New Functional Polymeric Materials Based On The Hyperbranched Polyethylenimine

In this dissertation, the commercially available hyperbranched polyethylenimine (HPEI) polymers having a large number of amino groups were used as the main raw materials to prepare several kinds of functional polymeric materials,such as recoverable and reusable macroligands suitable for atom transfer radical polymerization (ATRP), solid sorbent for dyes, template for small-diametered gold nanoparticles (AuNP) and stabilizers for large-diametered AuNP The detail was as follows:1. Preparation of macroligands and their application in ATRPMagnetic macroligand MNP-HPEI for ATRP was prepared through the surface modification of Fe3O4 magnetic nanoparticle with HPEI In the ATRP of methyl methacrylate (MMA), the catalytic system based on the complex of MNP-HPEI with CuCl/CuBr₂ could control the polymerization rate of MMA, molecular weight and polydispersity in good mode Furthermore, the catalytic systemcould be recovered and reused several times through magnetic field2 Preparation, characterization and application of functional multiarm star polymersMacroinitiators derived from HPEI were used to initiate the ATRP of 2-hydroxylethyl methacrylate (HEMA), resulting in functional multiarm star polymerwith HPEI as core and poly(2-hydroxylethyl methacrylate) (PHEMA) as arms After optimization of the polymerization condition, a series of HPEI-b-PHEMAmultiarm star polymers with controlled molecular weight and relatively narrow polydispersity could be obtained HPEI-b-PHEMA polymers in the solid state could adsorb the anionic Methyl Orange and Congo Red dyes from water The adsoption capacities were related closely with the size of HPEI core, the length and number of PHEMA arms Moreover, stable small AuNPs with diameter in the range of 2-10nm could be prepared with HPEI-b-PHEMA as template Compared with the control experiments, it could be concluded that the integration of the plenty of amino groups of HPEI core and the hydroxyl groups of PHEMA arms was the key to control the size of AuNPs and stabilize the AuNPs for long time3 The application of amphiphilic hyperbranched polymers in stabilizing large AuNPsCore-shell type amphiphilic hyperbranched HPEI-C16 polymers were prepared through the modification of HPEI with palmitic acid Among these HPEI-C16 polymers, only those with high degree of substitution could effectively transfer 18nm diametered AuNPs from water into chloroform phase Compared with the linear polyethylenimine modified with plamitic acid (LPEI-C16), less HPEI-C16 polymers were required for the completely extraction of AuNPs from water into chloroform phase Moreover, the AuNPs stabilized by HPEI-C16 polymers in chloroform were more stable AuNPs stabilized by both HPEI-C16 and LPEI-C16 could heterogeneously catalyze the NaBH4 reduction of 4-nitrophenol The catalytic rate of AuNPs stabilized by HPEI-C16 polymers was slower than that of AuNPs stabilized by LPEI-C16 polymers;however, the AuNPs stabilized by HPEI-C16 polymers could be recycled more times...