Kinetics of Phase Separation in Poly(ɛ-caprolactone)/Poly(ethylene glycol) Blends

Chuang, Wei‐Tsung; Shih, Kan-Shan; Hong, Po‐Da

doi:10.1007/s10965-004-1868-9

Cited by 36 publications

(16 citation statements)

References 29 publications

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“…The binodal curve is drawn from the data for cloud-point measured, whereas the spinodal curve is determined based on the linear Cahn-Hilliard theory as described in our previous report. 20 As shown in Figure 1, the PCL/PEG blend has an upper-critical-solution-temperature (UCST) type of phase diagram. The nucleation-and-growth (NG) and the spinodal decomposition (SD) take place, respectively, in the metastable region between the binodal and spinodal curves and in the unstable region below the spinodal curve.…”

Section: Resultsmentioning

confidence: 99%

“…And a control of the onset time for crystallization t onset,WAXS by the isothermal crystallization temperature T c provides a way to influence the competition process for a preferred morphology, as we have shown previously in preparing a tunable porous structure using the same system discussed here. 20 For instance, a lower isothermal crystallization temperature, thus an earlier t onset,WAXS , leads to a smaller domains of PEG in the late stage.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, it is possible to tailor the final morphology of a polymer blend for specific applications via a kinetic control of the process of LLPS and crystallization. In a previous paper, 20 we have discussed in detail the phase separation kinetics of a polymer blend poly(ε-caprolactone)/poly(ethylene glycol) (PCL/PEG) by small angle light scattering. In this study, using simultaneous SAXS/DSC and WAXS/DSC we focus on the crystallization kinetics of the PCL/PEG blend, under the influence of an ongoing phase separation.…”

Section: Introductionmentioning

confidence: 99%

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Competition between phase separation and crystallization in a PCL/PEG polymer blend captured by synchronized SAXS, WAXS, and DSC

et al. 2006

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We conducted simultaneous, small-angle, X-ray scattering/differential scanning calorimetry (SAXS/ DSC) and simultaneous, wide-angle, X-ray scattering (WAXS)/DSC measurements for a polymer blend of poly(ε-caprolactone)/poly(ethylene glycol) (PCL/PEG). The time-dependent SAXS/DSC and WAXS/DSC results, measured while the system was quenched below the melting temperature of PCL from a melting state, revealed the competitive behavior between liquid-liquid phase separation and crystallization in the polymer blend. The time-dependent structural evolution extracted from the SAXS/WAXS/DSC results can be characterized by the following four stages in the PCL crystallization process: the induction (I), nucleation (II), growth (III), and late (IV) stages. The influence of the liquid-liquid phase separation on the crystallization of PCL was also observed by phase-contrast microscope and polarized microscope with 1/4λ compensator.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Competition between phase separation and crystallization in a PCL/PEG polymer blend captured by synchronized SAXS, WAXS, and DSC

et al. 2006

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“…Storage temperature did not significantly affect the mechanical integrity, including specimens stored at 55 C which did exhibit a slight degradation in the modulus after 2 months. Group avoid the uncontrolled release that often plagues local delivery systems, differences in the Hildebrand constants and phase separation between the polymer components based on their relative rates of polymer crystallization [39][40][41] justified the use of PEG to induce domains within the cast blended polymer BVF composite to provide porosity via aqueous permeation, PEG dissolution, and extraction from the polymer matrix. 14 This intended polymer matrix skeletonization and porosity impacts the tobramycin release kinetics by transitioning device release mechanisms from aqueous permeation/dissolution-limited to drug diffusion-limited kinetics.…”

Section: Discussionmentioning

confidence: 99%

Molded polymer‐coated composite bone void filler improves tobramycin controlled release kinetics

Brooks

Sinclair²,

Davidoff

et al. 2013

J Biomed Mater Res

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Infection remains a significant problem associated with biomedical implants and orthopedic surgeries, especially in revision total joint replacements. Recent advances in antibiotic-releasing bone void fillers (BVF) provide new opportunities to address these types of device-related orthopedic infections that often lead to substantial economic burdens and reduced quality of life. We report improvements made in fabrication and scalability of an antibiotic-releasing polycaprolactone-calcium carbonate/phosphate ceramic composite BVF using a new solvent-free, molten-cast fabrication process. This strategy provides the ability to tailor drug release kinetics from the BVF composite based on modifications of the inorganic substrate and/or the polymeric component, allowing extended tobramycin release at bactericidal concentrations. The mechanical properties of the new BVF composite are comparable to many reported BVFs and validate the relative homogeneity of fabrication. Most importantly, fabrication quality controls are correlated with favorable drug release kinetics, providing bactericidal activity to 10 weeks in vitro when the polycaprolactone component exceeds 98% w/w of the total polymer fraction. Furthermore, in a time kill study, tobramycin-releasing composite fragments inhibited S. aureus growth over 48 h at inoculums as high as 10(9) CFU/mL. This customizable antibiotic-releasing BVF polymer-inorganic biomaterial should provide osseointegrative and osteoconductive properties while contributing antimicrobial protection to orthopedic sites requiring the use of bone void fillers.

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“…Mixtures of PEG and PCL have also been reported to form a separate microphase system in the whole range of compositions, although PCL has the same solubility parameter value of PEG . In addition, PEG/PCL blends reveal a miscibility window of upper critical solution temperature (UCST) character . Finally, the bibliographic revision shows that PLA/PCL blends are immiscible, in spite of the proximity between the solubility parameters of PLA and PCL (10.1 and 9.2 cal 0.5 /cm 1.5 , respectively) …”

Section: Introductionmentioning

confidence: 99%

Complex phase behavior and state of miscibility in Poly(ethylene glycol)/Poly(l‐lactide‐co‐ε‐caprolactone) Blends

Hernandez‐Montero

Ugartemendia

Amestoy

et al. 2013

J Polym Sci B Polym Phys

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A miscibility and phase behavior study was conducted on poly(ethylene glycol) (PEG)/poly(L-lactide-e-caprolactone) (PLA-co-CL) blends. A single glass transition evolution was determined by differential scanning calorimetry initially suggesting a miscible system; however, the unusual T g bias and subsequent morphological study conducted by polarized light optical microscopy (PLOM) and atomic force microscopy (AFM) evidenced a phase separated system for the whole range of blend compositions. PEG spherulites were found in all blends except for the PEG/PLA-co-CL 20/80 composition, with no interference of the comonomer in the melting point of PEG (T m 5 64 C) and only a small one in crystallinity fraction (X c 5 80% vs. 70%). However, a clear continuous decrease in PEG spherulites growth rate (G) with increasing PLA-co-CL content was determined in the blends isothermally crystallized at 37 C, G being 37 mm/min for the neat PEG and 12 mm/min for the 20 wt % PLA-co-CL blend. The kinetics interference in crystal growth rate of PEG suggests a diluting effect of the PLA-co-CL in the blends; further, PLOM and AFM provided unequivocal evidence of the interfering effect of PLA-co-CL on PEG crystal morphology, demonstrating imperfect crystallization in blends with interfibrillar location of the diluting amorphous component. Significantly, AFM images provided also evidence of amorphous phase separation between PEG and PLA-co-CL. A true T g vs. composition diagram is proposed on the basis of the AFM analysis for phase separated PEG/PLA-co-CL blends revealing the existence of a second PLA-co-CL rich phase. According to the partial miscibility established by AFM analysis, PEG and PLA-co-CL rich phases, depending on blend composition, contain respectively an amount of the minority component leading to a system presenting, for every composition, two T g 's that are different of those of pure components.

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Kinetics of Phase Separation in Poly(ɛ-caprolactone)/Poly(ethylene glycol) Blends

Cited by 36 publications

References 29 publications

Competition between phase separation and crystallization in a PCL/PEG polymer blend captured by synchronized SAXS, WAXS, and DSC

Competition between phase separation and crystallization in a PCL/PEG polymer blend captured by synchronized SAXS, WAXS, and DSC

Molded polymer‐coated composite bone void filler improves tobramycin controlled release kinetics

Complex phase behavior and state of miscibility in Poly(ethylene glycol)/Poly(l‐lactide‐co‐ε‐caprolactone) Blends

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