Effect of Interfacial Area on Heterogeneous Free Radical Grafting of Vinyl Monomers in Supercritical Carbon Dioxide: Grafting of Acrylic Acid on Poly(vinylidenefluoride) Nanoparticles

摘要

The role of the polymer interfacial area on free radical grafting of acrylic acid (AA) onto poly(vinylidenefluoride) (PVDF) was studied at 65 degrees C using supercritical carbon dioxide (scCO(2)) as a solvent and swelling agent, benzoylperoxide (BPO) as chemical initiator and PVDF nanoparticles as polymer matrix. Under adopted conditions PVDF particles do not melt neither dissolve in the reaction medium and FTIR analyses performed on carefully washed nanoparticles confirmed the achievement of high grafting levels. The mass fraction of grafted AA increased with the grafting time and the BPO concentration while it decreased when the density of the fluid phase was enhanced. Collected results suggest that the grafting level obtained by free radical grafting of vinyl monomers onto solid polymer in scCO(2) can be significantly enhanced by increasing the interfacial area of the matrix. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41541.