A new rubber functional agent with dithiocarbamate group

carboxyl groups and lanthanum ion

called lanthanum glutamic dithiocarbamate (La-GDTC)

was synthesized and its chemical structure was characterized by FTIR and element analysis.The interfacial interactions of SBR/La-GDTC/SiO2composites were measured by toluene swelling-equilibrium test under room temperature.The crosslinking density data of SBR/La-GDTC/SiO2 composites turned out

with the increasing loading of silica content

that the crosslinking density evolved to a high extent considerably

without respect to the obstructed effect of the silica particles on sulfur crosslink reaction.The swollen Gibbs free energy parameters of the composites G decreased dramatically and S increased obviously

both of which interpreted that the chemistry environment of the silica particles in the rubber hybrid composites changed to some extent

leading to a more heterogeneous network existed in the composites and a different chemical bonding structure between the rubber matrix and inorganic particles.Also

the interphase interaction parameter C

obtained from Kraus equations

was the value of 2.02 and verified the reinforcement between SBR and silica particles via the hydrogen bonds and chemical bonds between the La-GDTC and silica particles.The tensile strength

elongation at break and tear strength all pointed out that the mechanical properties of the La-GDTC system were much higher than those of the ZDC system.Also

in the SEM photographs

well-dispersed silica fine particles and more fluctuated surface of the La-GDTC-4 were attained

however

the silica clusters aggregation and smooth surface of the fracture were observed in the ZDC-4

implying that the interface interaction between the SBR/silica particles of the La-GDTC system was much stronger than that of the ZDC system.Based on the fore-mentioned experimental observation

an interphase structure between the rubber matrix and the inorganic particles was discussed.