Aging Performance And Mechanism Of Tetrafluoroethylene-propylene Elastomer Under The Environment Of Supercritical Water

Fluorine rubber is one kind of polymer materials,has a very important application in the field of the seals.Oil and gas field development projects are usually used in sub-critical water?SCW?to develop heavy oil,heavy oil in the development process requires the use of a large number of rubber sealing products,fluorine rubber has good heat resistance,oil and mechanical properties,one kind of elastomer that is expected to be used in heavy oil development.Therefore,the author studies the molecular structure of rubber materials with the low price of Tetrafluoroethylene-propylene Elastomer?FEPM?as the research object,deduces its aging process and contrasts with the aging structure under pure high temperature condition,and puts forward the unique reaction mechanism of supercritical water aging process.Critical rubber in the water and the use of supercritical water to eliminate fluorine-containing polymer materials to provide experimental and theoretical support.The effects of different co-crosslinking agents on the aging properties of tetra-fluoro-fluorinated rubber in supercritical water were also investigated.First of all,through the curing characteristics,mechanical properties and other tests to determine the co-crosslinking agent on the rubber in the supercritical water environment reinforcement role.It is found that the auxiliary crosslinking agent OVPOSS Volume change rate,tensile strength is almost unchanged,the rate of change in elongation rate slightly better.Then,the TAIC/DCP crosslinking system was selected,and the aging mechanism of the tetrafluorinated rubber was investigated by mechanical properties,swelling degree,XPS and ¹³C NMR of the FEPM after aging under different aging conditions.It was found that under the condition of different aging conditions,the cross-linking point of FEPM was broken,and the defluorination phenomenon was all.Under the air environment,the aging of FEPM was the combination of broken chain and crosslinking.Only the occurrence of chain reaction;water environment H⁺and OH^-easy to attack the unsaturated bond,resulting in broken chain;O₂ easily oxidized tetraprofluorinated rubber propylene chain part.Finally,the aging behavior of PDVB,g-C₃N₄ and FKM2603 in supercritical water was investigated.The results showed that at 300?,the four kinds of FEPM had different degree of reinforcement.When the temperature was above 325?,the effect of FKM2603 on the effect of FEPM was obvious.But PDVB only add 6 copies,FEPM original tensile strength of up to 20.8 MPa,the effect is significant.