Synthesis And Characterization Of Hyperbranched Crown Ether Polymer, And Transfer Polymerization Of Acrylonitrile Body Gene

This thesis includes two parts. One is about synthesis and characterization of hyperbranched polymer containing crown ether from an A2+B3 monomer system. The other is about group transfer polymerization of acrylonitrile in bulk at ambient temperature. The main results obtained are as follows.1. The following three kinds of hyperbranched polymers containing crown ether (B15C5-HP, B18C6-HP, and DB18C6-HP) were designed and synthesized via A₂+ B₃ approach (as shown Schemel).These hyperbranched polymers were characterized by FT-IR, NMR, GPC, and TG, respectively. The polymers exhibited good solubility in common organic solvents. The Mn and PDI were measured by GPC, calibrated with polystyrene standards; experimental results showed that the Mn and PDI of the hyperbranched polymers were varied with the values of [A2]/ [B3]. Thermal behaviors of the polymers were evaluated by TG All the polymers don't decompose under 325℃.Schemel Structure of hyperbranched polymer containing crown ether2. The morphology and self-assembly of hyperbranched polymer containing crown ether were studied by atomic force microscopy (AFM). The experimental results showed that the size of the images of B15C5-HP, B18C6-HP, and DB18C6-HP in dilute solution is about 80-100 nm (as shown Figure 1), 90-110 nm and 110-130 nm, respectively. Nanocolumns were observed about 5h after the addition of K+ in a B15C5-HP solution (as shown Figure 2). It was observed that the nanocolumn-like images grew longer and longer as the solution of these polymers in the presence of K+ stood longer. After keeping these solutions under ambient conditions for 7 days, the average length of the nanocolumn increased to 1350nm (as shown Figure 3), 900nm and 1560nm for B15C5-HP, B18C6-HP, and DB18C6-HP, respectively.. \Figure 1Figure 2Figure 3 3. The temperature sensitivity properties of these polymers B15C5-HP andB18C6-HP were investigated in aqueous solution. The low critical solution temperature (LCST) of the polymers was measured by curves of transmittance with changing of temperature. The LCST of B15C5-HP and B18C6-HP was 18.5 and 22.3 °C, respectively in the concentration of the polymers was 5 mg/mL. The experimental results showed that the structure of the polymers and the solution concentration ofpolymers can greatly affect their temperature sensitivity property.4. The liquid-liquid extraction of for alkali and alkaline earth metal cations by the polymers (B15C5-HP and B18C6-HP) was also studied and the complexing constants of the complexes were estimated. The polymers exhibit high selective extractability for K+, the order of the selectivity for alkali metal cations is K+>Rb+>Cs+>Na+>Li+; the order of the selectivity for alkaline earth metal cations is Ba2+>Sr2+>Mg2+>Ca2+. The B18C6-HP and B15C5-HP give the highest extractability for K+, the percentage of extraction are of 98.72% and 91.61% in the certain condition, respectively.5. The binding abilities of the polymers (B15C5-HP and B18C6-HP) for alkali and alkaline earth metal cations were evaluated by cation transport through liquid membranes. Experimental results showed that these polymers have greater transporting ability for sodium, rubidium, and cesium ions than for potassium and alkaline earth metal cations. The cation transport rates by polymer B15C5—HP decrease in the order: Na+>Rb+, Cs+> K+>Li+>Mg2+, Sr2+> Ba2+>Ca2+; The cation transport rates by polymer B18C6—HP decrease in the order: Rb+, Cs+ > Na+ > K+, Li+>Ba2+>Ca2+,Mg2+,Sr2+.6. The catalytic activity of these polymers B15C5-HP, B18C6-HP, and DB18C6-HP were investigated for substitution reaction of n-octyl bromide with potassium iodide and sodium iodide by gas chromatography. The experimental results showed that these hyperbranched polymers containing crown ether can be used as phase transfer catalysts. The activities of these polymers in catalyzing the reaction of n-octyl bromide with potassium iodide are greater than that of the reaction of n-octyl bromide with sodium iodide. The activities of these polymers decrease in the order: B18C6-HP>B15C5-HP> DB18C6-HP.7. The stability constants of the complexes formed by the polymers B15C5-HP, B18C6-HP, and DB18C6-HP with rare earth metal nitrates were determined byfluorescence spectrum. These complexes were very stable, and the logKs of B15C5-HP with thallium nitrate was up to 6.80.8. Group transfer polymerization of acrylonitrile was conducted in bulk at room temperature with 1, l,3-trimethyl-5-methylen-2, 6-dioxa-l-silacyclohexene (TMDSCH) as the initiator and tetrabutylammonium bibenzoate(TBABB) as the catalyst. The experimental results showed that the new GTP initiator give polyacrylonitrile in fairly good yield with well controlling of the molecular weight and polydispersity. The polydispersity of the polymers is narrower with values from 1.5 to 1.85, which is much smaller than that of PAN from a conventional GTP of AN, which was reported to be 3.79 (the classical GTP of AN. (with MTS as the initiator) required very low temperature (-50°C) and dilute solution conditions. This method can expand GTP for preparing PAN more efficiently.