Time resolved study of shear-induced crystallization of poly(p-dioxanone) polymers under low-shear, nucleation-enhancing shear conditions by small angle light scattering and optical microscopy

Abuzaina, Ferass M.; Fitz, Benjamin D.; Andjelić, Saša; Jamiolkowski, Dennis D.

doi:10.1016/s0032-3861(02)00300-2

Cited by 39 publications

(29 citation statements)

References 20 publications

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“…Moreover, it is generally accepted that appropriate temperature (105-140°C) and b-NA are favorable for the growth of b-form crystal under static condition. However, higher take-off rate and shear rate significantly prevents the formation of b-form crystal [9,18]. It should be noted that, in our case, the lamellar branching of b-form crystal is also suppressed by increasing SR at the theoretically appropriate temperature for b-form crystal formation.…”

Section: Two-dimensional Small-angle X-ray Scattering (2d-saxs)mentioning

confidence: 53%

“…It has been reported that the level of lamellar orientation is closely associated with the restriction of neighboring shish structures, i.e., denser shish structures lead to a higher level of lamellar orientation [27]. In addition, stretching is more powerful in inducing chain extension and orientation, resulting in the formation of oriented a-row nuclei (i.e., shish structures) [18,28]. In light of these, a conclusion can be safely obtained that, in our case, more shish structures in the melt-stretched samples are formed upon increasing SR. Additionally, in the melt-stretched samples, b-NA existing in the space between neighboring shish structures will induce the growth of b-form crystal.…”

Section: Two-dimensional Small-angle X-ray Scattering (2d-saxs)mentioning

confidence: 99%

“…It has been well established that, compared with shear field involved in injection molding, elongational field involved in extrusion-stretched process is much more effective in inducing chain extension and orientation [18], which can be easily controlled by tuning SR at the die exit. Nevertheless, to the best of our knowledge, no literature is available concerning the influence of SR on lamellar branching of b-form crystal.…”

Section: Introductionmentioning

confidence: 99%

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New insight into lamellar branching of β-nucleated isotactic polypropylene upon melt-stretching: WAXD and SAXS study

Liu

Liu²,

Zheng

et al. 2014

J Mater Sci

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Polymer processing generally plays a crucial role in determining the development of microstructure in the fabricated product. In this paper, isotactic polypropylene (iPP) containing 0.1 wt% b-nucleating agent was extruded via a slit die and immediately melt-stretched upon various stretching rates (SR) at the die exit. The microstructure of b-nucleated iPP samples was investigated using two-dimensional wide-angle X-ray diffraction and small-angle X-ray scatterings (2D-WAXD/SAXS) measurements. It is observed that, no matter what SR is, lamellar branching of b-form crystal is formed in meltstretched samples, which is scarcely reported in open literatures. A method is proposed to calculate the crystallinity of daughter lamellae in b-crystal (X b-D ). It is found that X b-D decreases with increasing SR, indicating that lamellar branching of b-form crystal is restrained by higher SR. Such case should be attributed to the denser-oriented structures (e.g., shish) induced by higher SR, leaving a confined space between adjacent-oriented structures for the growth of daughter lamellae.

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Section: Two-dimensional Small-angle X-ray Scattering (2d-saxs)mentioning

confidence: 53%

Section: Two-dimensional Small-angle X-ray Scattering (2d-saxs)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

New insight into lamellar branching of β-nucleated isotactic polypropylene upon melt-stretching: WAXD and SAXS study

Liu

Liu²,

Zheng

et al. 2014

J Mater Sci

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“…As PDO is emerging as an attractive biodegradable polymer; however, there is still a lack of understanding in its structure–property relationships. For example, although both isothermal and nonisothermal crystallization kinetics of PDO have been studied , there is no report on its effect on mechanical and degradation properties as of yet. Furthermore, to our best knowledge, there are few reports on molecular weight measurements, mainly because of limited instrumentation capable of accommodating hexafluoroisopropanol (HFIP), which is the best solvent for high‐molecular‐weight PDO .…”

Section: Introductionmentioning

confidence: 99%

Influence of thermal annealing on mechanical properties and in vitro degradation of poly(p‐dioxanone)

Zhang¹,

Jones²,

Wang³

et al. 2019

Polymer Engineering & Sci

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Poly(p‐dioxanone) (PDO), a versatile poly(ester‐ether), has been used for a variety of biomedical applications. Functional performance of this semicrystalline polymer heavily relies on its crystallinity and crystalline behavior. Upon extended exposure to heat above the glass transition temperature and below the melting temperature, PDO undergoes thermal annealing. Isothermal studies at elevated temperatures utilizing a differential scanning calorimeter were performed in order to determine the most appropriate conditions to anneal the polymer. Of the investigated mechanical properties, yield strength and elastic modulus were significantly improved with annealing. This improvement over nonannealed samples was also observed with samples subjected to phosphate‐buffered saline (PBS) solution at 37°C for 2 weeks. After 1 month continuous immersion in PBS solution, the PDO became brittle with deteriorated elongation at break but maintained yield strength and modulus. At 2 months, all specimens exhibited cracks on the surface and a complete loss of mechanical strength. The enhanced yield strength by thermal annealing creates more opportunities for PDO in medical device implants particularly in applications involving soft tissue repair and hemostasis. POLYM. ENG. SCI., 59:1701–1709 2019. © 2019 Society of Plastics Engineers

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“…Comparison to a-form, b-form iPP has some specific features, such as high ductility. Many researchers are interested in the topics related to b-form iPP [1] , and many research groups [2][3][4][5][6][7][8][9][10][11][12][13][14][15] have investigated and elevated the performance of b-form iPP. Using special techniques can obtain the higher levels of b-form, such as the temperature gradient method [3][4][5] , adding specific nucleators [6,8,11] or flow-induced crystallization [13] , of which the effective and accessible method on the iPP with higher level of b-form is the addition of b-nucleators.…”

Section: Introductionmentioning

confidence: 99%

Influence of β-Nucleators on iPP Crystallization and Morphology

Xiong

Guan

Xiao

et al. 2007

Polymer-Plastics Technology and Engineering

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In this article, the effects of the b-nucleators WBG and WOT on the crystallization behavior and morphology of isotactic polypropylene (iPP) were investigated using a combination of differential scanning calorimetry (DSC), wide-angle X-ray (WAXD), polarized optical microscopy (POM) and atomic force microscopy (AFM). The results showed that the amount of b-form and the spherulite size decreased with increasing WBG contents. At about 0.15 wt. % WBG nucleator, the formation of the b-form was evidently observed. Whereas, for the iPP with low content of WOT nucleator, the formation of the b-form was almost the same as that of pure iPP.

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Time resolved study of shear-induced crystallization of poly(p-dioxanone) polymers under low-shear, nucleation-enhancing shear conditions by small angle light scattering and optical microscopy

Cited by 39 publications

References 20 publications

New insight into lamellar branching of β-nucleated isotactic polypropylene upon melt-stretching: WAXD and SAXS study

New insight into lamellar branching of β-nucleated isotactic polypropylene upon melt-stretching: WAXD and SAXS study

Influence of thermal annealing on mechanical properties and in vitro degradation of poly(p‐dioxanone)

Influence of β-Nucleators on iPP Crystallization and Morphology

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