Study On Composite Technology And Degradation Behavior Of Degradable Polyurethane Elastomers

Driven by the goal of "carbon peaking and carbon neutrality",energy-saving and energy-efficient oil recovery technologies have increasingly become key breakthroughs in oil and gas development.At present,the development of soluble downhole tools is an important means to achieve production increase and emission reduction by staged fracturing in horizontal wells.Soluble downhole tools do not need to be replaced by drilling and milling,and the performance advantage of self-dissolving in a suitable working medium has become a key technology for green development of oil and gas resources,energy reduction and emission reduction.Nowadays,soluble downhole tools have been developed from soluble metal matrix materials to degradable rubber sealing materials.The development of fully degradable sealing materials has become a hot spot in the field of oil production engineering and has important research value.Focusing on the problem that the research and development foundation of degradable composite materials in my country is weak and cannot meet the requirements of oil and gas development,this paper uses polyester compounded polyurethane(MPU)with a faster degradation rate as the matrix material,and uses polyglycolic acid(PGA)doped hydrogenation Nitrile(PGA/HNBR)and polyurethane with slow degradation rate(MDW88-1)were compounded and modified to prepare a degradable polyurethane composite material with adjustable degradation rate.The degradable polyurethane composites were coated with the synthesized hydrophilic polyurethane resin,and the effect of the hydrophilicity of the coating film on the degradation behavior of the degradable polyurethane composites was studied.This thesis is mainly composed of the following three parts.The first part uses PGA/HNBR to modify MPU to prepare PGA/HNBR/MPU ternary composites.The effects of different dosages on the mechanical properties,degradation behavior,degradation mechanism and thermal stability of composites are studied.The results show that the more MPU in the PGA/HNBR/MPU ternary composite,the faster the degradation rate of the composite.When the dosage of HNBR is 40 phr,MPU is 60 phr,and PGA is 6 phr,at 100 °C high temperature hydrolysis after168 h,the mechanical retention rate is up to 31.3%;the addition of PGA can effectively reduce the hardness of the material,making HNBR more likely to swell and increase the degree of degradation;with the increase of HNBR content,the thermal stability of the material is improved.The degradation of the composite material in water at 100 °C is mainly due to the hydrolysis of the MPU soft segment ester group,while the HNBR does not degrade.The second part uses MDW88-1 with a slow degradation rate to compound MPU to prepare compounded kneaded polyurethane.The mechanical properties,degradation behavior,degradation mechanism and thermal stability of compounded kneaded polyurethane with different proportions are studied.The results show that the degradation time of 1-7 days has been achieved through the degradation laws of different proportions of compounded mixed polyurethane in high temperature aqueous medium at 100 °C.Due to the different filler systems of the two mixed polyurethanes,the degradation rate is The difference is that the higher the content of MPU,the faster the rate of decline of the composite material.When the content of MPU is 10 phr and MDW88-1 is 90 phr,when the material is soaked in high temperature medium water at100 °C for 144 h,the tensile property is 2.38 MPa.The performance decreased by 91.9%,which met the requirement of complete degradation in 7 days;when the composite material degraded,water absorption occurred first,which caused the mass to increase and then degrade and lose the mass.The degradation mechanism was also due to the hydrolysis of the soft segment ester group.The third part is to synthesize hydrophilic polyurethane resins with different contents of hydrophilic agent,to complete the physical coating of degradable polyurethane composite materials by water-based polyurethane film,and to study the quality and use ratio of hydrophilic coating film to MDW88-1/MPU,which is 90/ Effects of type 10 degradable polyurethane composites on degradation behavior,effects of castor oil double bond-terminated polyurethane resins on mechanical properties,degradation behavior,degradation mechanism,and thermal stability of composites.The research results show that the hydrophilicity of the polyurethane resin increases with the increase of the content of MDEA,and the water-blocking ability of the resin film gradually weakens with the increase of the content of MDEA.Compared with the uncoated samples,the degradation rate of the coated degradable composites in water at70 ? is greatly reduced.After soaking for 24 h,the mechanical properties of the degradable polyurethane composites coated with the polyurethane film without hydrophilic MDEA are maintained.The mechanical retention rate of the blank sample was 86.83%,while the mechanical retention rate of the blank sample was only 59.39%.The coating film played a role in delaying the degradation;the protective effect of the resin film in water at 100 °C was greatly weakened,and the high temperature accelerated the movement of water molecules,but it was still better than before.The degradation rate of the coated sample is low,and the tensile strength of the blank sample is lower than that of the coated degradable polyurethane after soaking for 24 h.The water blocking ability of the coating film is regulated by regulating the amount ratio of the chain extenders MDEA and BDO to ensure that the degradable polyurethane composite material meets different technical requirements.