Physicochemical properties of high-molecular-weight poly(α,β-malic acid) synthesized by direct polycondensation

Summary We studied high-molecular-weight α,β-PMA synthesized by polycondensation in order to find possible applications for biomaterials. Its solubility in different solvents, its hydrolysis and its acidity were also examined. The α,β-PMA molecular weight increased markedly up to 20 h and then decreased showing that the molecular weights for synthesized α,β-PMA depends on the reaction time. We prepared high-yield α,β-PMA with a molecular weight of 3600 by direct polycondensation using tin(II) chloride as a catalyst at 130°C for 20 hours and concluded that our method is suitable to synthesize higher molecular weight compounds of α,β-PMA. Received: 20 December 2002/Revised version: 18 February 2003/ Accepted: 22 February 2003 Correspondence to Tetsuto Kajiyama