative stability.展开更多
基金Project supported by the National Program on Key Basic Research Project of China (973 Program,2010CB635109)Ministry of Science and Technology R&D research institutes (contract grantnumber:2008EG134285)
文摘The effect of neodymium stearate （NdSt） on cure and mechanical properties of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was studied in the concentration range of 0 to 2 phr, and the relationship between structure and mechanical properties of ENR25 vulcanizates was also discussed. Neodymium sterate was synthesized by saponification of stearic acid with newly formed rare earth hydroxide m water medium, and the structure of NdSt was investigated by Fourier transform infrared spectroscopy （FTIR）. Crosslinking den- sity of vulcanized natural rubber was studied by equilibrium swelling method. The results indicated that the interaction force between carboxylic ion of NdSt prepared in the lab and Nd ion was mainly ionic bond through FTIR analysis. NdSt could accelerate the vulcanization of ENR25 and influence the network structure of ENR25 vulcanizates. The incorporation of 1 phr NdSt for ENR25 vulcanizatcs showed the optimal aging resistance.
基金supported by National Program on Key Basic Research Project of China(973Program,2010CB635109)Ministry of Science and Technology R&D Research Institutes(2008EG134285)supported by the Fundamental Research Funds for Rubber Research Institute,CATAS(1630022013021,1630022012013)
文摘The effect of neodymium stearate （NdSt） synthesized by saponification method on thermal degradation and thermo-oxidative degradation of expoxidized natural rubber with 25 mol.% epoxidation （ENR25） was investigated by thermogravimetric analysis （TGA）, and the structure of ENR25 vulcanized with NdSt after thermo-oxidative decomposition was characterized using Fourier transform infared spectroscopy-attenuated total-reflectance （FTIR-ATR）. The thermal degradation kinetic parameters of ENR25 with different loadings of NdSt were determined by Coats-Redfern method. The results showed that the thermal degradation of ENR25 in nitrogen was a one-step reaction regardless of NdSt content, whereas the thermo-oxidative degradation was a multiple-step reaction. The thermal and thermo-oxidative stability of the ENR25 vulcanizates with the addition of NdSt was higher than that of pure ENR25 vulcanizates. The ENR25 vulcanizates with the incorporation of 1 phr （per hundred parts of rubber） NdSt imparted the highest activa- tion energy （E） of thermal and thermo-oxidative degradation. This could be attributed to the many unoccupied orbits in rare earth Nd, which could capture the free radicals and make the epoxide groups stable in the process of thermal and thermo-oxidative degradation for ENR25.
基金supported by Natural Science Foundation of Hainan Province(514217)Special Fund for Agro-scientific Research in the Public Interest(201403066)
文摘This work studied possibilities of using lanthanum stearate（LaS t） as an antioxidant in epoxidized natural rubber containing 25 mol.% expoxidation（ENR25） compounds. For comparison purposes, two commercial antioxidant 4010 NA and MB were also used. The influence of LaS t, antioxidant 4010 NA and MB on cure characteristics, mechanical properties, crosslink density, hot air aging and thermo-oxidative degradation were studied. The results indicated that the incorporation of LaS t and antioxidants could accelerate the vulcanization of ENR. The ENR vulcanizates with antioxidant MB had better mechanical properties than 4010 NA and LaS t. Compared with antioxidant 4010 NA and MB, the ENR25 vulcanizates with the addition of LaS t exhibited the best hot air aging resistance and thermo-oxidative stability.
