Preparation And Performance Of Multi-walled Carbon Nanotubes/Poly (Hydroxyaminoether) Composites

New epoxy-based thermoplastic poly(hydroxyaminoethers)(PHAE) are discussed here.The polymers are typically generated through reactions of arylene diglycidyl ethers(ADGE) with dinucleophilic amines and have various use purposes in a broading area due to its good thermal,mechanical and other properties.In order to enhance the performances of poly(hydroxyaminoether),multi-walled carbon nanotubes(MWNTs) are considered as potential reinforcer in nanocomposites,which have the combination of superior mechanical,electronic,thermal properties,and high aspect ratio.However,the difficulties are poor dispersion and low weak interactions between the CNTs and the polymer matrixes.In order to solve the questions about poor dispersion of MWNTs in polymer matrix,a method to functionalize the surface of MWNTs with PHAE was used in the paper.The MWNTs were modified firstly using 60 percent HNO₃ to be carboxyl functioned.Then carboxyl functionalization of MWNTs(MWNTs-COOH) were reacted with epoxy resin and triphenyl phosphine(TPP) in N,N-dimethyl formamide(DMF) to graft epoxy group onto the surface of the MWNTs.The next step,epoxy functionalization of MWNTs(MWNTs-EP) can be functioned with PHAE based on in situ polycondensation of ethanolamine and MWNTs-EP.Fourier transform infrared spectroscope(FT-IR),raman,transmission electronic microscope(TEM),scanning electron microscope(SEM),and thermal gravimetric analysis(TGA) were employed to characterize the functionalized MWNTs.The results indicated that epoxy resin and PHAE were successfully introduced onto the surface of the MWNTs,and the dispersion of nanomaterials were thus improved.Poly(hydroxyaminoehter) was synthesized by using relatively low molecular weight difunctional epoxy resin and ethanolamine as monomers.MWNTs/PHAE composites were prepared based on in situ polycondensantion of MWNTs-EP and ethanolamine in one step.TGA and DSC analysis demonstrated that the thermostability and glass transition temperature(Tg) of composites were improved with the MWNTs-COOH contents increased.SEM images of the cross-section of the nanocomposites exhibited a good dispersion,which was helpful to improve the interfacial interaction of the nanotubes and the matrix.Upon increasing MWNTs-COOH in the matrix,the mechanical properties of MWNTs/PHAE nanocomposites were greatly improved.The tensile strength of nanocomposite containing 1.5%MWNTs-COOH was up to 46.9MPa,52.8%higher than the pure poly(hydroxyaminoether).Finally,we compared the results between "graft from" and "graft to" in preparing MWNTs/PHAE and prefer "graft from".