The solvent-free modification of butyl rubber in the medium of NaH

A novel improved butyl rubber (PMIIR) was prepared in a solvent free process, using sodium hydride (NaH) as activating agent and maleic anhydride (MAH) as modifier by processing modification technology in a conventional polymer processing equipment of an internal mixer. The structure of products was characterized by 1H NMR and FT-IR. In this process, polar sodium carboxylate functional group and unsaturated carbon–carbon double bonds were successfully introduced onto the chains of IIR on one step. The reaction mechanism was investigated in detail. It was found that the functionalization experienced two modified mechanisms: addition and substitution modified mechanisms. The reaction efficiency and content of MAH were evaluated. Polymer isolation and purification operations were reduced out due to the result of solvent free. Curing and mechanical properties of products were investigated. It was found that PMIIR has greatly increased curing rate due to the incorporation of polar group and carbon–carbon double bond.