Takeshi Nakato

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.

Synthesis of poly(succinimide) by bulk polycondensation of L‐aspartic acid with an acid catalyst

The bulk polycondensation of L-aspartic acid (ASP) with an acid catalyst under batch and continuous conditions was established as a preparative method for producing poly(succinimide) (PSI). Although sulfuric acid, p-toluenesulfonic acid, and methanesulfonic acid were effective at producing PSI in a high conversion of ASP, o-phosphoric acid was the most suitable catalyst for yielding PSI with a high weight-average molecular weight (M ω ) in a quantitative conversion; that is, the M ω value was 24,000. For the continuous process using a twin-screw extruder at 3.0 kg h - 1 of the ASP feed rate, the conversion was greater than 99%, and the M ω value was 23,000 for the polycondensation with 10 wt % o-phosphoric acid at 260°C. Sodium polyaspartate (PASP-Na) originating from the acid-catalyzed polycondensation exhibited high biodegradability and calcium-ion-chelating ability. The total organic carbon value was 86 ∼ 88%, and 100 g of PASP-Na chelated with 5.5 ∼ 5.6 g of calcium ion, which was similar to the value for PASP-Na from the acid-catalyzed polycondensation with a mixed solvent.

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.

Synthesis and radical polymerization of end-methacrylated poly(succinimide) leading to poly(aspartic acid) hydrogel

The polycondensation of aspartic acid in the presence of phthalic anhydride was carried out in mesitylene/sulfolane using o-phosphoric acid as a catalyst. The polymer yields were 91–78%, when 5–20 mol-% phthalic anhydride was added into the feed. The obtained poly(succinimide) carried a phthalic imide unit and a succinic acid unit as end groups. In the MALDI-TOF mass spectrum, the peak-to-peak distances between adjacent signals were 97.07 m/z, corresponding to the calculated value (97.07) of the succinimide unit. Poly(succinimide) was reacted with 2-(methacryloxy)ethyl isocyanate to give end-methacrylated poly-(succinimide), in which the end-functionality of the methacrylate group was ca. 1. End-methacrylated poly-(succinimide) was polymerized with ethylene glycol dimethacrylate using 2,2′-azoisobutyronitrile to give poly(succinimide) gel, which could be converted into water-absorbing poly(aspartic acid) hydrogel.