The Preparation Of Nah/mah System Modified Butyl Rubber And The Co-vulcanization With SBR

Butyl rubber（IIR）is an important commercial polymer with many desirable andexcellent properties, such as good ozone, oxygen, and heat aging resistance. Inparticular, for its intensive side methyl groups, it has superior gas impermeability andoutstanding ability to absorb mechanical energy, so IIR can be applied in manyimportant fields. However, the structure of IIR also leads to many negative properties,for instance, its compatibility with unsaturated rubbers and adhesive property are notgood.In this paper, a new processing modified IIR (PMIIR) was reported. It wasprepared by solvent-free bulk modified method in rubber processing equipment usedthe sodium hydride (NaH) as active agent and maleic anhydride (MAH) as modifyingagents. In this way, polar sodium carboxylate functional group and unsaturatedcarbon-carbon double bonds were successfully introduced onto the chains of IIR.PMIIR maintained the excellent properties of butyl rubber. At the same time, PMIIRvulcanization rate was effectively improved, co-vulcanized with other rubbers wereincreased.The molecular structure of PMIIR was characterized by infrared spectroscopy(FT-IR) and NMR spectra (1H-NMR). The reaction mechanism was investigated indetail. It was found that the functionalization had two modified mechanisms: additionreaction mechanism and substitution reaction mechanism. The reaction efficiency andcontent of MAH were evaluated. The thermal performance of PMIIR was explored byDMA, TG and we found that the introduction of polar groups on the thermal stabilityto be small. The vulcanization characteristics, mechanical properties, molecular weightand its distribution of PMIIR modified by different rotate speeds were analyzed.The experimental formula was discussed in this paper, different impacts ofactivator, accelerator and vulcanizer amounts on vulcanization characteristics andmechanical properties of PMIIR was analyzed. The blending technologies of PMIIR/SBR were studies. The results showed that PMIIR/SBR blends, whichwere prepared by precured method, were found to possess much improved mechanicalproperties compared to their conventional counterparts, the mechanical propertiesinitially increased with the extent of precuring, reached a maximum, and decreasedthereafter. All this showed that there was a best precuring degree. Morphologicalstudies using scanning electron microscopy substantiated the conclusions.