Preparation And Properties Of Water-Soluble Polymers With Supramolecular Structure

The supramolecular systems constructed based on non-covalent interactions have the characteristics of self-assembly,self-healing,simple preparation,high stability,and excellent viscosity enhancement,and have good application prospects in the fields of biomedicine and oilfield chemistry.In the field of tertiary oil recovery,when polymer is injected into formation to displace crude oil,it will be affected by fluid dilution and rock mineral adsorption,and its viscosity increasing ability and oil displacement efficiency will be greatly reduced.Therefore,it is of great significance to develop a new type of oil displacement polymer that can form a stable spatial network structure at low concentration and has excellent viscosity.At the same time,the treatment of oily sewage generated after the oil flooding operation is also an urgent problem to be solved.At this stage,traditional cationic flocculants cannot meet the needs of sewage treatment.It is necessary to develop a new type of flocculant to optimize the flocculation process.In view of the problems of Polyacrylamide polymer in the field of oilfield chemistry,combined with the excellent properties of supramolecular systems,this paper prepared a series of ionic polymer/organic small molecule supramolecular composite systems based on electrostatic,hydrophobic,and hydrogen bond supramolecular forces.The selfassembly behavior and solution properties were studied in detail,and applied to the fields of oil displacement and flocculation.The main works are as follows:1.The copolymer SPAM was synthesized with acrylamide(AM)and 2-acrylamido-2methylpropanesulfonic acid(AMPS)as monomers,the structure of the polymer was characterized by 1H NMR spectra,FT-IR spectra,light scattering,and its synthesis process was optimized.the supramolecular composite system was prepared by electrostatic and hydrogen bonding between SPAM and organic amine.The viscoelasticity,temperature and salt resistance behavior of the Supramolecular complex system solution were measured by rheological means,and the oil displacement performance was evaluated.The results show that the electrostatic and hydrogen bonding between SPAM and organic amines can form a supramolecular system with a tighter spatial network structure,a larger hydrodynamic radius and a more significant viscosity increase,the system significantly improves the temperature resistant,salt resistant,shear resistant and viscoelastic properties of SPAM copolymer,the supramolecular system finally enhances the oil recovery rate by 16.7%,which is better than the oil displacement efficiency of SPAM.2.Three kinds of unsaturated hydrophobic monomers with different alkyl groups were prepared by amidation of methacryloyl chloride with octylamine,dodecylamine and octadecylamine,respectively,the hydrophobic associative polymers AAC8,AAC12 and AAC18 were prepared by micellar polymerization of AM,AMPS and hydrophobic monomers.The structure of the copolymer was characterized by 1H NMR spectra,IR spectra and light scattering.The supramolecular composite system was prepared by compounding copolymer with organic amines through electrostatic,hydrophobic association,hydrogen bonding multiple interactions.Using rotational viscometer,dynamic light scattering and other testing methods to explore the regulation of supramolecular composite system by different factors,and the solution properties and oil displacement effect of the hydrophobically associating copolymer/organic amine supramolecular composite system were investigated by viscosity,rheology and oil displacement tests.The results show that compared with the SPAM/organic amine supramolecular system,the introduction of hydrophobic association can significantly improve the temperature and salt resistance properties of the hydrophobically associating copolymer/organic amine supramolecular composite system,In addition,the spatial network structure strength and crosslink density of the supramolecular system constructed by various noncovalent bonds increase,so that the network structure becomes stable,and the shear resistance and viscoelasticity are improved.and when subjected to shear damage,the supramolecular system can quickly recover 93.5%of the viscosity,showing excellent shear recovery performance.At the same time,the supramolecular system can improve the recovery rate by 20.4%,and the oil displacement efficiency is better than that of the SPAM/organic amine supramolecular system.3.The water-soluble cationic copolymer PAD was synthesized with acrylamide and methacryloyloxyethyltrimethylammonium chloride as monomers.The structure of the copolymer was characterized by 1H NMR spectra,IR spectra,and elemental analysis.Combining it with organic acids to construct a supramolecular composite system based on electrostatic and hydrogen bonding.Nanoparticle size potentiometer and rotational viscometer were used to explore the regulation of the system by the molar ratio of potassium citrate to PAD.The influence of external factors on the flocculation effect was investigated through the test of oil removal rate and turbidity.The results show that compared with single flocculant,the supramolecular composite flocculant can adsorb and bridge more colloidal particles,and the flocculation effect is significantly improved.