The Controllable Preparation And Application In Plastification Of Dumbbell-shaped Polymer Brushes

How to realize the well-defined properties and functions of nanomaterials has been a hot topic for researchers.In recent years,polymer brushes have been regarded as a solution due to its controllability of structure and size.However,how to make the preparation for polymer brushes a universal and convenient process? Living radical polymerization could be a feasible way to deal with this urgent situation.In this paper,a series of dumbbell-shaped polymer brushes with variable structures were prepared by two living radical polymerization methods,which simply need mild conditions,afford a wide range of monomers and are lowcost.Firstly,a series of dumbbell-shaped polymer brushes with different backbone length and variable side chain length were synthesed by reversible addition-fragmentation chain transfer(RAFT)polymerization and atom transfer radical polymerization(ATRP)methods.The structure and properties of these polymer brushes were confirmed by nuclear magnetic resonance(NMR)spectroscopy,Fourier transform infrared(FT-IR)spectrometer,gel permeation chromatography(GPC),differential scanning calorimeter(DSC)and thermogravimetric analysis(TGA)characterizations.The results of NMR,FT-IR and GPC showed that different structures of dumbbell-shaped polymer brushes could be obtained by adjusting the feed ratio and duration of reactions.DSC and TGA curves indicated the thermodynamics data of dumbbell-shaped polymer brushes.In the second part,thermogravimetry was performed to analyze the thermal degradation kinetics for dumbbell-shaped polymer brushes by Kissinger and Flynn-Wall-Ozawa methods.It was found that the dumbbellshaped polymer brushes had a good thermal stability and the activation energy decreased with the increase of backbone length and side chain length.What's more,this part made a firm foundation for the subsequent processing experiments.Finally,the dumbbell-shaped polymer brushes processed with polystyrene as a kind of additive in different proportions(3 phr,5 phr,10 phr)to verify the decline of melt fluidity.The results demonstrated that the melt viscosity decreased with the ascending addition amount of polymer brushes,the decrease of polymer backbone and the increase of branches.The effect of dumbbell-shaped polymer brushes performed promising market potential compared with that of commercial plasticizer.