Preparation of high molecular weight poly(N-vinylcarbazole) in high yield by low-temperature precipitation polymerization of N-vinylcarbazole

To produce high molecular weight poly(N-vinylcarbazole) (PVCZ) with high conversion, N-vinylcarbazole (VCZ) was heterogeneously polymerized in methanol at 30, 40 and 50°C using a low temperature initiator, 2,2′-azobis(2,4-dimethylvaleronitrile) (ADMVN), and the effects of polymerization temperature and concentration of initiator and solvent on the polymerization behaviour and molecular parameters of PVCZ investigated. Globally, experimental results correspond to predicted ones. Low polymerization temperature using ADMVN and a heterogeneous system using methanol proved to be successful in obtaining poly(N-vinylcarbazole) (PVCZ) of high molecular weight and high conversion with small temperature rise during polymerization, although free radical polymerization by azoinitiator was used. The polymerization rate of VCZ in methanol at 30°C is proportional to the 0.88th power of ADMVN concentration. The molecular weight is higher and the molecular weight distribution is narrower with PVCZ polymerized at lower temperatures. For PVCZ produced in methanol at 30°C using an ADMVN concentration of 0.0001 mol/mol of VCZ, a weight average molecular weight of 1750 000 g mol^-1 is obtained, with a polydispersity index of 1.82.