| With the deep development of domestic oil fields,the number of deep and ultra-deep wells in low-permeability reservoirs is increasing,and deep-seated oil and gas resources are faced with features such as high water content,high temperature,high pressure,high stress,and high carbon dioxide,and the development and research of new types of downhole tools.New materials for the development of unconventional reservoirs are increasingly becoming the key to oil production.At present,the technical indicators of rubber sealing materials used as oil extraction tools have not yet met the technical requirements of the harsh environment of oil fields.The development of high-performance rubber sealing materials has important theoretical and practical application values,and it has a positive role in promoting the scientific and technological level of deep oil and gas resources development in China and its strategic significance.This work focused on the key technical challenges faced by unconventional oil and gas reservoirs for the transformation of materials.A variety of ultra-high saturated hydrogenated nitrile butadiene rubber?HNBR?was selected as the matrix material.Thermoplastic polyurethane elastomer?TPU?,monohydric oxyhydroxide was studied.The composite modification of HNBR with zinc?HZMMA?,silicon carbon and fluororubber?FKM?,the dilute oxygen aging mechanism of HNBR composites was proposed,the aging reaction kinetics was discussed,the aging reaction kinetics model was established,the processing conditions of rubber composites were optimized,and high-performance HNBR composites were processed.In the first part,a variety of reinforcing agents were used to modify HNBR composites.TPU itself has excellent mechanical properties,and TPU and HNBR have good compatibility.When TPU compounded HNBR,and the amount of TPU was 30phr,the tensile strength,tear strength,and 100%tensile strength of thermoplastic polyurethane elastomer modified HNBR composites all appeared extreme phenomenon,in which the tensile strength reached 29.8 MPa.The tear strength was 46.4 N·mm-1 and the tensile strength was 22.7 MPa.Silicon-carbon is a kind of reinforcing material with different structure from that of carbon black.Comparing with carbon black N550,the silicon-carbon reinforced HNBR composite has better toughness and tear strength,and the elongation at break reaches 194.5%.The fracture strength is as high as 38.2 N·mm-1,which is significantly higher than that of HNBR composites which N550 reinforced,and the silicon-carbon-reinforced HNBR composites have a lower permanent deformation rate?2.5%?.In the second part,the dilute oxygen aging behavior of HNBR composites and the lifetime prediction of HNBR/HZMMA composites were studied.The type of reinforcing agent exhibits different aging resistance to HNBR composites.The HZMMA-enhanced HNBR composites have the best aging resistance,followed by the N990/HZMMA synergistic enhancement,and the N990-enhanced HNBR composites are the worst.The higher the medium temperature,the better the aging resistance of the HZMMA reinforced rubber composites.The relation between the tensile strength???and the aging time?t?of the HZMMA-reinforced HNBR composite in the high temperature and dilute oxygen atmosphere is?=a?k t.Based on the tensile strength as the aging evaluation index,the theoretical lifetime of the HZMMA-reinforced HNBR composites at 150°C in the high temperature and dilute oxygen medium is about 3 years.The third part studies the aging mechanism of supersaturated HNBR composites.The FTIR results of the HNBR aging gum show that the characteristic vibration absorption band of the nitrile?-C?N?functional group gradually weakens with the aging time,and the absorption bands associated with the-C=NH functional group at 3300 cm-1 and 1600 cm-1 gradually become stronger..In a high temperature?>160°C?medium,the carbon atom linked to the-CN functional group easily loses hydrogen atoms to generate free radicals,and the free radicals immediately attack the-C?N functional group in the HNBR macromolecule and undergo a radical hydrogenation reaction to make-C?N is converted to-C=NH,forming chemical crosslinks.The higher the content of the-CN functional group,the more likely the above-mentioned chemical crosslinking reaction occurs at high temperatures,resulting in worse aging resistance.For example,the tensile strength of 1000L-type HNBR?CN content 44wt%?composites after aging at 200°C is lower than that of 2000L-type HNBR?CN content 36wt%?composites,2000LHNBR shows better high temperature aging resistance The above aging mechanism was verified here in.In the fourth part,the compatibility,mechanical properties and thermal oxygen aging of FKM/HNNR composites were studied.The TG and DSC results of the FKM/HNNR blends show that the composites containing less mass fractions of FKM in the HNBR matrix have better compatibility.The presence of a small amount of FKM rubber in HNBR increases the relative distance between HNBR macromolecules and weakens the Van der Waals force between HNBR macromolecules.The HNBR rubber composite material shows that FKM increases with the number of parts in a certain range and the material is pulled.The gradual decrease in tensile strength.When the mass ratio of the two is 90/10,the tearing strength and the elongation at break of the rubber compound appear the maximum at the same time,and the 100%elongation strength that is positively related to the cross-linking density shows a peak,while the rubber compound has the strongest resistance to oxygen aging. |
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