Study On Preparation Of Graphene Oxide/Brominated Butyl Rubber Isolation Structure Composite And Properties Of Hydrogen Barrier

Facing the problems of environmental pollution and energy crisis,hydrogen energy has broad application prospects due to its clean,high energy density and abundant reserves.However,hydrogen and its isotopes are extremely permeable and can cause harm to personnel and the environment after leakage.Therefore,it is of great significance to prepare materials with high barrier properties.At present,polymer materials have been widely used in gas barriers,especially composite materials prepared by adding two-dimensional sheet fillers have excellent barrier properties.Graphene and its derivatives graphene oxide?GO?have physical properties such as large diameter-to-thickness ratio,gas impermeability,and excellent mechanics,making them ideal two-dimensional lamellar fillers.Especially GO has good dispersibility and easy modification properties,used to prepare polymer-based nanocomposites.According to the theory of gas permeation,the dispersion effect and distribution state of GO in polymers have a great influence on the barrier properties of materials,especially when the orientation and isolation structures are formed in polymers.The permeation path becomes tortuous,and the barrier properties of the polymer composite material are improved.In this paper,the bromobutyl rubber?BIIR?with good airtightness is selected as the matrix material,GO is used as the filler,and after two steps of electrostatic action and pH flocculation,GO/BIIR composites with orientation alignment structure and PDDA-GO/BIIR composites with isolation structure are prepared by hot pressing.In this paper,flake graphite was used as the raw material.First,GO was prepared by the improved Hummer method,and then the poly dimethyl diallyl ammonium chloride?PDDA?was used as a modifier,the GO was positively modified by electrostatic interaction and?-?interaction at room temperature.The FTIR?Raman?Zeta potential etc.were characterizes the modification effect.The test results show that the prepared GO surface is rich in oxygen-containing groups.When the ratio of GO to PDDA is 1:13,the prepared PDDA-GO has good water dispersibility and the Zeta potential value reached 34.43 mV at pH=6.Using latex mixing method,BIIR was first prepared into BIIRL.PDDA-GO@BIIR was self-assembled by two steps of electrostatic interaction and pH flocculation,then PDDA-GO/BIIR composite and GO/BIIR composite were prepared by hot pressing.The morphology of the composite was characterized by optical microscope and scanning electron microscopy.The results showed that GO showed an ordered alignment structure in BIIR,while PDDA-GO showed an isolated structure in BIIR.The hydrogen permeability tests were performed on two structures and different filler contents in each structure,and the results showed that the hydrogen permeability coefficient of the GO/BIIR composite with the oriented structure continued to decrease with the increase in the amount of GO.The lowest permeability coefficient was 10.15 cm³?cm?m^-2?d^-1?bar^-1,which is about 45%lower than BIIR's 18.38 cm³?cm?m^-2?d^-1?bar^-1.The hydrogen permeability of the isolation structure PDDA-GO/BIIR composite with the increase of the amount of PDDA-GO,the coefficient shows a trend of first decline and then increase,reaching a minimum value of 9.03cm³?cm?m^-2?d^-1?bar^-1 at a dosage of 0.75%by weight,which is about 51%lower than BIIR.The PDDA-GO/BIIR composite with isolated structure has lower hydrogen permeability than the GO/BIIR composite with oriented structure,indicating that its gas permeation path is longer.The corresponding diffusion coefficient test results further prove this conclusion.Therefore,The isolation structure composite material has a longer gas permeation path,and has better gas barrier properties.