Preparation And Properties Of P (An-Mah),P(An-Amps-Am)via Aqueous Slurry Polymerization

Polyacrylonitrile (PAN) is widely used for its superior properties, and comonomers are usually introduced to improve its properties. In this paper, the P (AN-MAH) and P (AN-AMPS-AM) were prepared via aqueous slurry polymerization, maleic anhydride (MAH),2-acrylamide-2-methylpropanesulfonicacid (AMPS) and AM were used as comonomers, ammounium persulphate (APS) was used as initiator, and water was used as the reaction medium. The effect of monomer feed ratios on the conversion, the intrinsic viscosity and thermal properties of the copolymers were studied.To the P (AN-MAH) polymerization system, the results showed that the P (AN-MAH) copolymers had a conversion ranged from60.94%to94.50%and [η] ranged from51.1mL/g to77.3mL/g when the initiator concentration and total monomer concentration were0.05wt%and22wt%at60℃. The thermal properties of P (AN-MAH) were investigated by differential scanning calorimeter (DSC), thermo gravimetric analysis (TG). The DSC results showed that the P (AN-MAH) had lower starting temperature of exothermic peak, broader exothermic peak width and higher extent of cyclization reaction than these of PAN homopolymer. When the AN/MAH feed ratios was98/2, the starting temperature of exothermic peak declined to239.7℃, the exothermic peak width broadened to38.5℃, the exothermic quantity increased to606.3J/g.The TGA results showed that the decomposition temperature of P (AN-MAH) increased with the increasing of the content of MAH.Rheometer was used to study the rheological properties of P (AN-MAH)/DMSO solutions. Steady state rheological test and dynamic rheological test were chose to analyse the effects of shear rate/angular frequency, temperature, molecular and solid content by the viscoelastic behavior of P (AN-MAH)/DMSO solutions. The results showed that the solutions belonged to a pseudo plastic fluid, exhibiting a significant shear-thinning phenomenon. In low shear rates, the apparent viscosity decreased with the increasing temperature, opposited in high shear rate. The complex viscosity (G’) and complex modulus (G") decreased with the increasing of temperature. The apparent viscosity, complex viscosity and complex modulus increased with the increasing of Mη and solid content. In addition, the spinnability of the solutions was studied according to the value of apparent activation energy of viscose flow (△Eη) and structure viscosity index (△η). The results indicated that the value of△Eη increased with the increasing of solid content or Mη, decreased with the increasing of temperature.To the P (AN-AMPS-AM) polymerization system, the results showed that the P (AN-AMPS-AM) copolymers had a conversion ranged from74.3%to87.2%and [η] ranged from78.8mL/g to97.1mL/g when the initiator concentration and total monomer concentration were0.05wt%and22wt%at60℃.The thermal properties of P (AN-AMPS-AM) were investigated through DSC, TG. The DSC results showed that the P (AN-AMPS-AM) copolymers had lower starting temperature of exothermic peak, broader exothermic peak width and higher extent of cyclization reaction than these of PAN homopolymer. When the AN/AMPS/AM feed proportion was98/1/1, the starting temperature of exothermic peak declined to235.2℃, the exothermic quantity increased to612.1J/g. The TGA results showed that the decomposition temperature of P (AN-AMPS-AM) increased with the increasing of the content of AM under air atmosphere.