Study On Synthesis And Properties Of Novel Block Copolymers

In this paper, a solusion atom transfer radical polymerization (ATRP) of tert-butylmethacrylate (tBMA) was first studied. Ethyl-2-chloro-propionate (ECP) was selected as initiator, 2,2'-bipyridyl (bpy) and N,N,N′,N″,N″-penta-methyldiethylenetriamine (PMDETA) as ligand, with CuCl as catalyst in DMF. It was found that ligand could clearly affect polymerization rate of tBMA monomer based on measurement of molecular weight of PtBMA-Cl by using gel permeation chromatography (GPC) under different ligand system. The polymerization regulations were compared for different systems. The number average molecular weight (Mn) of PtBMA-Cl could be controlled from 1.8×103 to 1×104 g/mol by varying the ratio of monomer to initiator in range of 1:25 to 1:100, and distribution of molecular weight (Mw/Mn) kept low than 1.30. The structure of the PtBMA-Cl was characterized by fourier transform infrared (FTIR) and nuclear magnetic resonance (1H-NMR). It was found that the obtained PtBMA-Cl had a specific structure.A solution ATRP of 4-vinylpyridine (4VP) was then studied using resulting PtBMA-Cl as macroinitiator, CuCl as catalyst, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazamacrocyclote- tradecane (Me6[14]aneN4) as ligand to form block copolymer. It was found that different solvent and ligand could affect the polymerization of 4VP. PtBMA-b-P4VP was characterized by FTIR, 1H-NMR and GPC. Furthermore, the hydrolysis of the synthesized PtBMA-b-P4VP was finished under room temperature to form block copolymer PMAA-b-P4VP. The self-assembly of this block copolymer in selective solvents was also studied. The focus is that the quaternization of the synthesized PtBMA-b-P4VP was finished. The quaternizated diblock copolymer was then hydrolyzed under room temperature to form hydrophilic PMAA-b-QPVPB diblock copolymer.Also, a solusion ATRP of 4VP was studied using CuCl as catalyst, p-chloromethylstyrene (CMSt) as functional initiator to synthesize macromonomer (St-P4VP) in the presence of bpy, PMDETA or Me6[14]aneN4 as ligand. Mn of St-P4VP could be controlled in a range from 2.0×103 to 1×104 g/mol by varying the ratio of monomer to initiator from 1:25 to 1:100. The structure was characterized by FTIR and 1H-NMR. In order to study the living character of C=C bond in St-P4VP end, a homopolymerization of St-P4VP is done. Mn was increased from 2.90×103 to 2.88×104, 6.11×103 to 5.8×104. It means that the C=C bond in end of St-P4VP has high reacting activity. The macromonomer with a halogen atom in end can initiate polymerization of new monomer which is expected to obtain diblock macromonomer.