Synthesis of low-molecular-weight copoly(l-lactic acid/ɛ-caprolactone) by direct copolycondensation in the absence of catalysts, and enzymatic degradation of the polymers

Fukuzaki, Hironobu; Yoshida, Minoru; Asano, Masaharu; Kumakura, Minoru; Mashimo, Tooro; Yuasa, Hisako; Imai, Kyoichi; Yamanaka, Hidetoshi

doi:10.1016/0032-3861(90)90031-s

Cited by 115 publications

(76 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resonances at δ = 1.8 ppm, δ = 5.8 ppm and δ = 6.8 ppm observed in the 1 H-NMR spectrum, can be attributed to the presence of a crotonyl end-group [32]; this group is formed at the initiation step of the polymerization where the α-proton abstraction of the (R,S)-BL could occur resulting in the salt of the unsaturated carboxylic acid as propagating species of reaction, as shown in Figure 3 [27,33]. To determine the comonomer sequencing (random or in block), the most convenient spectrum range is the corresponding to carbonyl carbon [10,13,41]. The expanded 13 C-NMR spectrum of the carbonyl (CO) region of the copolymer shown in Figure 2 indicates the formation of a diblock, because the two CO signals of the blocks BL-BL and CL-CL are strong, whereas the signals of the BL-CL and CL-BL sequences are absent [6].…”

Section: Structural Analysis Of Copolymersmentioning

confidence: 99%

“…Blocks with different physical properties, for example, a soft, amorphous segment together with a hard semicrystalline one, can be used to modulate the thermal and mechanical material behaviour [4,[7][8][9]. The mechanical properties can be controlled by the hard/soft segment ratio [7] and copolymers with various morphologies such as solid, pasty and waxy states, can be obtained according to the monomer composition [6,10]. The soft phase provides elasticity and the degradation behaviour, whereas the rigid phase gives mechanical strength and also acts as a physical crosslinker [6].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ring-opening copolymerization of (R,S)-β-butyrolactone and ε-caprolactone using sodium hydride as initiator

Monsalve¹,

Contreras²,

Laredo³

et al. 2010

Express Polym. Lett.

View full text Add to dashboard Cite

Abstract. Copolymers of racemic β-butyrolactone ((R,S)-BL) and ε-caprolactone (CL), were synthesized by ring-opening polymerization initiated by sodium hydride (NaH). The initiator exhibited a satisfactory catalytic activity, producing copolymers whose yields are greatly influenced by the feed monomer ratio, CL/BL. All polymers obtained were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide angle X-rays scattering, WAXS. The molar composition of copolyesters determined by 1 H-NMR spectra, showed that the incorporation of CL is favoured over the incorporation of (R,S)-BL. Gel permeation chromatography and 13 C-NMR spectra indicated that CL/BL copolymers had block sequence distribution. The TGA analysis of copolymers showed that these copolymers are stable up to temperatures near 200°C, followed by a decomposition process in two steps; the first one is attributed to the (R,S)-BL block degradation and the second to the remaining PCL block. The crystallization process of these copolymers was studied by DSC and WAXS showing that the amorphous (R,S)-BL segments chains did not affect the crystallinity of the PCL blocks.

show abstract

Section: Structural Analysis Of Copolymersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ring-opening copolymerization of (R,S)-β-butyrolactone and ε-caprolactone using sodium hydride as initiator

Monsalve¹,

Contreras²,

Laredo³

et al. 2010

Express Polym. Lett.

View full text Add to dashboard Cite

show abstract

“…[6][7][8][9] Three kinds of lipase were found to significantly accelerate the degradation of PCL: Rhizopus delemer lipase [6], Rhizopus arrhizus lipase, and Pseudomonas lipase [7,8]. Highly crystalline PCL was reported to totally degrade in 4 days in the presence of Pseudomonas lipase [7,8], in contrast with hydrolytic degradation, which lasts several years.…”

Section: Introductionmentioning

confidence: 99%

Hydrolytic and enzymatic degradation of a poly(ε-caprolactone) network

Castilla-Cortázar¹,

Más-Estellés²,

Dueñas³

et al. 2012

Polymer Degradation and Stability

149

116

View full text Add to dashboard Cite

Long-term hydrolytic and enzymatic degradation profiles of poly(ε-caprolactone) (PCL) networks were obtained. The hydrolytic degradation studies were performed in water and phosphate buffer solution (PBS) for 65 weeks. In this case, the degradation rate of PCL networks was faster than previous results in the literature on linear PCL, reaching a weight loss of around 20% in 60 weeks after immersing the samples either in water or PBS conditions. The enzymatic degradation rate in Pseudomonas Lipase for 14 weeks was also studied, with the conclusion being that the degradation profile of PCL networks is lower than for linear PCL, also reaching a 20% weight loss. The weight lost, degree of swelling, and calorimetric and mechanical properties as a function of degradation time were obtained. Furthermore, the morphological changes in the samples were studied carefully through electron microscopy and crystal size through X-ray diffraction. The changes in some properties over the degradation period such as crystallinity, crystal size and Young's modulus were smaller in the case of enzymatic studies, highlighting differences in the degradation mechanism in the two studies, hydrolytic and enzymatic.

show abstract

“…Therefore, 2 Indian Journal of Materials Science modification of PLA is needed in order to compete with other flexible polymers such as polypropylene or polyethylene [4]. There are many techniques to modify PLA such as copolymerization [5,6], blending with other polymers [7,8], the addition of plasticizers [9], the addition of nucleating agents [10], and forming composites with fiber or nanoparticles [11,12].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

Eng

Ibrahim

Zainuddin

et al. 2013

Indian Journal of Materials Science

View full text Add to dashboard Cite

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

show abstract

Synthesis of low-molecular-weight copoly(l-lactic acid/ɛ-caprolactone) by direct copolycondensation in the absence of catalysts, and enzymatic degradation of the polymers

Cited by 115 publications

References 27 publications

Ring-opening copolymerization of (R,S)-β-butyrolactone and ε-caprolactone using sodium hydride as initiator

Ring-opening copolymerization of (R,S)-β-butyrolactone and ε-caprolactone using sodium hydride as initiator

Hydrolytic and enzymatic degradation of a poly(ε-caprolactone) network

Enhancement of Mechanical and Thermal Properties of Polylactic Acid/Polycaprolactone Blends by Hydrophilic Nanoclay

Contact Info

Product

Resources

About