Masayuki Tomida

Convenient synthesis of high molecular weight poly(succinimide) by acid-catalysed polycondensation of l-aspartic acid

Abstract Poly(succinimide) (PSI) was synthesized by acid-catalysed polycondensation of l -aspartic acid. Polycondensation proceeded at a reaction temperature of above ca . 160°C, and a PSI with the highest weight-average molecular weight, 64 300, was obtained using a mixed solvent of mesitylene and sulfolane (w/w, 7 3 ) and phosphoric acid. Poly(aspartic acid), which was produced by alkali-hydrolysis of PSI, exhibited higher biodegradability than that originated from thermally polycondensed aspartic acid. After 28 days, biochemical oxygen demand/theoretical oxygen demand (BOD/TOD) and dissolved organic carbon for catalytic PASP were 82 and 89%, respectively, and 26 and 46% for thermal PASP.

Preparation conditions and properties of biodegradable hydrogels prepared by γ-irradiation of poly(aspartic acid)s synthesized by thermal polycondensation

Abstract Poly(aspartic acid) (PAsp) hydrogels have been prepared by the γ-irradiation of PAsp produced by thermal polycondensation reactions with an acid catalyst. The effects of the molecular weight of PAsp, pH, concentration of PAsp in the aqueous solution and dosage of γ-irradiation on the PAsp hydrogel preparation were investigated. PAsp hydrogels were prepared in the case when the PAsp weight-average molecular weight was 95 000, the pH of the solution was 7.5 or higher, the concentration of the solution was 5–10 wt/vol%, the dosage of γ-irradiation was 32 kGy or more and the preparation of PAsp solutions was done under N 2 . On the other hand, PAsp with low-molecular weight ( M w = 15 000) could not form hydrogel by γ-irradiation. The swelling of PAsp hydrogels in deionized water and artificial urine was measured. The maximum swelling by deionized water was 3400 g-water/g-dry hydrogel. Biodegradation of the hydrogel was checked using the activated sludge (Japanese Industrial Standards (JIS) K6950 method) indicating that the hydrogel showed about 50% biodegradation for 28 days.

Novel method of synthesizing poly(succinimide) and its copolymeric derivatives by acid-catalysed polycondensation of L-aspartic acid

Abstract High molecular weight poly(succinimide) was quantitatively synthesized by polycondensation of l -aspartic acid using a catalytic amount of o -phosphoric acid in the mixed solvent of mesitylene and sulfolane. In addition, under similar conditions, l -aspartic acid and ω-amino acid produced an organic solvent-soluble poly(succinimide- co -ω-amino acid), which melted below the decomposition temperature.

Synthesis and characterization of poly(succinimide-co-6-aminocaproic acid) by acid-catalyzed polycondensation of L-aspartic acid and 6-aminocaproic acid

The polycondensation of L-aspartic acid (ASP) with 6-aminocaproic acid (ACA) using o-phosphoric acid produced poly(succinimide-co-6-aminocaproic acid). The yield of the MeOH-insoluble copolymer decreased from 99 to 52% and that of the MeOH-soluble one increased from 9 to 47%, with increasing molar ratio of ACA in the monomer feed. The compositions of the succinimide (SCI) unit in the MeOH-insoluble and -soluble copolymers tended to be higher than those of ASP in the monomer feed. The copolymers with the 35 mol % SCI units or above were soluble in DMSO, DMF, and conc-H2SO4, but those with the 20 and 21 mol % SCI units were soluble only in conc-H2SO4. The melting temperature appeared for the copolymers with less than 76 mol % SCI units. Poly(succinimide-co-6-aminocaproic acid) was easily hydrolyzed to yield poly(aspartic acid-co-6-aminocaproic acid), and it exhibited biodegradability toward activated sludge.

SYNTHESIS AND CHARACTERIZATION OF POLY(ASPARTIC ACID) AND ITS DERIVATIVES AS BIODEGRADABLE MATERIALS

ABSTRACT Three types of modified poly(aspartic acid)s, such as poly(aspartic acid-co-aminocarboxylic acid) (4), alkylamine modified poly(aspartic acid) (5) and crosslinked poly(aspartic acid) (6), were synthesized and calcium-ion chelating ability, hygroscopicity and water absorption were evaluated. The calcium-ion chelating ability of 4 depended on the kind of aminocarboxylic acids and the content of aminocarboxylic acid in the copolymer. The highest value was 3 times higher than that of poly(acrylic acid) with a Mw of 14000. The highly modified PASP, e.g., 50 mol% lauryl amine modified poly(aspartic acid), showed the highest by grogroscopicity among homopoly(aspartic acid)s and modified poly(aspartic acid)s. The maximum swelling of poly(aspartic acid) hydrogel prepared by the γ-irradiation of homopoly(as-partic acid) was 3400 g-deionized water/g-dry hydrogel.