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.
Self-vulcanizing blends of phenol hydroxy silicone rubber (PHSR) and fluoroelastomer (FPM) were prepared. Vulcanized rubbers with lower glass transition temperature (Tg) were successfully obtained. The results of dynamic mechanical analysis (DMA) show that the vulcanized FPM/PHSR (10 phr) blend has only one Tg temperature, demonstrating the well compatibility between FPM and PHSR. The thermogravimetric analysis (TGA) demonstrates that the PHSR do little damage to the thermal stability of FPM. The vulcanization characteristics of the FPM/PHSR blends were analyzed by using oscillating disc rheometer (ODR). The results show that FPM/PHSR blends have smaller Smin values and longer scorch time than that of FPM with the same level of bisphenol AF curing agent. It means that FPM/PHSR blends have better processability and curing security. Better mechanical properties can be gained for FPM/PHSR blends at appropriate level of PHSR.
