The Synthesis Of Polycrylic Series Functional Microspheres

Due to their virtues, polyacrylic series functional polymer microspheres have been widely used in various areas. However, it is difficult and expensive to synthesize polyacrylic series spheres directly through conventional suspension polymerization. Thus, polyacrylonitrile spheres were prepared firstly, and converted to polyacrylamide (PAM) and polyacrylicacid (PAA) spheres through hydrolyzation; eventually, the polyvinylamine (PVAm) spheres were prepared through the Hoffmann degradation of PAM spheres.The influences of different conditions and different compositions of the reaction system on PAN spheres have been researched. The optimal reaction condition was 65℃and 160rpm, and the advisable composition was: BPO/AIBN as intiator, NaCl solution (NaCl/H 2 O=7/20 wt) as water phase and 3% crosslinker dosage. Through FTIR, NMR, XPS and SEM tests, it was demonstrated that these hydrolyzations of PAN spheres were successful, and the convert ratios were 64.2% (PAM) and 35.0% (PAA) respectively. The Hoffmann degradation of PAM spheres was proven to be successful by FTIR, NMR, and water content tests, and the convert ratio was 72.6%. The influence of NaClO solution dosage on the exchange capacity and adsorption capacity of PVAm spheres has been estimated. The results proved that the PVAm spheres prepared with 70mL NaClO solution possessed highest exchange capacity (15.3mmol/g) and adsorption capacity (426.4kU/g).Micron-sized PAM spheres have been prepared through the dispersion polymerization of acrylamide, and these PAM spheres exhibited regular shape and narrow dispersity. The sizes of over 70% PAM spheres were between 1.5-2.0μm, and the value of polydispersity index (PDI) was 1.17. Both of the shape and the PDI value of the PAM spheres were better than those reported by some other researchers. The average particle size of PAM spheres became larger with the increase of monomer concentration, the decrease of stabilizer concentration, the increase of initiator concentration and the decrease of ethanol/water ratio.