Preparation And Characterization Of Polyaspartic Acid

Polyaspartic acid (PASP) is a compound developed in recent years abroad, especially in America. It is an environment-friendly chemical product exhibiting novel biodegradation, non-toxicity, non-pollution. It will have good application for its excellent properties.The polysuccinimide was synthesized by means of pyrocodensation catalyze polymerization, using L-aspartic acid as a monomer. Polyaspartic acid was achieved by hydrolixation of polysuccinimide. The effect of temperature, time, catalyzer, reaction media and other condition on yield and quality were studied by orthogonal experiment designs. The viscometeric properties of Polyaspartic acid (PASP) in dilute solution was characterized. The [η] of PASP in dilute water and NaCl solution was measured, at the same time, the [η] of PSI in DMF was measured. The research results indicated that:(1) The amount of catalyzer plays the most important role in the synthesis mean.(2) The PASP belongs to polyelectrolyte with its ionized carboxyl. The η_sp/C and lnη_r/C of Polyaspartic acid ( PASP ) in dilute solution increased with the decrease of the solution concentration. So the Fouss equation of PASP was estimated, as follows:η_xp/C = 105 .26 (1 + 28.85C^1/2)^-1 , [ η ] = 105.26mL/g(3) The relationship between its reduced viscosity and polymer concentration didn't coincide with Huggins equation, which can be changed by addinglow-molecular-weight strong electrolyte such as NaCl with moderate ionic strength /, and herein the intrinsic viscosity [rj] was directly proportional to -} exponential of/.(4) The Mark-Houwink equation of PSI was estimated as follows: , mL/g(5) Repeat unit of PSI: "[C^CW, n=Mn(Psl>/97, Repeat unit of PASP: n=Mn(M.sp)/ll5. Polyaspartic acid was achieved by hydrolixation of polysuccinimid, the polymerization degree is no change, so the molecular weight of PASP may be calculated by following equation :Mna>ASP) = I I 5 X Mn(pS|)/97...