Time-resolved isothermal crystallization of absorbable PGA-co-PLA copolymer by synchrotron small-angle X-ray scattering and wide-angle X-ray diffraction

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

doi:10.1016/s0032-3861(01)00374-3

Cited by 32 publications

(16 citation statements)

References 23 publications

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“…3e) on top of a wellpronounced amorphous halo from 10 to 20 . The XRD pattern of 10%wt ND-ODA/PLLA film also shows clear Bragg peaks of PLLA crystalline phase at 2q ofe17 ande19 (corresponding to (110) crystal reflection [33]), with a significantly suppressed amorphous halo, which is indicative of increased crystallinity of the composite compared to the neat PLLA film. The peaks ate17 were fit with Lorentz functions.…”

Section: Resultsmentioning

confidence: 92%

Fluorescent PLLA-nanodiamond composites for bone tissue engineering

et al. 2011

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Section: Resultsmentioning

confidence: 92%

Fluorescent PLLA-nanodiamond composites for bone tissue engineering

et al. 2011

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“…Semicrystalline polymers were also successfully tested as nucleating agents for PLLA. It was reported that blending with poly(ethylene glycol) (PEG) can accelerate crystallization of PLLA . Similarly, poly(ε‐caprolactone) (PCL) was found to enhance nucleation rate of PLLA …”

Section: Introductionmentioning

confidence: 99%

Isothermal and non‐isothermal crystallization of poly(L‐lactic acid)/poly(butylene terephthalate) blends

Lorenzo

Rubino

Cocca

2014

J of Applied Polymer Sci

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Isothermal and non-isothermal crystallization kinetics of poly(L-lactic acid)/poly(butylene terephthalate) (PLLA/PBT) blends containing PLLA as major component is detailed in this contribution. PLLA and PBT are not miscible, but compatibility of the polymer pair is ensured by interactions between the functional groups of the two polyesters, established upon melt mixing. Crystal polymorphism of the two polyesters is not influenced by blending, as probed by wide-angle X-ray analysis. The addition of PLLA does not affect the temperature range of crystallization kinetics of PBT, nor the crystallinity level attained when the blends are cooled from the melt at constant rate. Conversely, PBT favors crystallization of the biodegradable polyester. The addition of PBT results in an anticipated onset of crystallization of PLLA during cooling at a fixed rate, with a sizeable enhancement of the crystal fraction. Isothermal crystallization analysis confirmed the faster crystallization rate of PLLA in the presence of PBT. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40372.

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“…The mechanical properties as well as biodegradability are very much affected by the crystallinity of the constituent blocks that in turn depends upon the microdomain structure. [6,20] Jeon et al [21] prepared polydisperse multiblock PLLA-b-PCL and triblock PLLA-b-PCL-b-PLLA copolymers. They reported that the multiblock and triblock copolymers were phase separated in the melt since they found a single small angle X-ray scattering (SAXS) reflection that they interpreted as arising from the diffraction of poorly ordered spherical or hexagonally packed cylinders for multiblock copolymers and lamellar microdomains for triblock copolymers (they did not observe higher order peaks in their SAXS measurements).…”

Section: Introductionmentioning

confidence: 99%

Melt Structure and its Transformation by Sequential Crystallization of the Two Blocks within Poly(L‐lactide)‐block‐Poly(ε‐caprolactone) Double Crystalline Diblock Copolymers

Hamley

Parras

Castelletto

et al. 2006

Macro Chemistry & Physics

108

122

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Sequential crystallization of poly(L-lactide) (PLLA) followed by poly(e-caprolactone) (PCL) in double crystalline PLLA-b-PCL diblock copolymers is studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS). Three samples with different compositions are studied. The sample with the shortest PLLA block (32 wt.-% PLLA) crystallizes from a homogeneous melt, the other two (with 44 and 60% PLLA) from microphase separated structures. The microphase structure of the melt is changed as PLLA crystallizes at 122 8C (a temperature at which the PCL block is molten) forming spherulites regardless of composition, even with 32% PLLA. SAXS indicates that a lamellar structure with a different periodicity than that obtained in the melt forms (for melt segregated samples). Where PCL is the majority block, PCL crystallization at 42 8C following PLLA crystallization leads to rearrangement of the lamellar structure, as observed by SAXS, possibly due to local melting at the interphases between domains. POM results showed that PCL crystallizes within previously formed PLLA spherulites. WAXS data indicate that the PLLA unit cell is modified by crystallization of PCL, at least for the two majority PCL samples. The PCL minority sample did not crystallize at 42 8C (well below the PCL homopolymer crystallization temperature), pointing to the influence of pre-crystallization of PLLA on PCL crystallization, although it did crystallize at lower temperature. Crystallization kinetics were examined by DSC and WAXS, with good agreement in general. The crystallization rate of PLLA decreased with increase in PCL content in the copolymers. The crystallization rate of PCL decreased with increasing PLLA content. The Avrami exponents were in general depressed for both components in the block copolymers compared to the parent homopolymers.Polarized optical micrographs during isothermal crystallization of (a) homo-PLLA, (b) homo-PCL, (c) and (d) block copolymer after 30 min at 122 8C and after 15 min at 42 8C.

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Time-resolved isothermal crystallization of absorbable PGA-co-PLA copolymer by synchrotron small-angle X-ray scattering and wide-angle X-ray diffraction

Cited by 32 publications

References 23 publications

Fluorescent PLLA-nanodiamond composites for bone tissue engineering

Fluorescent PLLA-nanodiamond composites for bone tissue engineering

Isothermal and non‐isothermal crystallization of poly(L‐lactic acid)/poly(butylene terephthalate) blends

Melt Structure and its Transformation by Sequential Crystallization of the Two Blocks within Poly(L‐lactide)‐block‐Poly(ε‐caprolactone) Double Crystalline Diblock Copolymers

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