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A lanthanum glutamic dithiocarbamate(La-GDTC) was synthesized. The vulcanization kinetic and crosslinking structure of styrene butadiene rubber (SBR)/La-GDTC/silica(SiO2) composites were studied via vulcanization kinetic simulation,swelling equilibrium and differential scanning calorimeter. Simulated curing parameters showed that the curing rate k2 of the SBR/La-GDTC/SiO2 composite was significantly higher than that of the SBR/La-GDTC composite. Also,swelling equilibrium test turned out that crosslinking density of SBR/LaGDTC/SiO2 composite evolved to higher level,compared to that of the SBR/La-GDTC composite. Ammonia modified swelling equilibrium interpreted both lanthanum ions and carboxyl groups could react with silanol groups of silica particles. Finally,vulcanization activation energies of SBR/La-GDTC/SiO2 composite were lower than that of SBR/La-GDTC composite,without respect to different approaches of the DSC measurement or Oscillated Disc Rheometer test. All the results showed that the lanthanum ions of La-GDTC could act as the metal ion catalyzer of sulfur vulcanization during the crosslinking process,which could be attributed to the unoccupied orbital of lanthanum ions. Therefore,a La-GDTC bridged structure between SBR and silica particles for the SBR/La-GDTC/SiO2 composite was suggested according to the experimental results.
The vulcanization kinetic and crosslinking structure of styrene butadiene rubber (SBR) / La-GDTC / silica (SiO2) composites were studied via vulcanization kinetic simulation, swelling equilibrium and differential scanning calorimeter. Simulated curing parameters showed that the curing rate k2 of the SBR / La-GDTC / SiO2 composite was significantly higher than that of the SBR / La-GDTC composite. Also, swelling equilibrium test turned out that the crosslinking density of SBR / LaGDTC / SiO2 composite evolved to higher level, compared to that of the SBR / La-GDTC composite. Ammonia modified swelling equilibrium test both lanthanum ions and carboxyl groups could react with silanol groups of silica particles. Finally, vulcanization activation energies of SBR / La-GDTC / SiO2 composite were lower than that of SBR / La-GDTC composite, without respect to different approaches of the DSC measurement or Oscillated Disc Rheometer test. All the results showed showed that the lanthanum ions of La-GDTC could act as the metal ion catalyzer of sulfur vulcanization during the crosslinking process, which could be attributed to the unoccupied orbital of lanthanum ions. Thus, a La-GDTC bridged structure between SBR and silica particles for the SBR / La-GDTC / SiO2 composite was suggested according to the experimental results.