Time-resolved crystallization study of absorbable polymers by synchrotron small-angle X-ray scattering

Andjelić, Saša; Jamiolkowski, Dennis D.; McDivitt, James; Fischer, Jerome; Zhou, Jiangying; Wang, Zhigang; Hsiao, Benjamin S.

doi:10.1002/1099-0488(20010101)39:1<153::aid-polb140>3.0.co;2-9

Cited by 25 publications

(14 citation statements)

References 19 publications

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“…Although many researchers have investigated the degradation behavior, spherulitic crystallization mechanism, and mechanical and thermal properties of this attractive PPDX for the medical device and pharmaceutical fields, [10][11][12][13][14][15][16][17][18][19][20] almost no detailed analysis of the crystal structure and conformation of PPDX has been reported. In this paper, we report the first preparation of lamellar crystals of PPDX grown from a dilute solution by isothermal crystallization.…”

Section: Introductionmentioning

confidence: 99%

X‐Ray and Electron Diffraction Study of Poly(p‐dioxanone)

Furuhashi

Nakayama

Monno

et al. 2004

Macromol. Rapid Commun.

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Summary: Solution‐grown lamellar crystals of poly(p‐dioxanone) (PPDX) have been crystallized isothermally from butane‐1,4‐diol at 100 °C. The crystal structure of PPDX has been determined by interpretation of X‐ray fiber diagrams of PPDX fibers and electron diffraction diagrams of lozenge‐shaped chain‐folder lamellar crystals. The unit cell of PPDX is orthorhombic with space group P212121 and parameters: a = 0.970 nm, b = 0.742 nm, and c (chain axis) = 0.682 nm. There are two chains per unit cell, which exist in an antiparallel arrangement.Transmission electron micrograph of PPDX chain‐folded lamellar crystals obtained by isothermal crystallization and its electron diffraction diagram.imageTransmission electron micrograph of PPDX chain‐folded lamellar crystals obtained by isothermal crystallization and its electron diffraction diagram.

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Section: Introductionmentioning

confidence: 99%

X‐Ray and Electron Diffraction Study of Poly(p‐dioxanone)

Furuhashi

Nakayama

Monno

et al. 2004

Macromol. Rapid Commun.

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“…The details of the SAXS setup are described elsewhere 14. For materials with diffuse phase boundaries, Porod's law predicts the scattered intensity at large angles as follows15, 16 where I raw is the raw intensity, I fl is the intensity arising from thermal‐density fluctuations, K p is the Porod constant, and σ is the interfacial thickness between the crystalline and amorphous regions. A numerical simulation was carried out to obtain the optimal parameters ( I fl , K p , and σ).…”

Section: Methodsmentioning

confidence: 99%

Lamellar morphology and equilibrium melting temperature of syndiotactic polystyrene in β‐crystalline form

Wang

Cheng

Hsu

et al. 2002

J Polym Sci B Polym Phys

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Lamellar morphology and thickness of syndiotactic polystyrene (sPS) samples melt-crystallized at various temperatures were probed using transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS). In addition, the melting temperature and enthalpy of the crystallized samples were characterized with differential scanning calorimetry. Under appropriate thermal treatments, all the samples investigated in this study were crystallized into ␤Ј crystal modification, as revealed by wide-angle X-ray diffraction. From the SAXS intensity profiles, a scattering peak (or shoulder) associated with lamellar features as well as the presence of anomalous scattering at the zero-scattering vector were evidently observed. The peculiar zeroangle scattering was successfully described by the Debye-Bueche model, and subtraction of its contribution from the raw intensity profiles was carried out to deduce the intensity profile merely associated with the lamellar feature. The lamellar thickness obtained from Lorentz-corrected intensity profiles in this manner agrees with that measured from the TEM images, provided that the two-phase model is applied. On the basis of the Gibbs-Thomson equation, the modest estimations of equilibrium melting temperature and the surface free energy of the fold lamellar surface are 292.7 Ϯ 2.7°C and 20.2 Ϯ 2.6 erg/cm 2 , respectively, when lamellar thicknesses measured by TEM are applied.

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“…The slightly lower value was found earlier for the PDS homopolymer (2.5). 20,21 As we mentioned before, the determination of n could not be performed on the rest of the copolymer samples using DSC. This was the result of the crystallization rate being so low that the rate of heat gain in the calorimeter was less than the heat-loss rate, resulting in no net change in the enthalpy signal.…”

Section: G )mentioning

confidence: 99%

A Novel Synthetic Method To Obtain Highly Crystallizable Absorbable Copolyesters

et al. 2003

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A series of undyed 90/10 (mol %) poly(p-dioxanone-co-glycolide) block copolymers were synthesized by ring-opening polymerization, with stannous octoate as a catalyst, utilizing various ratios of monofunctional initiator, dodecanol (DD), to difunctional initiator, diethylene glycol (DEG). The effect of using combinations of DD and DEG on supramolecular crystalline morphology and crystallization kinetics of prepared polylactone copolymers is examined using calorimetric, optical, and X-ray measurements. We found, unexpectedly, that the absorbable copolymer made with the specific initiator ratio of 50/50 (mol %) exhibits outstanding crystallization properties, crystallizing at radically faster rate and to a higher extent than its counterparts made with either DD or DEG alone. The nucleation density of this material is extremely high compared to those of the other copolymers in the series and is even higher than that of the homopolymer, poly(p-dioxanone) (PDS). This unusual behavior is partially explained by the large presence of the longest blocky sequences of glycolate moieties which can serve as effective nucleation sites and strongly facilitate subsequent crystallization of the major PDS phase.

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Time-resolved crystallization study of absorbable polymers by synchrotron small-angle X-ray scattering

Cited by 25 publications

References 19 publications

X‐Ray and Electron Diffraction Study of Poly(p‐dioxanone)

X‐Ray and Electron Diffraction Study of Poly(p‐dioxanone)

Lamellar morphology and equilibrium melting temperature of syndiotactic polystyrene in β‐crystalline form

A Novel Synthetic Method To Obtain Highly Crystallizable Absorbable Copolyesters

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