On some aspects concerning solution-suspension polymerization
of N-vinylformamide (in English)
Polimery 2013, No 1, 14
N-vinylformamide (NVF), a blocked vinylamine monomer, has become an important reagent in the synthesis of water-soluble resins. NVF can be easily polymerized in aqueous solutions, in bulk, in suspension and by means of emulsions techniques. In the present paper an advantage was taken of the poor solubility of poly(N-vinylformamide) (PNVF) in organic solvents and a solution/precipitation polymerization was investigated. Toluene was used as a solvent for NVF. Polymerizations were carried out in three series differing by the type of initiator and temperature. In series I 2,2'-azobis(isobutyronitryle) (AIBN) was used, replaced in series II with benzoyl peroxide (BP) and in series III with a redox system BP/N,N-dimethylamino-p-toluidine (BP/DMAT). Optimal temperatures in series I and II were found to be 50 °C and 80 °C, respectively, whereas in series III the possibility was tested to polymerize at the room temperature (22 °C). At increasing initiator to monomer molar ratios outputs were growing up to 98 % in series I and II while simultaneously times of the cloud point appearances have become shorter. However, there is no distinct relation between molar masses of and initiator concentration. It is noteworthy that for all polymers obtained by the solution/precipitation technique all dispersity values were below 2 what is not so easy to achieve with other techniques.