title: Improved synthesis with high yield and increased molecular weight of poly(alpha,beta-malic acid) by direct polycondensation.
abstract: The development of synthetic biodegradable polymers, such as poly(alpha-hydroxy acid), is particularly important for constructing medical devices, including scaffolds and sutures, and has attracted growing interest in the biomedical field. Here, we report a novel approach to preparing high molecular weight poly(malic acid) (HMW--PMA) as a biodegradable and bioabsorbable water-soluble polymer. We investigated in detail the reaction conditions for the simple direct polycondensation of l-malic acid, including the reaction times, temperatures, and catalysts. The molecular weight of synthesized alpha,beta-PMA is dependent on both the reaction temperature and time. The optimum reaction condition to obtain alpha,beta-PMA by direct polycondensation using tin(II) chloride as a catalyst was thus determined to be 110 degrees C for 45 h with a molecular weight of 5300. The method for alpha,beta-PMA synthesis established here will facilitate production of alpha,beta-PMA of various molecular weights, which may have a potential utility as biomaterials.
authors.affiliation: Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan. kajiyama.Tetsuto@nims.go.jp
authors.forename: Tetsuto
authors.initials: T
authors.lastname: Kajiyama
authors.forename: Hisatoshi
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Taguchi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kataoka
authors.forename: Junzo
authors.initials: J
authors.lastname: Tanaka
mesh_terms: D008293:Malates / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D008970:Molecular Weight; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D008293:Malates; D011108:Polymers; C121060:poly(malic acid)