Synthesis of biodegradable copoly(l-lactic acid/aromatic hydroxy acids) with relatively low molecular weight

Fukuzaki, Hironobu; Yoshida, Minoru; Asano, Masaharu; Kumakura, Minoru; Imasaka, Kazumichi; Nagai, Tsuneji; Mäshimo, T.; Yuasa, Hisako; Imai, Kyoichi; Yamanaka, Hidetoshi

doi:10.1016/0014-3057(90)90139-u

Cited by 30 publications

(25 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a similar manner, copolymerization with 10 mol-% of PheLA gave a poly(LA-co-PheLA) with a M w of 21 000 Da. The molecular weights obtained here were higher than those reported before, [16,21] probably because our solution polycondensation with diphenyl ether as the solvent may be efficient at removing the condensed water from the reaction system. However, a polymer with a molecular weight higher than 100 000 Da could not be obtained in each copolymerization.…”

Section: Synthesis and Characterization Of The Copolymerscontrasting

confidence: 51%

“…[14] This modification is also based on a simple change of the starting monomers, which should preferably be obtained from renewable resources. Even for PLLA, various modifications have been proposed by introducing new chemical functionalities by use of other naturally occurring functional monomers such as L-mandelic acid (L-MA), [15][16][17] L-phenyllactic acid (PheLA), [18] and L-malic acid [19] where the methyl group of L-lactic acid (LA) is substituted by other groups.…”

Section: Introductionmentioning

confidence: 99%

“…Previously, Tabushi et al synthesized an oligomeric copolymer of PheLA and LA by direct copolymerization at 170 8C under reduced pressure. [21] Fukuzaki et al, [15,16] and W. J. Kim et al [17] also synthesized the copolymers of L-MA/LA and PheLA/LA by the same method. Very recently, Korean researchers reported some properties Full Paper: Three types of copolymers of poly(L-lactic acid) (PLLA) were synthesized by direct polycondensation of L-lactic acid and phenyl-substituted a-hydroxy acids (L-phenyllactic acid and D-and L-mandelic acids).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers

Moon

Urayama

Kimura

2003

Macromolecular Bioscience

View full text Add to dashboard Cite

Three types of copolymers of poly(L‐lactic acid) (PLLA) were synthesized by direct polycondensation of L‐lactic acid and phenyl‐substituted α‐hydroxy acids (L‐phenyllactic acid and D‐ and L‐mandelic acids). It was found that the glass transition temperature of the copolymers comprising L‐mandelic acid became significantly higher (from 58 to 69 °C) with increasing content of L‐mandelic acid (from 0 to 50 mol‐%) although the Mw decreased (from 87 000 to 4 000 Da). The cast films of the L‐mandelic acid containing copolymers showed improved tensile properties compared with those of the PLLA film. This may be due to a pinning effect of the L‐mandelic acid units on the helix formation of PLLA, although 30% of the units were racemized. The enzymatic degradability of the L‐mandelic acid containing copolymers was much higher than that of PLLA, as analyzed with Proteinase K® originating from Tritirachium album.Synthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.magnified imageSynthesis of copolymers of L‐lactic acid and phenyl‐substituted α‐hydroxy acids.

show abstract

Section: Synthesis and Characterization Of The Copolymerscontrasting

confidence: 51%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers

Moon

Urayama

Kimura

2003

Macromolecular Bioscience

View full text Add to dashboard Cite

show abstract

“…This novel copolymerization method eliminated the use of initiators to cause them to remain in the polymer as end groups, which was undesirable for drug delivery applications. Numerous authors [8][9][10][11][12][13] claimed that these synthesized poly(esters) were biocompatible with high purity and no catalytic residues and their in vivo degradation control was easy. The objective of this study was to apply modified direct ring-opening copolycondensation in the absence of a catalyst to synthesize a series of copolymers of -CL and a second lactone monomer to enhance the degradation of the homopolymer of -CL.…”

Section: Introductionmentioning

confidence: 99%

“…Several approaches were used to modify the degradation properties of PCL; these strategies include the addition of catalysts, 5 the synthesis of copolymers, 6 and the preparation of polymer blends. 7 A series of biodegradable copolymers of lactic acid and glycolic acid, hydroxy acids, [8][9][10] and lactone [11][12][13] monomers were synthesized and investigated. These poly(esters) had relatively low molecular weights of several 1000s of daltons and were copolymerized by direct polycondensation in the absence of catalysts.…”

Section: Introductionmentioning

confidence: 99%

Comparison of thermal characteristics and degradation properties of ?-caprolactone copolymers

Lin

1999

J. Biomed. Mater. Res.

View full text Add to dashboard Cite

The objective of this study was to enhance the degradation of the homopolymer of epsilon-caprolactone (epsilon-CL) through its copolymerization with a second lactone monomer: delta-valerolactone (delta-VL), gamma-butyrolactone (gamma-BL), gamma-valerolactone (gamma-VL), and gamma-caprolactone (gamma-CL). The influences of the molar ratio and the structure of the second lactone monomers on the molecular weight, melting temperature, crystallinity, and degradation rate of the copolymers were compared and elucidated. The enhancement of degradation of the epsilon-CL polymers was achieved by the addition of a second lactone monomer during the copolymerization process, which prominently depended on the initial molar ratio and the chemical structure of the monomers. The changes in the molecular weight and the melting temperature and the enthalpy of fusion of the copolymers were directly related to the initial molar ratio of two monomers, which further affected the magnitude of the enhancement of the polymer degradation. The degradation rates of copolymers of epsilon-CL/delta-VL with initial molar ratios of 75/25, 80/20, and 85/15% were 7.72, 3.60, and 2.05%/day, respectively. However, the degradation rate of the homopolymer of epsilon-CL was 1. 85%/day. The degradation rates of copolymers of epsilon-CL and three five-member ring lactone monomers were in the order of gamma-BL > gamma-VL > gamma-CL. The number of carbon atoms in the side chain of the lactone monomers determined the hydrophobicity of the polymers, which was not favorable for water penetration causing degradation.

show abstract

Synthesis and characterization of biodegradable poly(1,4‐butanediol succinate)

Song

Sung

1995

J of Applied Polymer Sci

View full text Add to dashboard Cite

SYNOPSISBiodegradable poly( 1,4-butanediol succinate) was synthesized from 1,4-butanediol and succinic anhydride. The synthesized polymer was identified by 'H-NMR spectrometer and FT-IR spectrophotometer. The weight average molecular weights were between 4,600 and 29,000, and molecular weight distributions were in the range of 1.7 and 1.9. The glass transition temperature of poly( 1,4-butanediol succinate) was revealed at 73'C. The crystallization and cold crystallization of the polymers were investigated as a function of heating rate, cooling rate, reheating rate, and molecular weight. The biodegradation behavior of poly( 1,4-butanediol succinate) in micro-organisms such as fungi, actinomycetes, and bacteria was studied by using modified ASTM method. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples. 0 1995

show abstract

Synthesis of biodegradable copoly(l-lactic acid/aromatic hydroxy acids) with relatively low molecular weight

Cited by 30 publications

References 10 publications

Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers

Structural Characterization and Degradability of Poly(L‐lactic acid)s Incorporating Phenyl‐Substituted α‐Hydroxy Acids as Comonomers

Comparison of thermal characteristics and degradation properties of ?-caprolactone copolymers

Synthesis and characterization of biodegradable poly(1,4‐butanediol succinate)

Contact Info

Product

Resources

About