Synthesis of polyacrylonitrile using AGET-ATRP in emulsion

The technique of activators generated by electron transfer for atom transfer radical polymerization (AGET-ATRP) of acrylonitrile (AN) has been first attempted in emulsion using the procedure of “one-pot”, “two-step” with polyethylene glycol monooleyl ether (Brij 35) as surfactant, cupric chloride (CuCl2) as catalyst, hexamethylenetetramine (HMTA) as ligand, carbon tetrachloride (CCl4) as initiator and ascorbic acid (VC) as reducing agent. The polymerization proceeds in controlled/living manner as indicated by first-order kinetics of the polymerization rate with respect to the monomer concentration, linear increase of the molecular weight of polyacrylonitrile (PAN) with monomer conversion and narrow polydispersity. Monomer conversion increases initially with the increase of ligand HMTA and then decreases. The ratio of [AN1] to [AN2] at 1:3 not only gives better control on the molecular weight and the molecular weight distribution, but also provides a more rapid polymerization rate. The rate of polymerization shows a trend of increase along with CCl4 content. The apparent activation energy of the polymerization is calculated to be 46.6kJ/mol. Chain extension of PAN with AN was also carried out and the chain extended PAN with 20520 molecular weight and 1.36 polydispersity was successfully obtained. Kinetic plot for AGET ATRP of AN in emulsion AGET-ATRP of AN has first investigated in emulsion with HMTA as ligand, CCl4 as initiator and VC as reducing agent. The polymerizations have been successfully conducted in a controlled manner in the presence of air as evidenced by a linear first-order kinetic plot and linear increase of molecular weight with monomer conversion. [Display omitted] ► AGET-ATRP of AN is first investigated in emulsion. ► HMTA is used as ligand. ► Chain extension of PAN with AN verifies the living nature of the polymerization system.