Polymerization of Thermo-Responsive Poly(N-vinylcaprolactam): Effects of Temperature, Initiator and Monomer Concentration on Percent Conversion

Poly(N-vinyl caprolactam) (PNVCL) is a thermally responsive polymer. Its temperature-responsive properties make it an attractive candidate for various applications. A series of temperature-sensitive PNVCL were synthesized through free radical polymerization, using various of amount of Azobisisobutyronitrile (AIBN) as initiator agent and with reaction temperatures set at 60oC, 70oC, 80oC. The percent conversion of polymerization was determined using the Hubl method to investigate the effects of three factors: initiator agent concentration, monomer concentration and reaction temperature. Furthermore, the chemical structure and the responsiveness of the PNVCL polymer were analyzed using Fourier transform infrared spectroscopy (FTIR) and UV-vis spectrometer, respectively. The study revealed that increasing the reaction temperature, initiator concentration, and monomer concentration resulted in higher percent conversion of polymerization. Finally, the obtained polymer demonstrated thermal sensitivity within the range of 32oC to 38oC, which is close to human body temperature, suitable for biomedical applications.