Study On Synthesis Of Amphiphilic Block Macromonomer And Its Properties

In this paper, Atom transfer radical polymerization of N-isopropylacrylamide was first studied. ethyl-2-bromo-propionate(EPN-Br), ethyl-2-chloro propionate(ECP) were selected as initiators, 2,2'-bipyridyl (bpy),N,N,N′,N″,N″-Penta-methyldiethylenetriamine (PMDETA) and tris(2-dimethylamino- ethyl)amine) (Me6TREN) as ligand, with CuCl as catalyst. The living character was investigated using different initiator/ligand system. It was found that when ECP was used as initiator,CuCl/Me6TREN were used as catalyze system, the polymerization was controlled, but when bpy was used as ligand, the polymerization was not controlled. It was found that ligand can clearly affect polymerization rate of NIPAAm monomer based on measurement of molecular weight of PNIPAAm under different ligand system by using gel permeation chromatography (GPC).A bulk atom transfer radical polymerization (ATRP) of styrene was studied using ECP as initiator, cuprous chloride as catalyst, PMDETA as ligand in toluene. Furthermore, a novel amphiphilic block copolymer (PSt-b-PNIPAAm) was synthesized using the PSt-Cl as macroinitiator, which initiates N-isopropylacrylamide (NIPAAm) reaction by ATRP. The structure and molecular weight of the PSt-b-PNIPAAm macromonomer were characterized by FTIR, 1H NMR and GPC.Atom transfer radical polymerization (ATRP) of styrene was studied using p-chloromethylstyrene (CMSt) as functional initiator, CuCl as catalyst, 2,2-bipyridine as ligand in toluene solution. CMSt had low initiating efficiency. Resulting polystyrene PSt-Cl(PSt:polystyrene) with a chloride atom in end has higher relative molecular mass than expected. However, relative molecular mass of PSt-Cl can be controlled by adjusting polymerization conditions. A novel amphiphilic block PSt-b-PNIPAAm macromonomer was synthesized using PSt-Cl as macroinitiator, which initiates N-isopropylacrylamide (NIPAAm) reaction by ATRP. Influence of solvent was studied and kinetic behavior in dimethyl sulfoxide was investigated. Structure and relative molecular mass of PSt-b-PNIPAAm were characterized by means of FTIR, H NMR and GPC. The results showed that the obtained copolymer was of PSt-b-PNIPAAm structure. In order to study the living character of C=C bond in PSt-b-PNIPAAm end, a homopolymerization of PSt-b-PNIPAAm is done by azobisisobutyronitrile as radical initiator in toluene. Relative molecular mass was increased from 6.6×103 to7.2×104 and 7.9×103 to 9.4×104 . It certify the reacting activity of C=C bond in end of PSt-b-PNIPAAm.