Preparation And Properties Of Isobutylene-Isoprene Rubber Containing Multifunctional Groups

A novel method of introducing multifunctional groups onto butyl rubber (IIR) by carbonyl addition reaction was investigated in this work. The resulting polymers (MFIIR) were characterized with FTIR, H-1 NMR and GPC. The functional groups C=O, CH=CH and -OH were introduced onto the butyl rubber backbone and the molecular weight of the resulting polymer was hardly any different from that of IIR. The curing properties of MFIIR and natural rubber (NR) and adhesive strength of both systems were studied and compared together by dynamic vulcanized analysis and tensile testing. Curing efficiency of MFIIR was improved significantly. TD5, TD10 and TD20 of MFIIR for 0.02/0.02 (mol/mol) of NaH/MAH increased by 157%, 51% and 34%, respectively compared to that of IIR. Moreover, TD5, TD10, and TD20 of MFIIR increased further with increasing the molar contents of NaH and MAH. The values of TD5, TD10 and TD20 for 0.06/0.06 (mol/mol) of MFIIR reached their highest levels. The tensile strength values of MFIIR samples were all between those of IIR and BIIR and the stress at 300% elongation of MFIIR samples (6.1 MPa) were higher than those of IIR (5.2 MPa) and BIIR (4.3 MPa). Peeling strength between MFIIR and NR reached 1.20 N/mm which was higher than the value of peeling strength between the brominated butyl rubber (BIIR) and NR. Dynamic mechanical properties and thermal behaviour were also investigated by dynamic mechanical analysis and thermogravimetric analysis. The decomposition temperature of MFIIR (404.6 degrees C) was slightly lower than those of IIR (412.8 degrees C) and BIIR (406.0 degrees C) and thus, the modification process seems to have made insignificant effect on the thermal stability of IIR. Butyl rubber was modified successfully and a kind of modified IIR with much improved curing efficiency was achieved through this method.