Study On Synthesis And Properties Of Cationic Siloxane-modified Amphiphilic Polymers

We synthesized a siloxane quaternary ammonium salt with high surface activity.And a series of polymeric viscosity reducer were synthesized through aqueous free radical polymerization of siloxane quaternary ammonium salt,acrylamide(AM)and diallyl dimethyl ammonium chloride(DMDAAC).Especially we studied the synthetic process conditions and application methods of this viscosity reducer.The viscosity reducer can be self-emulsifying with low dosage and easy to use.It can meet the requirements of heavy oil exploitation with high viscosity reduction,high tolerance to temperature and salt,and dehydration after demulsification.Herein,The structures and properties of siloxane quaternary ammonium salt and corresponding polymer were further characterized,and we studied the influence to the reduction of the siloxane quaternary ammonium salt.This thesis mainly includes the following work:1.We synthesized a siloxane intermediate by hydrosilylation reaction using 1,1,1,3,3,5,5-Heptamethyltrisiloxane and 4-bromo-l-butene.The intermediate was used to synthesize N-2-(methacryloyloxy)ethyl]N,N-dimethyl-N-(heptamethyltrisilox-ane)butene ammonium bromide(S)through quaternization.The structure of monomer S was characterized by IR and 1HNMR spectra,and the surface activity was characterized by surface tension method and the steady state fluorescence.2.We synthesized three copolymers by aqueous polymerization of AM,DMDAAC and S,then the structure,composition and molecular weight of these copolymers were characterized by IR,1HNMR spectra,elementary analysis and static light scattering.3.The aggregation behavior of copolymer in aqueous solution was characterized by the measurements of hydrodynamic radius,surface tension,interfacial tension,and contact angle.The results showed that the PAS and PADS has great surface activity,interfacial activity and wettability,but the PAD not.when the concentration was 0.6 g/L.The viscosity reduction rate of PAS and PADS can reach 98.0%,while the viscosity reduction rate of PAD only can reach 94.0%.It was also found that the PAS has good salt resistance with high percentage of monomer S in the polymer,and the PAD and PADS have great salt resistance.The aging resistance test demonstrated that polymers still have good viscosity reduction property even after it was placed in 65?for 15 days.PAS and PADS can be used to decrease the stability of the emulsion and increase the dehydration rate,up to 85.0-90.0%in one hour,but the PAD was only 74.5%.By comparing the solution properties and viscosity reduction performance of PAS2,PADS5 and PAD,it was found that the monomer S can improve the surface and interface activity,wetability with the help of DMDAAC in the PADS5.Compared with PAS2 and PAD,the viscosity reduction efficiency,salt and aging resistance of the PADS5 improve a lot.The monomer S also destabilized the system benefitting the dehydration of the emulsion.PADS5 can also be used to decrease the stability of the emulsion and increase the dehydration rate.