| Polymer/ionic liquid(ILs)mixtures have received extensive attention as a new type of versatile material.This paper studied linear rheology and nonlinear rheology of concentrated solutions of non-hydroxyl-containing neutral polymer polyethylene oxide(PEO)and polymethyl methacrylate(PMMA)in ILs by systematic rheological methods,and rheological behaviors of hydroxyl-containing neutral polymers polyvinyl alcohol(PVA)and poly(4-vinylphenol)(PVPh)in ILs.The effects of polymer-ILs hydrogen bonding interaction on segmental dynamics and overall rheological behavior were investigated.The second chapter studied the linear rheology and nonlinear rheology of concentrated solutions of PEO and PMMA in ILs.In linear rheology,the linear viscoelasticities of PEO in 1-butyl-3-methylimidazolium hexafluorophosphate([Bmim][PF6])and 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide([Bmim][Tf2N])were studied,and the linear viscoelasticity of PMMA in [Bmim][Tf2N] was also studied.The main curve is obtained by the time-temperature superposition(TTS)principle.By comparing the temperature dependence of the horizontal movement factor a T(or free volume fraction)of the polymer melt,the segmental dynamics caused by the fine interaction inside the polymer melt were explored.On this basis,the effective glass transition temperature Tg,eff of PMMA in each solution was extracted by analyzing the dependence of the normalized terminal relaxation time on temperature.The contribution of polymer-ILs interactions to segmental dynamics was evaluated by comparing ILs solutions,conventional solutions,and theoretically predicted Tg,eff.The results imply that segmental dynamics of neutral polymers is retarded in ILs by oxygen-cation hydrogen bonding interaction compared with in conventional polymer solvents.Finally,in nonlinear rheology,the effects of polymer-ILs hydrogen bonding interaction on chain deformation under shear flow and large strain were studied by start-up shear test and step-strain nonlinear stress relaxation test,respectively.The results imply that the segment-cation hydrogen bonding interaction is still too weak to influence the nonlinear chain orientation/stretch under shear flow or large deformation,even though it plays an important role in segmental dynamics.The third chapter studied the rheological behavior of PVA and PVPh in ILs.The rheological behaviors of three different molecular weights of PVA in 1-allyl-3-methylimidazolium chloride([Amim]Cl)and 1-butyl-3-methylimidazolium acetate([Bmim][Ac O])were studied,through the steady shear test,calculated the zero shear viscosity,relaxation time and termination modulus of PVA/ILs,and analyzed the dependence of these parameters on the polymer concentration,and compared with the scaling theory prediction.In addition,the rheological behavior of PVPh in [Amim]Cl,[Bmim][Ac O] and 1-butyl-3-methylimidazolium tetrafluoroborate([Bmim][BF4])was also investigated compared with the PVA/ILs system.Through these studies,changes in the rheological behavior of hydroxyl-containing polymers caused by interaction with ionic liquids were evaluated.The results show that [Amim]Cl is a good solvent and ? solvent for PVA and PVPh at 25 °C,respectively,[Bmim][Ac O] is a ? solvent of PVA and PVPh at 25 °C.In this study,the polymer/ILs system with hydrogen bonding interaction was studied by rheological method,which supplemented the theoretical basis for the research of neutral polymer solution and its dynamic.The present data are expected to motivate the experimental study on dynamics of polymer/IL solutions with stronger interactions.At the same time,our research results are expected to attract the interest of researchers engaged in theoretical research and computer simulation in this field.Its developments that may emerge in the future are also highly desired. |
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