Chain Extension and Enzymatic Degradation of Aliphatic Polyesters.

Shirahama, Hiroyuki; Aludin, M.S.; Kawaguchi, Yoshihide; Migita, Naho; Yasuda, Hajime

doi:10.5650/jos1996.46.1391

Cited by 5 publications

(9 citation statements)

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“…The molecular weights ( M n ) of polyesters except for DMA/BD polyester exceed 35,000, and are considerably higher than those (ca. 10,000–30,000) reported in our previous work 5. Probably, the higher vacuum (0.1 Torr) and the lower molar ratio (1.1) of diol to diester compared with those in the previous work5 brought these higher M n values.…”

Section: Resultsmentioning

confidence: 51%

“…10,000–30,000) reported in our previous work 5. Probably, the higher vacuum (0.1 Torr) and the lower molar ratio (1.1) of diol to diester compared with those in the previous work5 brought these higher M n values. Concerning the thermal properties, T m values of the polyesters are rather low (43.4–66.8°C) except that (115.6°C) of DMS/BD polyester.…”

Section: Resultsmentioning

confidence: 51%

“…A variety of diols [HO—(CH 2 ) y —OH], y = 2–7] were also used. However, the preliminary experiments and our previous studies4, 5 revealed that 1,4‐butanediol (BD) gave the highest molecular weight and the highest yield. Hence, in this work we used BD as diol, which was dried over Na metal overnight and distilled twice under reduced pressure.…”

Section: Methodsmentioning

confidence: 93%

“…Scheme shows the schematic representation of polycondensation of diesters with diols. The polycondensation was carried out in bulk with stirring in an oil bath using the following optimum conditions 5. DMS (5.22 mL, 40 mmol) and BD (3.90 mL, 44 mmol) (BD/DMS = 1.1 in molar ratio) were placed in a side‐arm Schlenk tube, then Ti(O i Pr) 4 (0.052 mL, 0.2 mol %/monomer) was added into the tube.…”

Section: Methodsmentioning

confidence: 99%

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Synthesis and enzymatic degradation of high molecular weight aliphatic polyesters

Shirahama

Kawaguchi

Aludin

et al. 2001

J. Appl. Polym. Sci.

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The aliphatic polyesters with high molecular weight have been prepared according to two methods. First is the synthesis of the polyesters by polycondensation of dimethyl succinate (DMS) with 1,4‐butanediol (BD) using various metal alkoxides as a catalyst. Among the metal alkoxides used, titanium tetraisopropoxide [Ti(OiPr)4] gave the best results (highest molecular weight and yield). Thus, we have prepared aliphatic polyesters using a variety combinations of diesters [MeOOC—(CH2)x—COOMe, x = 2–8] with BD by the catalysis of Ti(OiPr)4. The polyesters with high number‐average molecular weight (Mn > 35,000), except dimethyl adipate (DMA, x = 4)/BD polyester (Mn = 26,900), were obtained in high yield. The melting temperatures (Tm) of polyesters were relatively low (43.4–66.8°C) except that (115.6°C) of the DMS/BD polyester. Second is the synthesis of high molecular weight polyesters by chain extension reaction of lower molecular weight (Mn = 15,900–26,000) polyesters using hexamethylene diisocyanate (HDI) as a chain extender. The Mn values of chain‐extended polyesters consequently increased more than two times (Mn = 34,700–56,000). The thermal properties of polyesters hardly changed before and after chain extension. Enzymatic degradations of the polyesters were performed using three different enzymes (cholesterol esterase, lipase B, and Rhizopus delemar lipase) before chain extension. The enzymatic degradability varied depending on both thermal properties of polyesters [melting temperature and heat of fusion (crystallinity)] and the substrate specificity of enzymes, but it was the following order: cholesterol esterase > lipase B > R. delemar lipase. The 1H‐NMR spectrum of water‐soluble degraded products of the polyester indicated that the polyester was degraded into a condensation product of diol with diester in a monomer form. The enzymatic degradation of chain extended polyesters was slightly smaller than that before chain extension, but proceeded steadily. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 340–347, 2001

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Section: Resultsmentioning

confidence: 51%

Section: Resultsmentioning

confidence: 51%

Section: Methodsmentioning

confidence: 93%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis and enzymatic degradation of high molecular weight aliphatic polyesters

Shirahama

Kawaguchi

Aludin

et al. 2001

J. Appl. Polym. Sci.

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“…The desire to replace these two catalysts originates from antimony’s negative environmental impact and germanium’s high cost. , Titanium alkoxides are emerging as important polyesterification catalysts due to their high activity, generally accepted view they are environmentally safe and are available at acceptable pricing for performing low-cost industrial processes . A number of studies attest to the relatively high activity of titanium alkoxide catalysts for polyesterification reactions. − Investigation of bulk bis(hydroxyethyl) terephthalate polycondensation reactions to synthesize poly(ethylene terephthalate), PET, showed that the relative catalyst activity was as follows: Ti > Sn > Sb > Zn > Pb > Mn …”

Section: Introductionmentioning

confidence: 99%

Poly(butylene 2,5-furan dicarboxylate), a Biobased Alternative to PBT: Synthesis, Physical Properties, and Crystal Structure

et al. 2013

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This paper describes the synthesis, crystal structure, and physicomechanical properties of a biobased polyester prepared from 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol. Melt-polycondensation experiments were conducted by a two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr] 4 ) as a catalyst. Polymerization conditions (catalyst concentration, reaction time and second stage reaction temperature) were varied to optimize poly(butylene-FDCA), PBF, and molecular weight. A series of PBFs with different M w were characterized by DSC, TGA, DMTA, X-ray diffraction and tensile testing. Influence of molecular weight and melting/ crystallization enthalpy on PBF material tensile properties was explored. Cold-drawing tensile tests at room temperature for PBF with M w 16K to 27K showed a brittle-to-ductile transition. When M w reaches 38K, the Young modulus of PBF remains above 900 MPa, and the elongation at break increases to above 1000%. The mechanical properties, thermal properties and crystal structures of PBF were similar to petroleum derived poly(butylenes-terephthalate), PBT. Fiber diagrams of uniaxially stretched PBF films were collected, indexed, and the unit cell was determined as triclinic (a = 4.78(3) Å, b = 6.03(5) Å, c = 12.3(1) Å, α = 110.1(2)°, β = 121.1(3)°, γ = 100.6(2)°). A crystal structure was derived from this data and final atomic coordinates are reported. We concluded that there is a close similarity of the PBF structure to PBT αand β-forms.

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A study on biodegradable aliphatic poly(tetramethylene succinate): the catalyst dependences of polyester syntheses and their thermal stabilities

Yang

Zhang

Liu

et al. 2003

Polymer Degradation and Stability

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Chain Extension and Enzymatic Degradation of Aliphatic Polyesters.

Cited by 5 publications

References 0 publications

Synthesis and enzymatic degradation of high molecular weight aliphatic polyesters

Synthesis and enzymatic degradation of high molecular weight aliphatic polyesters

Poly(butylene 2,5-furan dicarboxylate), a Biobased Alternative to PBT: Synthesis, Physical Properties, and Crystal Structure

A study on biodegradable aliphatic poly(tetramethylene succinate): the catalyst dependences of polyester syntheses and their thermal stabilities

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