Preparation?Mechanisem And Blending With NR Of Processing Modified Butyl Rubber

Butyl rubber(IIR)is an important commercial polymer with many desirable and excellent properties,such as good ozone,oxygen,and heat aging resistance.In particular,for its intensive side methyl groups,it has superior gas impermeability and outstanding ability to absorb mechanical energy,so IIR can be applied in many important fields.However,the structure of IIR also leads to many negative properties,for instance,its compatibility with unsaturated rubbers and adhesive property are not good.The introduction of polar groups and double bonds to IIR can improve these properties and may bring about some new performances.In this paper,a novel modification to IIR in solvent free process was reported,in which sodium hydride(NaH)was used as activating agent and Maleic Anhydride(MAH)as modifier.In this way,a novel multi-functional IIR was prepared without the need for polymer isolation and purification operations.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 the curing rate of PMIIR has increased greatly due to the incorporation of polar group and carbon-carbon double bond.In this paper,the effect of the amount of NaH/MAH on the properties of 1.8mol%unsaturated IIR was discussed.The vulcanization characteristics and mechanical properties of PMIIR modified by different amount of NaH/MAH were analyzed.Rubber process properties and dynamic mechanical properties are aslo investigated.The results show that the curing rate of PMIIR,with different content of MAH,had increased greatly,and the rubber process properties improved a lot.The blending technologies of PMIIR/NR were studies.The PMIIR/NR rubber sealing materials were prepared by the selection of blending system and by the optimization of process.The aging resistence and mechanical properties referred to the method of the preparation of PMIIR/NR were analyzed.The results show that PMIIR/NR blends,which were prepared by precured method,were found to possess much improved mechanical properties as compared to their conventional counterparts,the tensile strength initially increased with the extent of precuring,reached a maximum,and decreased thereafter.The optimum precuring crosslink density that has to be given to the PMIIR phases has been determined.The curing characteristics,mechanical properties,aging resistant performance and RPA of precured and conventional PMIIR/NR with different amount of NaH/MAH were also studied.