Preparation and Properties of Isobutylene-isoprene Rubber Containing Multifunctional Groups

Anovel method of introducing multifunctional groups onto butyl rubber (IIR) bycarbonyl addition reaction was investigated in this work. The resulting polymers(MFIIR) were characterized with FTIR, 1H NMR and GPC. The functional groupsC=O, CH=CH and -OH were introduced onto the butyl rubber backbone and themolecular weight of the resulting polymer was hardly any different from that of IIR. Thecuring properties of MFIIR and natural rubber (NR) and adhesive strength of bothsystems were studied and compared together by dynamic vulcanized analysis andtensile testing. Curing efficiency of MFIIR was improved significantly. TD5, TD10 andTD20 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 MFIIRincreased further with increasing the molar contents of NaH and MAH. The values ofTD5, TD10 and TD20 for 0.06/0.06 (mol/mol) of MFIIR reached their highest levels. Thetensile strength values of MFIIR samples were all between those of IIR and BIIR andthe stress at 300% elongation of MFIIR samples (6.1 MPa) were higher than those ofIIR (5.2 MPa) and BIIR (4.3 MPa). Peeling strength between MFIIR and NR reached1.20 N/mm which was higher than the value of peeling strength between thebrominated butyl rubber (BIIR) and NR. Dynamic mechanical properties and thermalbehaviour were also investigated by dynamic mechanical analysis and thermogravimetricanalysis. The decomposition temperature of MFIIR (404.6°C) was slightly lowerthan those of IIR (412.8°C) and BIIR (406.0°C) and thus, the modification processseems to have made insignificant effect on the thermal stability of IIR. Butyl rubber wasmodified successfully and a kind of modified IIR with much improved curing efficiencywas achieved through this method.